Convert legacy string formatting to f-strings (#4685)

* the changes

* Update driver.py

.git_archival.txt

@@ -1,4 +1,3 @@
 node: $Format:%H$
 node-date: $Format:%cI$
-describe-name: $Format:%(describe:tags=true,match=*[0-9]*)$
-ref-names: $Format:%D$
+describe-name: $Format:%(describe:tags=true,match=[0-9]*)$

.gitattributes

@@ -1 +1,2 @@
 .git_archival.txt  export-subst
+*.py diff=python

.github/workflows/diff_shades.yml

@@ -34,7 +34,8 @@ jobs:
         env:
           GITHUB_TOKEN: ${{ github.token }}
         run: >
-          python scripts/diff_shades_gha_helper.py config ${{ github.event_name }} ${{ matrix.mode }}
+          python scripts/diff_shades_gha_helper.py config ${{ github.event_name }}
+          ${{ matrix.mode }}
 
   analysis:
     name: analysis / ${{ matrix.mode }}
@@ -44,11 +45,11 @@ jobs:
       HATCH_BUILD_HOOKS_ENABLE: "1"
       # Clang is less picky with the C code it's given than gcc (and may
       # generate faster binaries too).
-      CC: clang-14
+      CC: clang-18
     strategy:
       fail-fast: false
       matrix:
-        include: ${{ fromJson(needs.configure.outputs.matrix )}}
+        include: ${{ fromJson(needs.configure.outputs.matrix) }}
 
     steps:
       - name: Checkout this repository (full clone)
@@ -110,19 +111,19 @@ jobs:
           ${{ matrix.baseline-analysis }} ${{ matrix.target-analysis }}
 
       - name: Upload diff report
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: ${{ matrix.mode }}-diff.html
           path: diff.html
 
       - name: Upload baseline analysis
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: ${{ matrix.baseline-analysis }}
           path: ${{ matrix.baseline-analysis }}
 
       - name: Upload target analysis
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: ${{ matrix.target-analysis }}
           path: ${{ matrix.target-analysis }}
@@ -130,14 +131,13 @@ jobs:
       - name: Generate summary file (PR only)
         if: github.event_name == 'pull_request' && matrix.mode == 'preview-changes'
         run: >
-          python helper.py comment-body
-          ${{ matrix.baseline-analysis }} ${{ matrix.target-analysis }}
-          ${{ matrix.baseline-sha }} ${{ matrix.target-sha }}
-          ${{ github.event.pull_request.number }}
+          python helper.py comment-body ${{ matrix.baseline-analysis }}
+          ${{ matrix.target-analysis }} ${{ matrix.baseline-sha }}
+          ${{ matrix.target-sha }} ${{ github.event.pull_request.number }}
 
       - name: Upload summary file (PR only)
         if: github.event_name == 'pull_request' && matrix.mode == 'preview-changes'
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: .pr-comment.json
           path: .pr-comment.json

.github/workflows/pypi_upload.yml

@@ -50,8 +50,8 @@ jobs:
       # Keep cibuildwheel version in sync with below
       - name: Install cibuildwheel and pypyp
         run: |
-          pipx install cibuildwheel==2.21.2
-          pipx install pypyp==1
+          pipx install cibuildwheel==2.22.0
+          pipx install pypyp==1.3.0
       - name: generate matrix
         if: github.event_name != 'pull_request'
         run: |
@@ -92,14 +92,14 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       # Keep cibuildwheel version in sync with above
-      - uses: pypa/cibuildwheel@v2.21.2
+      - uses: pypa/cibuildwheel@v2.23.3
         with:
           only: ${{ matrix.only }}
 
       - name: Upload wheels as workflow artifacts
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
-          name: ${{ matrix.name }}-mypyc-wheels
+          name: ${{ matrix.only }}-mypyc-wheels
           path: ./wheelhouse/*.whl
 
       - if: github.event_name == 'release'

.github/workflows/upload_binary.yml

@@ -13,13 +13,13 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        os: [windows-2019, ubuntu-20.04, macos-latest]
+        os: [windows-2019, ubuntu-22.04, macos-latest]
         include:
           - os: windows-2019
             pathsep: ";"
             asset_name: black_windows.exe
             executable_mime: "application/vnd.microsoft.portable-executable"
-          - os: ubuntu-20.04
+          - os: ubuntu-22.04
             pathsep: ":"
             asset_name: black_linux
             executable_mime: "application/x-executable"

.pre-commit-config.yaml

@@ -24,12 +24,12 @@ repos:
         additional_dependencies: *version_check_dependencies
 
   - repo: https://github.com/pycqa/isort
-    rev: 5.13.2
+    rev: 6.0.1
     hooks:
       - id: isort
 
   - repo: https://github.com/pycqa/flake8
-    rev: 7.1.0
+    rev: 7.2.0
     hooks:
       - id: flake8
         additional_dependencies:
@@ -39,17 +39,21 @@ repos:
         exclude: ^src/blib2to3/
 
   - repo: https://github.com/pre-commit/mirrors-mypy
-    rev: v1.11.2
+    rev: v1.15.0
     hooks:
       - id: mypy
         exclude: ^(docs/conf.py|scripts/generate_schema.py)$
         args: []
         additional_dependencies: &mypy_deps
           - types-PyYAML
+          - types-atheris
           - tomli >= 0.2.6, < 2.0.0
-          - click >= 8.1.0, != 8.1.4, != 8.1.5
+          - click >= 8.2.0
+          # Click is intentionally out-of-sync with pyproject.toml
+          # v8.2 has breaking changes. We work around them at runtime, but we need the newer stubs.
           - packaging >= 22.0
           - platformdirs >= 2.1.0
+          - pytokens >= 0.1.10
           - pytest
           - hypothesis
           - aiohttp >= 3.7.4
@@ -62,14 +66,15 @@ repos:
         args: ["--python-version=3.10"]
         additional_dependencies: *mypy_deps
 
-  - repo: https://github.com/pre-commit/mirrors-prettier
-    rev: v4.0.0-alpha.8
+  - repo: https://github.com/rbubley/mirrors-prettier
+    rev: v3.5.3
     hooks:
       - id: prettier
+        types_or: [markdown, yaml, json]
         exclude: \.github/workflows/diff_shades\.yml
 
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v4.6.0
+    rev: v5.0.0
     hooks:
       - id: end-of-file-fixer
       - id: trailing-whitespace

.readthedocs.yaml

@@ -16,3 +16,6 @@ python:
       path: .
       extra_requirements:
         - d
+
+sphinx:
+  configuration: docs/conf.py

CHANGES.md

@@ -1,5 +1,128 @@
 # Change Log
 
+## Unreleased
+
+### Highlights
+
+<!-- Include any especially major or disruptive changes here -->
+
+### Stable style
+
+<!-- Changes that affect Black's stable style -->
+
+- Fix crash while formatting a long `del` statement containing tuples (#4628)
+- Fix crash while formatting expressions using the walrus operator in complex `with`
+  statements (#4630)
+- Handle `# fmt: skip` followed by a comment at the end of file (#4635)
+- Fix crash when a tuple appears in the `as` clause of a `with` statement (#4634)
+- Fix crash when tuple is used as a context manager inside a `with` statement (#4646)
+- Fix crash on a `\\r\n` (#4673)
+- Fix crash on `await ...` (where `...` is a literal `Ellipsis`) (#4676)
+- Remove support for pre-python 3.7 `await/async` as soft keywords/variable names
+  (#4676)
+
+### Preview style
+
+<!-- Changes that affect Black's preview style -->
+
+- Fix a bug where one-liner functions/conditionals marked with `# fmt: skip` would still
+  be formatted (#4552)
+
+### Configuration
+
+<!-- Changes to how Black can be configured -->
+
+### Packaging
+
+<!-- Changes to how Black is packaged, such as dependency requirements -->
+
+### Parser
+
+<!-- Changes to the parser or to version autodetection -->
+
+- Rewrite tokenizer to improve performance and compliance (#4536)
+- Fix bug where certain unusual expressions (e.g., lambdas) were not accepted in type
+  parameter bounds and defaults. (#4602)
+
+### Performance
+
+<!-- Changes that improve Black's performance. -->
+
+### Output
+
+<!-- Changes to Black's terminal output and error messages -->
+
+### _Blackd_
+
+<!-- Changes to blackd -->
+
+### Integrations
+
+<!-- For example, Docker, GitHub Actions, pre-commit, editors -->
+
+- Fix the version check in the vim file to reject Python 3.8 (#4567)
+- Enhance GitHub Action `psf/black` to read Black version from an additional section in
+  pyproject.toml: `[project.dependency-groups]` (#4606)
+
+### Documentation
+
+<!-- Major changes to documentation and policies. Small docs changes
+     don't need a changelog entry. -->
+
+## 25.1.0
+
+### Highlights
+
+This release introduces the new 2025 stable style (#4558), stabilizing the following
+changes:
+
+- Normalize casing of Unicode escape characters in strings to lowercase (#2916)
+- Fix inconsistencies in whether certain strings are detected as docstrings (#4095)
+- Consistently add trailing commas to typed function parameters (#4164)
+- Remove redundant parentheses in if guards for case blocks (#4214)
+- Add parentheses to if clauses in case blocks when the line is too long (#4269)
+- Whitespace before `# fmt: skip` comments is no longer normalized (#4146)
+- Fix line length computation for certain expressions that involve the power operator
+  (#4154)
+- Check if there is a newline before the terminating quotes of a docstring (#4185)
+- Fix type annotation spacing between `*` and more complex type variable tuple (#4440)
+
+The following changes were not in any previous release:
+
+- Remove parentheses around sole list items (#4312)
+- Generic function definitions are now formatted more elegantly: parameters are split
+  over multiple lines first instead of type parameter definitions (#4553)
+
+### Stable style
+
+- Fix formatting cells in IPython notebooks with magic methods and starting or trailing
+  empty lines (#4484)
+- Fix crash when formatting `with` statements containing tuple generators/unpacking
+  (#4538)
+
+### Preview style
+
+- Fix/remove string merging changing f-string quotes on f-strings with internal quotes
+  (#4498)
+- Collapse multiple empty lines after an import into one (#4489)
+- Prevent `string_processing` and `wrap_long_dict_values_in_parens` from removing
+  parentheses around long dictionary values (#4377)
+- Move `wrap_long_dict_values_in_parens` from the unstable to preview style (#4561)
+
+### Packaging
+
+- Store license identifier inside the `License-Expression` metadata field, see
+  [PEP 639](https://peps.python.org/pep-0639/). (#4479)
+
+### Performance
+
+- Speed up the `is_fstring_start` function in Black's tokenizer (#4541)
+
+### Integrations
+
+- If using stdin with `--stdin-filename` set to a force excluded path, stdin won't be
+  formatted. (#4539)
+
 ## 24.10.0
 
 ### Highlights

CONTRIBUTING.md

@@ -1,10 +1,13 @@
 # Contributing to _Black_
 
-Welcome! Happy to see you willing to make the project better. Have you read the entire
-[user documentation](https://black.readthedocs.io/en/latest/) yet?
+Welcome future contributor! We're happy to see you willing to make the project better.
 
-Our [contributing documentation](https://black.readthedocs.org/en/latest/contributing/)
-contains details on all you need to know about contributing to _Black_, the basics to
-the internals of _Black_.
+If you aren't familiar with _Black_, or are looking for documentation on something
+specific, the [user documentation](https://black.readthedocs.io/en/latest/) is the best
+place to look.
 
-We look forward to your contributions!
+For getting started on contributing, please read the
+[contributing documentation](https://black.readthedocs.org/en/latest/contributing/) for
+all you need to know.
+
+Thank you, and we look forward to your contributions!

README.md

@@ -38,7 +38,7 @@ Try it out now using the [Black Playground](https://black.vercel.app). Watch the
 
 ### Installation
 
-_Black_ can be installed by running `pip install black`. It requires Python 3.8+ to run.
+_Black_ can be installed by running `pip install black`. It requires Python 3.9+ to run.
 If you want to format Jupyter Notebooks, install with `pip install "black[jupyter]"`.
 
 If you can't wait for the latest _hotness_ and want to install from GitHub, use:
@@ -137,8 +137,8 @@ SQLAlchemy, Poetry, PyPA applications (Warehouse, Bandersnatch, Pipenv, virtuale
 pandas, Pillow, Twisted, LocalStack, every Datadog Agent Integration, Home Assistant,
 Zulip, Kedro, OpenOA, FLORIS, ORBIT, WOMBAT, and many more.
 
-The following organizations use _Black_: Facebook, Dropbox, KeepTruckin, Lyft, Mozilla,
-Quora, Duolingo, QuantumBlack, Tesla, Archer Aviation.
+The following organizations use _Black_: Dropbox, KeepTruckin, Lyft, Mozilla, Quora,
+Duolingo, QuantumBlack, Tesla, Archer Aviation.
 
 Are we missing anyone? Let us know.
 

action/main.py

@@ -71,6 +71,7 @@ def read_version_specifier_from_pyproject() -> str:
         return f"=={version}"
 
     arrays = [
+        *pyproject.get("dependency-groups", {}).values(),
         pyproject.get("project", {}).get("dependencies"),
         *pyproject.get("project", {}).get("optional-dependencies", {}).values(),
     ]

autoload/black.vim

@@ -75,8 +75,8 @@ def _initialize_black_env(upgrade=False):
       return True
 
   pyver = sys.version_info[:3]
-  if pyver < (3, 8):
-    print("Sorry, Black requires Python 3.8+ to run.")
+  if pyver < (3, 9):
+    print("Sorry, Black requires Python 3.9+ to run.")
     return False
 
   from pathlib import Path

docs/contributing/release_process.md

@@ -29,8 +29,8 @@ frequently than monthly nets rapidly diminishing returns.
 **You must have `write` permissions for the _Black_ repository to cut a release.**
 
 The 10,000 foot view of the release process is that you prepare a release PR and then
-publish a [GitHub Release]. This triggers [release automation](#release-workflows) that builds
-all release artifacts and publishes them to the various platforms we publish to.
+publish a [GitHub Release]. This triggers [release automation](#release-workflows) that
+builds all release artifacts and publishes them to the various platforms we publish to.
 
 We now have a `scripts/release.py` script to help with cutting the release PRs.
 
@@ -96,8 +96,9 @@ In the end, use your best judgement and ask other maintainers for their thoughts
 
 ## Release workflows
 
-All of _Black_'s release automation uses [GitHub Actions]. All workflows are therefore configured
-using YAML files in the `.github/workflows` directory of the _Black_ repository.
+All of _Black_'s release automation uses [GitHub Actions]. All workflows are therefore
+configured using YAML files in the `.github/workflows` directory of the _Black_
+repository.
 
 They are triggered by the publication of a [GitHub Release].
 

docs/contributing/the_basics.md

@@ -7,7 +7,14 @@ An overview on contributing to the _Black_ project.
 Development on the latest version of Python is preferred. You can use any operating
 system.
 
-Install development dependencies inside a virtual environment of your choice, for
+First clone the _Black_ repository:
+
+```console
+$ git clone https://github.com/psf/black.git
+$ cd black
+```
+
+Then install development dependencies inside a virtual environment of your choice, for
 example:
 
 ```console
@@ -48,13 +55,16 @@ Further examples of invoking the tests
 # Run tests on a specific python version
 (.venv)$ tox -e py39
 
-# pass arguments to pytest
+# Run an individual test
+(.venv)$ pytest -k <test name>
+
+# Pass arguments to pytest
 (.venv)$ tox -e py -- --no-cov
 
-# print full tree diff, see documentation below
+# Print full tree diff, see documentation below
 (.venv)$ tox -e py -- --print-full-tree
 
-# disable diff printing, see documentation below
+# Disable diff printing, see documentation below
 (.venv)$ tox -e py -- --print-tree-diff=False
 ```
 
@@ -99,16 +109,22 @@ default. To turn it off pass `--print-tree-diff=False`.
 `Black` has CI that will check for an entry corresponding to your PR in `CHANGES.md`. If
 you feel this PR does not require a changelog entry please state that in a comment and a
 maintainer can add a `skip news` label to make the CI pass. Otherwise, please ensure you
-have a line in the following format:
+have a line in the following format added below the appropriate header:
 
 ```md
 - `Black` is now more awesome (#X)
 ```
 
+<!---
+The Next PR Number link uses HTML because of a bug in MyST-Parser that double-escapes the ampersand, causing the query parameters to not be processed.
+MyST-Parser issue: https://github.com/executablebooks/MyST-Parser/issues/760
+MyST-Parser stalled fix PR: https://github.com/executablebooks/MyST-Parser/pull/929
+-->
+
 Note that X should be your PR number, not issue number! To workout X, please use
-[Next PR Number](https://ichard26.github.io/next-pr-number/?owner=psf&name=black). This
-is not perfect but saves a lot of release overhead as now the releaser does not need to
-go back and workout what to add to the `CHANGES.md` for each release.
+<a href="https://ichard26.github.io/next-pr-number/?owner=psf&name=black">Next PR
+Number</a>. This is not perfect but saves a lot of release overhead as now the releaser
+does not need to go back and workout what to add to the `CHANGES.md` for each release.
 
 ### Style Changes
 
@@ -116,7 +132,7 @@ If a change would affect the advertised code style, please modify the documentat
 _Black_ code style) to reflect that change. Patches that fix unintended bugs in
 formatting don't need to be mentioned separately though. If the change is implemented
 with the `--preview` flag, please include the change in the future style document
-instead and write the changelog entry under a dedicated "Preview changes" heading.
+instead and write the changelog entry under the dedicated "Preview style" heading.
 
 ### Docs Testing
 
@@ -124,17 +140,17 @@ If you make changes to docs, you can test they still build locally too.
 
 ```console
 (.venv)$ pip install -r docs/requirements.txt
-(.venv)$ pip install -e .[d]
+(.venv)$ pip install -e ".[d]"
 (.venv)$ sphinx-build -a -b html -W docs/ docs/_build/
 ```
 
 ## Hygiene
 
 If you're fixing a bug, add a test. Run it first to confirm it fails, then fix the bug,
-run it again to confirm it's really fixed.
+and run the test again to confirm it's really fixed.
 
-If adding a new feature, add a test. In fact, always add a test. But wait, before adding
-any large feature, first open an issue for us to discuss the idea first.
+If adding a new feature, add a test. In fact, always add a test. If adding a large
+feature, please first open an issue to discuss it beforehand.
 
 ## Finally
 

docs/faq.md

@@ -84,16 +84,19 @@ See [Using _Black_ with other tools](labels/why-pycodestyle-warnings).
 
 ## Which Python versions does Black support?
 
-Currently the runtime requires Python 3.8-3.11. Formatting is supported for files
-containing syntax from Python 3.3 to 3.11. We promise to support at least all Python
-versions that have not reached their end of life. This is the case for both running
-_Black_ and formatting code.
+_Black_ generally supports all Python versions supported by CPython (see
+[the Python devguide](https://devguide.python.org/versions/) for current information).
+We promise to support at least all Python versions that have not reached their end of
+life. This is the case for both running _Black_ and formatting code.
 
 Support for formatting Python 2 code was removed in version 22.0. While we've made no
 plans to stop supporting older Python 3 minor versions immediately, their support might
 also be removed some time in the future without a deprecation period.
 
-Runtime support for 3.7 was removed in version 23.7.0.
+`await`/`async` as soft keywords/indentifiers are no longer supported as of 25.2.0.
+
+Runtime support for 3.6 was removed in version 22.10.0, for 3.7 in version 23.7.0, and
+for 3.8 in version 24.10.0.
 
 ## Why does my linter or typechecker complain after I format my code?
 

docs/getting_started.md

@@ -16,7 +16,7 @@ Also, you can try out _Black_ online for minimal fuss on the
 
 ## Installation
 
-_Black_ can be installed by running `pip install black`. It requires Python 3.8+ to run.
+_Black_ can be installed by running `pip install black`. It requires Python 3.9+ to run.
 If you want to format Jupyter Notebooks, install with `pip install "black[jupyter]"`.
 
 If you use pipx, you can install Black with `pipx install black`.

docs/integrations/editors.md

@@ -236,7 +236,7 @@ Configuration:
 
 #### Installation
 
-This plugin **requires Vim 7.0+ built with Python 3.8+ support**. It needs Python 3.8 to
+This plugin **requires Vim 7.0+ built with Python 3.9+ support**. It needs Python 3.9 to
 be able to run _Black_ inside the Vim process which is much faster than calling an
 external command.
 

docs/integrations/github_actions.md

@@ -37,10 +37,10 @@ the `pyproject.toml` file. `version` can be any
 [valid version specifier](https://packaging.python.org/en/latest/glossary/#term-Version-Specifier)
 or just the version number if you want an exact version. To read the version from the
 `pyproject.toml` file instead, set `use_pyproject` to `true`. This will first look into
-the `tool.black.required-version` field, then the `project.dependencies` array and
-finally the `project.optional-dependencies` table. The action defaults to the latest
-release available on PyPI. Only versions available from PyPI are supported, so no commit
-SHAs or branch names.
+the `tool.black.required-version` field, then the `dependency-groups` table, then the
+`project.dependencies` array and finally the `project.optional-dependencies` table. The
+action defaults to the latest release available on PyPI. Only versions available from
+PyPI are supported, so no commit SHAs or branch names.
 
 If you want to include Jupyter Notebooks, _Black_ must be installed with the `jupyter`
 extra. Installing the extra and including Jupyter Notebook files can be configured via
@@ -74,9 +74,14 @@ If you want to match versions covered by Black's
     version: "~= 22.0"
 ```
 
-If you want to read the version from `pyproject.toml`, set `use_pyproject` to `true`:
+If you want to read the version from `pyproject.toml`, set `use_pyproject` to `true`.
+Note that this requires Python >= 3.11, so using the setup-python action may be
+required, for example:
 
 ```yaml
+- uses: actions/setup-python@v5
+  with:
+    python-version: "3.13"
 - uses: psf/black@stable
   with:
     options: "--check --verbose"

docs/integrations/source_version_control.md

@@ -8,7 +8,7 @@ Use [pre-commit](https://pre-commit.com/). Once you
 repos:
   # Using this mirror lets us use mypyc-compiled black, which is about 2x faster
   - repo: https://github.com/psf/black-pre-commit-mirror
-    rev: 24.10.0
+    rev: 25.1.0
     hooks:
       - id: black
         # It is recommended to specify the latest version of Python
@@ -35,7 +35,7 @@ include Jupyter Notebooks. To use this hook, simply replace the hook's `id: blac
 repos:
   # Using this mirror lets us use mypyc-compiled black, which is about 2x faster
   - repo: https://github.com/psf/black-pre-commit-mirror
-    rev: 24.10.0
+    rev: 25.1.0
     hooks:
       - id: black-jupyter
         # It is recommended to specify the latest version of Python

docs/requirements.txt

@@ -1,9 +1,9 @@
 # Used by ReadTheDocs; pinned requirements for stability.
 
-myst-parser==3.0.1
-Sphinx==7.4.7
+myst-parser==4.0.1
+Sphinx==8.2.3
 # Older versions break Sphinx even though they're declared to be supported.
-docutils==0.20.1
-sphinxcontrib-programoutput==0.17
+docutils==0.21.2
+sphinxcontrib-programoutput==0.18
 sphinx_copybutton==0.5.2
 furo==2024.8.6

docs/the_black_code_style/current_style.md

@@ -250,6 +250,11 @@ exception of [capital "R" prefixes](#rstrings-and-rstrings), unicode literal mar
 (`u`) are removed because they are meaningless in Python 3, and in the case of multiple
 characters "r" is put first as in spoken language: "raw f-string".
 
+Another area where Python allows multiple ways to format a string is escape sequences.
+For example, `"\uabcd"` and `"\uABCD"` evaluate to the same string. _Black_ normalizes
+such escape sequences to lowercase, but uses uppercase for `\N` named character escapes,
+such as `"\N{MEETEI MAYEK LETTER HUK}"`.
+
 The main reason to standardize on a single form of quotes is aesthetics. Having one kind
 of quotes everywhere reduces reader distraction. It will also enable a future version of
 _Black_ to merge consecutive string literals that ended up on the same line (see

docs/the_black_code_style/future_style.md

@@ -2,6 +2,8 @@
 
 ## Preview style
 
+(labels/preview-style)=
+
 Experimental, potentially disruptive style changes are gathered under the `--preview`
 CLI flag. At the end of each year, these changes may be adopted into the default style,
 as described in [The Black Code Style](index.md). Because the functionality is
@@ -20,24 +22,13 @@ demoted from the `--preview` to the `--unstable` style, users can use the
 
 Currently, the following features are included in the preview style:
 
-- `hex_codes_in_unicode_sequences`: normalize casing of Unicode escape characters in
-  strings
-- `unify_docstring_detection`: fix inconsistencies in whether certain strings are
-  detected as docstrings
-- `no_normalize_fmt_skip_whitespace`: whitespace before `# fmt: skip` comments is no
-  longer normalized
-- `typed_params_trailing_comma`: consistently add trailing commas to typed function
-  parameters
-- `is_simple_lookup_for_doublestar_expression`: fix line length computation for certain
-  expressions that involve the power operator
-- `docstring_check_for_newline`: checks if there is a newline before the terminating
-  quotes of a docstring
-- `remove_redundant_guard_parens`: Removes redundant parentheses in `if` guards for
-  `case` blocks.
-- `parens_for_long_if_clauses_in_case_block`: Adds parentheses to `if` clauses in `case`
-  blocks when the line is too long
-- `pep646_typed_star_arg_type_var_tuple`: fix type annotation spacing between * and more
-  complex type variable tuple (i.e. `def fn(*args: *tuple[*Ts, T]) -> None: pass`)
+- `always_one_newline_after_import`: Always force one blank line after import
+  statements, except when the line after the import is a comment or an import statement
+- `wrap_long_dict_values_in_parens`: Add parentheses around long values in dictionaries
+  ([see below](labels/wrap-long-dict-values))
+- `fix_fmt_skip_in_one_liners`: Fix `# fmt: skip` behaviour on one-liner declarations,
+  such as `def foo(): return "mock"  # fmt: skip`, where previously the declaration
+  would have been incorrectly collapsed.
 
 (labels/unstable-features)=
 
@@ -45,13 +36,38 @@ The unstable style additionally includes the following features:
 
 - `string_processing`: split long string literals and related changes
   ([see below](labels/string-processing))
-- `wrap_long_dict_values_in_parens`: add parentheses to long values in dictionaries
-  ([see below](labels/wrap-long-dict-values))
 - `multiline_string_handling`: more compact formatting of expressions involving
   multiline strings ([see below](labels/multiline-string-handling))
 - `hug_parens_with_braces_and_square_brackets`: more compact formatting of nested
   brackets ([see below](labels/hug-parens))
 
+(labels/wrap-long-dict-values)=
+
+### Improved parentheses management in dicts
+
+For dict literals with long values, they are now wrapped in parentheses. Unnecessary
+parentheses are now removed. For example:
+
+```python
+my_dict = {
+    "a key in my dict": a_very_long_variable
+    * and_a_very_long_function_call()
+    / 100000.0,
+    "another key": (short_value),
+}
+```
+
+will be changed to:
+
+```python
+my_dict = {
+    "a key in my dict": (
+        a_very_long_variable * and_a_very_long_function_call() / 100000.0
+    ),
+    "another key": short_value,
+}
+```
+
 (labels/hug-parens)=
 
 ### Improved multiline dictionary and list indentation for sole function parameter
@@ -132,37 +148,11 @@ foo(
 
 _Black_ will split long string literals and merge short ones. Parentheses are used where
 appropriate. When split, parts of f-strings that don't need formatting are converted to
-plain strings. User-made splits are respected when they do not exceed the line length
-limit. Line continuation backslashes are converted into parenthesized strings.
-Unnecessary parentheses are stripped. The stability and status of this feature is
-tracked in [this issue](https://github.com/psf/black/issues/2188).
-
-(labels/wrap-long-dict-values)=
-
-### Improved parentheses management in dicts
-
-For dict literals with long values, they are now wrapped in parentheses. Unnecessary
-parentheses are now removed. For example:
-
-```python
-my_dict = {
-    "a key in my dict": a_very_long_variable
-    * and_a_very_long_function_call()
-    / 100000.0,
-    "another key": (short_value),
-}
-```
-
-will be changed to:
-
-```python
-my_dict = {
-    "a key in my dict": (
-        a_very_long_variable * and_a_very_long_function_call() / 100000.0
-    ),
-    "another key": short_value,
-}
-```
+plain strings. f-strings will not be merged if they contain internal quotes and it would
+change their quotation mark style. User-made splits are respected when they do not
+exceed the line length limit. Line continuation backslashes are converted into
+parenthesized strings. Unnecessary parentheses are stripped. The stability and status of
+this feature istracked in [this issue](https://github.com/psf/black/issues/2188).
 
 (labels/multiline-string-handling)=
 
@@ -277,52 +267,3 @@ s = (  # Top comment
     # Bottom comment
 )
 ```
-
-## Potential future changes
-
-This section lists changes that we may want to make in the future, but that aren't
-implemented yet.
-
-### Using backslashes for with statements
-
-[Backslashes are bad and should be never be used](labels/why-no-backslashes) however
-there is one exception: `with` statements using multiple context managers. Before Python
-3.9 Python's grammar does not allow organizing parentheses around the series of context
-managers.
-
-We don't want formatting like:
-
-```py3
-with make_context_manager1() as cm1, make_context_manager2() as cm2, make_context_manager3() as cm3, make_context_manager4() as cm4:
-    ...  # nothing to split on - line too long
-```
-
-So _Black_ will, when we implement this, format it like this:
-
-```py3
-with \
-     make_context_manager1() as cm1, \
-     make_context_manager2() as cm2, \
-     make_context_manager3() as cm3, \
-     make_context_manager4() as cm4 \
-:
-    ...  # backslashes and an ugly stranded colon
-```
-
-Although when the target version is Python 3.9 or higher, _Black_ uses parentheses
-instead in `--preview` mode (see below) since they're allowed in Python 3.9 and higher.
-
-An alternative to consider if the backslashes in the above formatting are undesirable is
-to use {external:py:obj}`contextlib.ExitStack` to combine context managers in the
-following way:
-
-```python
-with contextlib.ExitStack() as exit_stack:
-    cm1 = exit_stack.enter_context(make_context_manager1())
-    cm2 = exit_stack.enter_context(make_context_manager2())
-    cm3 = exit_stack.enter_context(make_context_manager3())
-    cm4 = exit_stack.enter_context(make_context_manager4())
-    ...
-```
-
-(labels/preview-style)=

docs/usage_and_configuration/the_basics.md

@@ -70,17 +70,17 @@ See also [the style documentation](labels/line-length).
 
 Python versions that should be supported by Black's output. You can run `black --help`
 and look for the `--target-version` option to see the full list of supported versions.
-You should include all versions that your code supports. If you support Python 3.8
-through 3.11, you should write:
+You should include all versions that your code supports. If you support Python 3.11
+through 3.13, you should write:
 
 ```console
-$ black -t py38 -t py39 -t py310 -t py311
+$ black -t py311 -t py312 -t py313
 ```
 
 In a [configuration file](#configuration-via-a-file), you can write:
 
 ```toml
-target-version = ["py38", "py39", "py310", "py311"]
+target-version = ["py311", "py312", "py313"]
 ```
 
 By default, Black will infer target versions from the project metadata in
@@ -269,8 +269,8 @@ configuration file for consistent results across environments.
 
 ```console
 $ black --version
-black, 24.10.0 (compiled: yes)
-$ black --required-version 24.10.0 -c "format = 'this'"
+black, 25.1.0 (compiled: yes)
+$ black --required-version 25.1.0 -c "format = 'this'"
 format = "this"
 $ black --required-version 31.5b2 -c "still = 'beta?!'"
 Oh no! 💥 💔 💥 The required version does not match the running version!
@@ -366,7 +366,7 @@ You can check the version of _Black_ you have installed using the `--version` fl
 
 ```console
 $ black --version
-black, 24.10.0
+black, 25.1.0
 ```
 
 #### `--config`
@@ -478,9 +478,10 @@ operating system, this configuration file should be stored as:
   `XDG_CONFIG_HOME` environment variable is not set)
 
 Note that these are paths to the TOML file itself (meaning that they shouldn't be named
-as `pyproject.toml`), not directories where you store the configuration. Here, `~`
-refers to the path to your home directory. On Windows, this will be something like
-`C:\\Users\UserName`.
+as `pyproject.toml`), not directories where you store the configuration (i.e.,
+`black`/`.black` is the file to create and add your configuration options to, in the
+`~/.config/` directory). Here, `~` refers to the path to your home directory. On
+Windows, this will be something like `C:\\Users\UserName`.
 
 You can also explicitly specify the path to a particular file that you want with
 `--config`. In this situation _Black_ will not look for any other file.

gallery/gallery.py

@@ -7,15 +7,16 @@
 import venv
 import zipfile
 from argparse import ArgumentParser, Namespace
+from collections.abc import Generator
 from concurrent.futures import ThreadPoolExecutor
 from functools import lru_cache, partial
 from pathlib import Path
-from typing import Generator, List, NamedTuple, Optional, Tuple, Union, cast
+from typing import NamedTuple, Optional, Union, cast
 from urllib.request import urlopen, urlretrieve
 
 PYPI_INSTANCE = "https://pypi.org/pypi"
 PYPI_TOP_PACKAGES = (
-    "https://hugovk.github.io/top-pypi-packages/top-pypi-packages-30-days.min.json"
+    "https://hugovk.github.io/top-pypi-packages/top-pypi-packages.min.json"
 )
 INTERNAL_BLACK_REPO = f"{tempfile.gettempdir()}/__black"
 
@@ -54,7 +55,7 @@ def get_pypi_download_url(package: str, version: Optional[str]) -> str:
     return cast(str, source["url"])
 
 
-def get_top_packages() -> List[str]:
+def get_top_packages() -> list[str]:
     with urlopen(PYPI_TOP_PACKAGES) as page:
         result = json.load(page)
 
@@ -150,7 +151,7 @@ def git_switch_branch(
     subprocess.run(args, cwd=repo)
 
 
-def init_repos(options: Namespace) -> Tuple[Path, ...]:
+def init_repos(options: Namespace) -> tuple[Path, ...]:
     options.output.mkdir(exist_ok=True)
 
     if options.top_packages:
@@ -206,7 +207,7 @@ def format_repo_with_version(
     git_switch_branch(black_version.version, repo=black_repo)
     git_switch_branch(current_branch, repo=repo, new=True, from_branch=from_branch)
 
-    format_cmd: List[Union[Path, str]] = [
+    format_cmd: list[Union[Path, str]] = [
         black_runner(black_version.version, black_repo),
         (black_repo / "black.py").resolve(),
         ".",
@@ -222,7 +223,7 @@ def format_repo_with_version(
     return current_branch
 
 
-def format_repos(repos: Tuple[Path, ...], options: Namespace) -> None:
+def format_repos(repos: tuple[Path, ...], options: Namespace) -> None:
     black_versions = tuple(
         BlackVersion(*version.split(":")) for version in options.versions
     )

plugin/black.vim

@@ -21,7 +21,7 @@ endif
 
 if v:version < 700 || !has('python3')
     func! __BLACK_MISSING()
-        echo "The black.vim plugin requires vim7.0+ with Python 3.6 support."
+        echo "The black.vim plugin requires vim7.0+ with Python 3.9 support."
     endfunc
     command! Black :call __BLACK_MISSING()
     command! BlackUpgrade :call __BLACK_MISSING()
@@ -72,12 +72,11 @@ endif
 
 function BlackComplete(ArgLead, CmdLine, CursorPos)
   return [
-\    'target_version=py27',
-\    'target_version=py36',
-\    'target_version=py37',
-\    'target_version=py38',
 \    'target_version=py39',
 \    'target_version=py310',
+\    'target_version=py311',
+\    'target_version=py312',
+\    'target_version=py313',
 \  ]
 endfunction
 

pyproject.toml

@@ -33,7 +33,7 @@ build-backend = "hatchling.build"
 [project]
 name = "black"
 description = "The uncompromising code formatter."
-license = { text = "MIT" }
+license = "MIT"
 requires-python = ">=3.9"
 authors = [
   { name = "Łukasz Langa", email = "lukasz@langa.pl" },
@@ -69,6 +69,7 @@ dependencies = [
   "packaging>=22.0",
   "pathspec>=0.9.0",
   "platformdirs>=2",
+  "pytokens>=0.1.10",
   "tomli>=1.1.0; python_version < '3.11'",
   "typing_extensions>=4.0.1; python_version < '3.11'",
 ]
@@ -125,7 +126,7 @@ macos-max-compat = true
 enable-by-default = false
 dependencies = [
   "hatch-mypyc>=0.16.0",
-  "mypy @ git+https://github.com/python/mypy@bc8119150e49895f7a496ae7ae7362a2828e7e9e",
+  "mypy>=1.12",
   "click>=8.1.7",
 ]
 require-runtime-dependencies = true
@@ -186,16 +187,6 @@ MYPYC_DEBUG_LEVEL = "0"
 # Black needs Clang to compile successfully on Linux.
 CC = "clang"
 
-[tool.cibuildwheel.macos]
-build-frontend = { name = "build", args = ["--no-isolation"] }
-# Unfortunately, hatch doesn't respect MACOSX_DEPLOYMENT_TARGET
-# Note we don't have a good test for this sed horror, so if you futz with it
-# make sure to test manually
-before-build = [
-    "python -m pip install 'hatchling==1.20.0' hatch-vcs hatch-fancy-pypi-readme 'hatch-mypyc>=0.16.0' 'mypy @ git+https://github.com/python/mypy@bc8119150e49895f7a496ae7ae7362a2828e7e9e' 'click>=8.1.7'",
-    """sed -i '' -e "600,700s/'10_16'/os.environ['MACOSX_DEPLOYMENT_TARGET'].replace('.', '_')/" $(python -c 'import hatchling.builders.wheel as h; print(h.__file__)') """,
-]
-
 [tool.isort]
 atomic = true
 profile = "black"
@@ -234,6 +225,8 @@ branch = true
 python_version = "3.9"
 mypy_path = "src"
 strict = true
+strict_bytes = true
+local_partial_types = true
 # Unreachable blocks have been an issue when compiling mypyc, let's try to avoid 'em in the first place.
 warn_unreachable = true
 implicit_reexport = true

scripts/fuzz.py

@@ -5,14 +5,11 @@
 a coverage-guided fuzzer I'm working on.
 """
 
-import re
-
 import hypothesmith
 from hypothesis import HealthCheck, given, settings
 from hypothesis import strategies as st
 
 import black
-from blib2to3.pgen2.tokenize import TokenError
 
 
 # This test uses the Hypothesis and Hypothesmith libraries to generate random
@@ -45,23 +42,7 @@ def test_idempotent_any_syntatically_valid_python(
     compile(src_contents, "<string>", "exec")  # else the bug is in hypothesmith
 
     # Then format the code...
-    try:
-        dst_contents = black.format_str(src_contents, mode=mode)
-    except black.InvalidInput:
-        # This is a bug - if it's valid Python code, as above, Black should be
-        # able to cope with it.  See issues #970, #1012
-        # TODO: remove this try-except block when issues are resolved.
-        return
-    except TokenError as e:
-        if (  # Special-case logic for backslashes followed by newlines or end-of-input
-            e.args[0] == "EOF in multi-line statement"
-            and re.search(r"\\($|\r?\n)", src_contents) is not None
-        ):
-            # This is a bug - if it's valid Python code, as above, Black should be
-            # able to cope with it.  See issue #1012.
-            # TODO: remove this block when the issue is resolved.
-            return
-        raise
+    dst_contents = black.format_str(src_contents, mode=mode)
 
     # And check that we got equivalent and stable output.
     black.assert_equivalent(src_contents, dst_contents)
@@ -80,7 +61,7 @@ def test_idempotent_any_syntatically_valid_python(
     try:
         import sys
 
-        import atheris  # type: ignore[import-not-found]
+        import atheris
     except ImportError:
         pass
     else:

scripts/make_width_table.py

@@ -17,13 +17,13 @@
 """
 
 import sys
+from collections.abc import Iterable
 from os.path import basename, dirname, join
-from typing import Iterable, Tuple
 
 import wcwidth  # type: ignore[import-not-found]
 
 
-def make_width_table() -> Iterable[Tuple[int, int, int]]:
+def make_width_table() -> Iterable[tuple[int, int, int]]:
     start_codepoint = -1
     end_codepoint = -1
     range_width = -2
@@ -53,9 +53,9 @@ def main() -> None:
         f.write(f"""# Generated by {basename(__file__)}
 # wcwidth {wcwidth.__version__}
 # Unicode {wcwidth.list_versions()[-1]}
-from typing import Final, List, Tuple
+from typing import Final
 
-WIDTH_TABLE: Final[List[Tuple[int, int, int]]] = [
+WIDTH_TABLE: Final[list[tuple[int, int, int]]] = [
 """)
         for triple in make_width_table():
             f.write(f"    {triple!r},\n")

scripts/migrate-black.py

@@ -77,7 +77,7 @@ def blackify(base_branch: str, black_command: str, logger: logging.Logger) -> in
         git("commit", "--allow-empty", "-aqC", commit)
 
     for commit in commits:
-        git("branch", "-qD", "%s-black" % commit)
+        git("branch", "-qD", f"{commit}-black")
 
     return 0
 

src/black/__init__.py

@@ -5,24 +5,22 @@
 import sys
 import tokenize
 import traceback
+from collections.abc import (
+    Collection,
+    Generator,
+    Iterator,
+    MutableMapping,
+    Sequence,
+    Sized,
+)
 from contextlib import contextmanager
 from dataclasses import replace
 from datetime import datetime, timezone
 from enum import Enum
 from json.decoder import JSONDecodeError
 from pathlib import Path
-from typing import (
-    Any,
-    Collection,
-    Generator,
-    Iterator,
-    MutableMapping,
-    Optional,
-    Pattern,
-    Sequence,
-    Sized,
-    Union,
-)
+from re import Pattern
+from typing import Any, Optional, Union
 
 import click
 from click.core import ParameterSource
@@ -751,6 +749,12 @@ def get_sources(
     for s in src:
         if s == "-" and stdin_filename:
             path = Path(stdin_filename)
+            if path_is_excluded(stdin_filename, force_exclude):
+                report.path_ignored(
+                    path,
+                    "--stdin-filename matches the --force-exclude regular expression",
+                )
+                continue
             is_stdin = True
         else:
             path = Path(s)

src/black/brackets.py

@@ -1,7 +1,8 @@
 """Builds on top of nodes.py to track brackets."""
 
+from collections.abc import Iterable, Sequence
 from dataclasses import dataclass, field
-from typing import Final, Iterable, Optional, Sequence, Union
+from typing import Final, Optional, Union
 
 from black.nodes import (
     BRACKET,

src/black/cache.py

@@ -5,9 +5,10 @@
 import pickle
 import sys
 import tempfile
+from collections.abc import Iterable
 from dataclasses import dataclass, field
 from pathlib import Path
-from typing import Iterable, NamedTuple
+from typing import NamedTuple
 
 from platformdirs import user_cache_dir
 

src/black/comments.py

@@ -1,7 +1,8 @@
 import re
+from collections.abc import Collection, Iterator
 from dataclasses import dataclass
 from functools import lru_cache
-from typing import Collection, Final, Iterator, Optional, Union
+from typing import Final, Optional, Union
 
 from black.mode import Mode, Preview
 from black.nodes import (
@@ -234,11 +235,7 @@ def convert_one_fmt_off_pair(
                 standalone_comment_prefix += fmt_off_prefix
                 hidden_value = comment.value + "\n" + hidden_value
             if is_fmt_skip:
-                hidden_value += (
-                    comment.leading_whitespace
-                    if Preview.no_normalize_fmt_skip_whitespace in mode
-                    else "  "
-                ) + comment.value
+                hidden_value += comment.leading_whitespace + comment.value
             if hidden_value.endswith("\n"):
                 # That happens when one of the `ignored_nodes` ended with a NEWLINE
                 # leaf (possibly followed by a DEDENT).
@@ -273,7 +270,7 @@ def generate_ignored_nodes(
     Stops at the end of the block.
     """
     if _contains_fmt_skip_comment(comment.value, mode):
-        yield from _generate_ignored_nodes_from_fmt_skip(leaf, comment)
+        yield from _generate_ignored_nodes_from_fmt_skip(leaf, comment, mode)
         return
     container: Optional[LN] = container_of(leaf)
     while container is not None and container.type != token.ENDMARKER:
@@ -312,23 +309,67 @@ def generate_ignored_nodes(
 
 
 def _generate_ignored_nodes_from_fmt_skip(
-    leaf: Leaf, comment: ProtoComment
+    leaf: Leaf, comment: ProtoComment, mode: Mode
 ) -> Iterator[LN]:
     """Generate all leaves that should be ignored by the `# fmt: skip` from `leaf`."""
     prev_sibling = leaf.prev_sibling
     parent = leaf.parent
+    ignored_nodes: list[LN] = []
     # Need to properly format the leaf prefix to compare it to comment.value,
     # which is also formatted
     comments = list_comments(leaf.prefix, is_endmarker=False)
     if not comments or comment.value != comments[0].value:
         return
     if prev_sibling is not None:
-        leaf.prefix = ""
-        siblings = [prev_sibling]
-        while "\n" not in prev_sibling.prefix and prev_sibling.prev_sibling is not None:
-            prev_sibling = prev_sibling.prev_sibling
-            siblings.insert(0, prev_sibling)
-        yield from siblings
+        leaf.prefix = leaf.prefix[comment.consumed :]
+
+        if Preview.fix_fmt_skip_in_one_liners not in mode:
+            siblings = [prev_sibling]
+            while (
+                "\n" not in prev_sibling.prefix
+                and prev_sibling.prev_sibling is not None
+            ):
+                prev_sibling = prev_sibling.prev_sibling
+                siblings.insert(0, prev_sibling)
+            yield from siblings
+            return
+
+        # Generates the nodes to be ignored by `fmt: skip`.
+
+        # Nodes to ignore are the ones on the same line as the
+        # `# fmt: skip` comment, excluding the `# fmt: skip`
+        # node itself.
+
+        # Traversal process (starting at the `# fmt: skip` node):
+        # 1. Move to the `prev_sibling` of the current node.
+        # 2. If `prev_sibling` has children, go to its rightmost leaf.
+        # 3. If there’s no `prev_sibling`, move up to the parent
+        # node and repeat.
+        # 4. Continue until:
+        #    a. You encounter an `INDENT` or `NEWLINE` node (indicates
+        #       start of the line).
+        #    b. You reach the root node.
+
+        # Include all visited LEAVES in the ignored list, except INDENT
+        # or NEWLINE leaves.
+
+        current_node = prev_sibling
+        ignored_nodes = [current_node]
+        if current_node.prev_sibling is None and current_node.parent is not None:
+            current_node = current_node.parent
+        while "\n" not in current_node.prefix and current_node.prev_sibling is not None:
+            leaf_nodes = list(current_node.prev_sibling.leaves())
+            current_node = leaf_nodes[-1] if leaf_nodes else current_node
+
+            if current_node.type in (token.NEWLINE, token.INDENT):
+                current_node.prefix = ""
+                break
+
+            ignored_nodes.insert(0, current_node)
+
+            if current_node.prev_sibling is None and current_node.parent is not None:
+                current_node = current_node.parent
+        yield from ignored_nodes
     elif (
         parent is not None and parent.type == syms.suite and leaf.type == token.NEWLINE
     ):
@@ -336,7 +377,6 @@ def _generate_ignored_nodes_from_fmt_skip(
         # statements. The ignored nodes should be previous siblings of the
         # parent suite node.
         leaf.prefix = ""
-        ignored_nodes: list[LN] = []
         parent_sibling = parent.prev_sibling
         while parent_sibling is not None and parent_sibling.type != syms.suite:
             ignored_nodes.insert(0, parent_sibling)

src/black/concurrency.py

@@ -10,10 +10,11 @@
 import signal
 import sys
 import traceback
+from collections.abc import Iterable
 from concurrent.futures import Executor, ProcessPoolExecutor, ThreadPoolExecutor
 from multiprocessing import Manager
 from pathlib import Path
-from typing import Any, Iterable, Optional
+from typing import Any, Optional
 
 from mypy_extensions import mypyc_attr
 

src/black/debug.py

@@ -1,5 +1,6 @@
+from collections.abc import Iterator
 from dataclasses import dataclass, field
-from typing import Any, Iterator, TypeVar, Union
+from typing import Any, TypeVar, Union
 
 from black.nodes import Visitor
 from black.output import out

src/black/files.py

@@ -1,18 +1,11 @@
 import io
 import os
 import sys
+from collections.abc import Iterable, Iterator, Sequence
 from functools import lru_cache
 from pathlib import Path
-from typing import (
-    TYPE_CHECKING,
-    Any,
-    Iterable,
-    Iterator,
-    Optional,
-    Pattern,
-    Sequence,
-    Union,
-)
+from re import Pattern
+from typing import TYPE_CHECKING, Any, Optional, Union
 
 from mypy_extensions import mypyc_attr
 from packaging.specifiers import InvalidSpecifier, Specifier, SpecifierSet

src/black/handle_ipynb_magics.py

@@ -43,7 +43,6 @@
     "time",
     "timeit",
 ))
-TOKEN_HEX = secrets.token_hex
 
 
 @dataclasses.dataclass(frozen=True)
@@ -160,7 +159,7 @@ def mask_cell(src: str) -> tuple[str, list[Replacement]]:
 
     becomes
 
-        "25716f358c32750e"
+        b"25716f358c32750"
         'foo'
 
     The replacements are returned, along with the transformed code.
@@ -178,18 +177,32 @@ def mask_cell(src: str) -> tuple[str, list[Replacement]]:
     from IPython.core.inputtransformer2 import TransformerManager
 
     transformer_manager = TransformerManager()
+    # A side effect of the following transformation is that it also removes any
+    # empty lines at the beginning of the cell.
     transformed = transformer_manager.transform_cell(src)
     transformed, cell_magic_replacements = replace_cell_magics(transformed)
     replacements += cell_magic_replacements
     transformed = transformer_manager.transform_cell(transformed)
     transformed, magic_replacements = replace_magics(transformed)
-    if len(transformed.splitlines()) != len(src.splitlines()):
+    if len(transformed.strip().splitlines()) != len(src.strip().splitlines()):
         # Multi-line magic, not supported.
         raise NothingChanged
     replacements += magic_replacements
     return transformed, replacements
 
 
+def create_token(n_chars: int) -> str:
+    """Create a randomly generated token that is n_chars characters long."""
+    assert n_chars > 0
+    n_bytes = max(n_chars // 2 - 1, 1)
+    token = secrets.token_hex(n_bytes)
+    if len(token) + 3 > n_chars:
+        token = token[:-1]
+    # We use a bytestring so that the string does not get interpreted
+    # as a docstring.
+    return f'b"{token}"'
+
+
 def get_token(src: str, magic: str) -> str:
     """Return randomly generated token to mask IPython magic with.
 
@@ -199,11 +212,11 @@ def get_token(src: str, magic: str) -> str:
     not already present anywhere else in the cell.
     """
     assert magic
-    nbytes = max(len(magic) // 2 - 1, 1)
-    token = TOKEN_HEX(nbytes)
+    n_chars = len(magic)
+    token = create_token(n_chars)
     counter = 0
     while token in src:
-        token = TOKEN_HEX(nbytes)
+        token = create_token(n_chars)
         counter += 1
         if counter > 100:
             raise AssertionError(
@@ -211,9 +224,7 @@ def get_token(src: str, magic: str) -> str:
                 "Please report a bug on https://github.com/psf/black/issues.  "
                 f"The magic might be helpful: {magic}"
             ) from None
-    if len(token) + 2 < len(magic):
-        token = f"{token}."
-    return f'"{token}"'
+    return token
 
 
 def replace_cell_magics(src: str) -> tuple[str, list[Replacement]]:
@@ -269,7 +280,7 @@ def replace_magics(src: str) -> tuple[str, list[Replacement]]:
     magic_finder = MagicFinder()
     magic_finder.visit(ast.parse(src))
     new_srcs = []
-    for i, line in enumerate(src.splitlines(), start=1):
+    for i, line in enumerate(src.split("\n"), start=1):
         if i in magic_finder.magics:
             offsets_and_magics = magic_finder.magics[i]
             if len(offsets_and_magics) != 1:  # pragma: nocover

src/black/linegen.py

@@ -4,10 +4,11 @@
 
 import re
 import sys
+from collections.abc import Collection, Iterator
 from dataclasses import replace
 from enum import Enum, auto
 from functools import partial, wraps
-from typing import Collection, Iterator, Optional, Union, cast
+from typing import Optional, Union, cast
 
 from black.brackets import (
     COMMA_PRIORITY,
@@ -39,11 +40,13 @@
     ensure_visible,
     fstring_to_string,
     get_annotation_type,
+    has_sibling_with_type,
     is_arith_like,
     is_async_stmt_or_funcdef,
     is_atom_with_invisible_parens,
     is_docstring,
     is_empty_tuple,
+    is_generator,
     is_lpar_token,
     is_multiline_string,
     is_name_token,
@@ -54,6 +57,8 @@
     is_rpar_token,
     is_stub_body,
     is_stub_suite,
+    is_tuple,
+    is_tuple_containing_star,
     is_tuple_containing_walrus,
     is_type_ignore_comment_string,
     is_vararg,
@@ -64,7 +69,7 @@
 )
 from black.numerics import normalize_numeric_literal
 from black.strings import (
-    fix_docstring,
+    fix_multiline_docstring,
     get_string_prefix,
     normalize_string_prefix,
     normalize_string_quotes,
@@ -411,10 +416,9 @@ def foo(a: (int), b: (float) = 7): ...
         yield from self.visit_default(node)
 
     def visit_STRING(self, leaf: Leaf) -> Iterator[Line]:
-        if Preview.hex_codes_in_unicode_sequences in self.mode:
-            normalize_unicode_escape_sequences(leaf)
+        normalize_unicode_escape_sequences(leaf)
 
-        if is_docstring(leaf, self.mode) and not re.search(r"\\\s*\n", leaf.value):
+        if is_docstring(leaf) and not re.search(r"\\\s*\n", leaf.value):
             # We're ignoring docstrings with backslash newline escapes because changing
             # indentation of those changes the AST representation of the code.
             if self.mode.string_normalization:
@@ -441,7 +445,7 @@ def visit_STRING(self, leaf: Leaf) -> Iterator[Line]:
             indent = " " * 4 * self.current_line.depth
 
             if is_multiline_string(leaf):
-                docstring = fix_docstring(docstring, indent)
+                docstring = fix_multiline_docstring(docstring, indent)
             else:
                 docstring = docstring.strip()
 
@@ -485,10 +489,7 @@ def visit_STRING(self, leaf: Leaf) -> Iterator[Line]:
                     and len(indent) + quote_len <= self.mode.line_length
                     and not has_trailing_backslash
                 ):
-                    if (
-                        Preview.docstring_check_for_newline in self.mode
-                        and leaf.value[-1 - quote_len] == "\n"
-                    ):
+                    if leaf.value[-1 - quote_len] == "\n":
                         leaf.value = prefix + quote + docstring + quote
                     else:
                         leaf.value = prefix + quote + docstring + "\n" + indent + quote
@@ -506,6 +507,19 @@ def visit_NUMBER(self, leaf: Leaf) -> Iterator[Line]:
         normalize_numeric_literal(leaf)
         yield from self.visit_default(leaf)
 
+    def visit_atom(self, node: Node) -> Iterator[Line]:
+        """Visit any atom"""
+        if len(node.children) == 3:
+            first = node.children[0]
+            last = node.children[-1]
+            if (first.type == token.LSQB and last.type == token.RSQB) or (
+                first.type == token.LBRACE and last.type == token.RBRACE
+            ):
+                # Lists or sets of one item
+                maybe_make_parens_invisible_in_atom(node.children[1], parent=node)
+
+        yield from self.visit_default(node)
+
     def visit_fstring(self, node: Node) -> Iterator[Line]:
         # currently we don't want to format and split f-strings at all.
         string_leaf = fstring_to_string(node)
@@ -583,8 +597,7 @@ def __post_init__(self) -> None:
         # PEP 634
         self.visit_match_stmt = self.visit_match_case
         self.visit_case_block = self.visit_match_case
-        if Preview.remove_redundant_guard_parens in self.mode:
-            self.visit_guard = partial(v, keywords=Ø, parens={"if"})
+        self.visit_guard = partial(v, keywords=Ø, parens={"if"})
 
 
 def _hugging_power_ops_line_to_string(
@@ -768,26 +781,29 @@ def left_hand_split(
     Prefer RHS otherwise.  This is why this function is not symmetrical with
     :func:`right_hand_split` which also handles optional parentheses.
     """
-    tail_leaves: list[Leaf] = []
-    body_leaves: list[Leaf] = []
-    head_leaves: list[Leaf] = []
-    current_leaves = head_leaves
-    matching_bracket: Optional[Leaf] = None
-    for leaf in line.leaves:
-        if (
-            current_leaves is body_leaves
-            and leaf.type in CLOSING_BRACKETS
-            and leaf.opening_bracket is matching_bracket
-            and isinstance(matching_bracket, Leaf)
-        ):
-            ensure_visible(leaf)
-            ensure_visible(matching_bracket)
-            current_leaves = tail_leaves if body_leaves else head_leaves
-        current_leaves.append(leaf)
-        if current_leaves is head_leaves:
-            if leaf.type in OPENING_BRACKETS:
-                matching_bracket = leaf
-                current_leaves = body_leaves
+    for leaf_type in [token.LPAR, token.LSQB]:
+        tail_leaves: list[Leaf] = []
+        body_leaves: list[Leaf] = []
+        head_leaves: list[Leaf] = []
+        current_leaves = head_leaves
+        matching_bracket: Optional[Leaf] = None
+        for leaf in line.leaves:
+            if (
+                current_leaves is body_leaves
+                and leaf.type in CLOSING_BRACKETS
+                and leaf.opening_bracket is matching_bracket
+                and isinstance(matching_bracket, Leaf)
+            ):
+                ensure_visible(leaf)
+                ensure_visible(matching_bracket)
+                current_leaves = tail_leaves if body_leaves else head_leaves
+            current_leaves.append(leaf)
+            if current_leaves is head_leaves:
+                if leaf.type == leaf_type:
+                    matching_bracket = leaf
+                    current_leaves = body_leaves
+        if matching_bracket and tail_leaves:
+            break
     if not matching_bracket or not tail_leaves:
         raise CannotSplit("No brackets found")
 
@@ -954,29 +970,7 @@ def _maybe_split_omitting_optional_parens(
         try:
             # The RHSResult Omitting Optional Parens.
             rhs_oop = _first_right_hand_split(line, omit=omit)
-            is_split_right_after_equal = (
-                len(rhs.head.leaves) >= 2 and rhs.head.leaves[-2].type == token.EQUAL
-            )
-            rhs_head_contains_brackets = any(
-                leaf.type in BRACKETS for leaf in rhs.head.leaves[:-1]
-            )
-            # the -1 is for the ending optional paren
-            rhs_head_short_enough = is_line_short_enough(
-                rhs.head, mode=replace(mode, line_length=mode.line_length - 1)
-            )
-            rhs_head_explode_blocked_by_magic_trailing_comma = (
-                rhs.head.magic_trailing_comma is None
-            )
-            if (
-                not (
-                    is_split_right_after_equal
-                    and rhs_head_contains_brackets
-                    and rhs_head_short_enough
-                    and rhs_head_explode_blocked_by_magic_trailing_comma
-                )
-                # the omit optional parens split is preferred by some other reason
-                or _prefer_split_rhs_oop_over_rhs(rhs_oop, rhs, mode)
-            ):
+            if _prefer_split_rhs_oop_over_rhs(rhs_oop, rhs, mode):
                 yield from _maybe_split_omitting_optional_parens(
                     rhs_oop, line, mode, features=features, omit=omit
                 )
@@ -987,8 +981,15 @@ def _maybe_split_omitting_optional_parens(
             if line.is_chained_assignment:
                 pass
 
-            elif not can_be_split(rhs.body) and not is_line_short_enough(
-                rhs.body, mode=mode
+            elif (
+                not can_be_split(rhs.body)
+                and not is_line_short_enough(rhs.body, mode=mode)
+                and not (
+                    Preview.wrap_long_dict_values_in_parens
+                    and rhs.opening_bracket.parent
+                    and rhs.opening_bracket.parent.parent
+                    and rhs.opening_bracket.parent.parent.type == syms.dictsetmaker
+                )
             ):
                 raise CannotSplit(
                     "Splitting failed, body is still too long and can't be split."
@@ -1019,6 +1020,44 @@ def _prefer_split_rhs_oop_over_rhs(
     Returns whether we should prefer the result from a split omitting optional parens
     (rhs_oop) over the original (rhs).
     """
+    # contains unsplittable type ignore
+    if (
+        rhs_oop.head.contains_unsplittable_type_ignore()
+        or rhs_oop.body.contains_unsplittable_type_ignore()
+        or rhs_oop.tail.contains_unsplittable_type_ignore()
+    ):
+        return True
+
+    # Retain optional parens around dictionary values
+    if (
+        Preview.wrap_long_dict_values_in_parens
+        and rhs.opening_bracket.parent
+        and rhs.opening_bracket.parent.parent
+        and rhs.opening_bracket.parent.parent.type == syms.dictsetmaker
+        and rhs.body.bracket_tracker.delimiters
+    ):
+        # Unless the split is inside the key
+        return any(leaf.type == token.COLON for leaf in rhs_oop.tail.leaves)
+
+    # the split is right after `=`
+    if not (len(rhs.head.leaves) >= 2 and rhs.head.leaves[-2].type == token.EQUAL):
+        return True
+
+    # the left side of assignment contains brackets
+    if not any(leaf.type in BRACKETS for leaf in rhs.head.leaves[:-1]):
+        return True
+
+    # the left side of assignment is short enough (the -1 is for the ending optional
+    # paren)
+    if not is_line_short_enough(
+        rhs.head, mode=replace(mode, line_length=mode.line_length - 1)
+    ):
+        return True
+
+    # the left side of assignment won't explode further because of magic trailing comma
+    if rhs.head.magic_trailing_comma is not None:
+        return True
+
     # If we have multiple targets, we prefer more `=`s on the head vs pushing them to
     # the body
     rhs_head_equal_count = [leaf.type for leaf in rhs.head.leaves].count(token.EQUAL)
@@ -1046,10 +1085,6 @@ def _prefer_split_rhs_oop_over_rhs(
             # the first line is short enough
             and is_line_short_enough(rhs_oop.head, mode=mode)
         )
-        # contains unsplittable type ignore
-        or rhs_oop.head.contains_unsplittable_type_ignore()
-        or rhs_oop.body.contains_unsplittable_type_ignore()
-        or rhs_oop.tail.contains_unsplittable_type_ignore()
     )
 
 
@@ -1094,12 +1129,7 @@ def _ensure_trailing_comma(
         return False
     # Don't add commas if we already have any commas
     if any(
-        leaf.type == token.COMMA
-        and (
-            Preview.typed_params_trailing_comma not in original.mode
-            or not is_part_of_annotation(leaf)
-        )
-        for leaf in leaves
+        leaf.type == token.COMMA and not is_part_of_annotation(leaf) for leaf in leaves
     ):
         return False
 
@@ -1380,11 +1410,7 @@ def normalize_invisible_parens(  # noqa: C901
             )
 
         # Add parentheses around if guards in case blocks
-        if (
-            isinstance(child, Node)
-            and child.type == syms.guard
-            and Preview.parens_for_long_if_clauses_in_case_block in mode
-        ):
+        if isinstance(child, Node) and child.type == syms.guard:
             normalize_invisible_parens(
                 child, parens_after={"if"}, mode=mode, features=features
             )
@@ -1602,6 +1628,12 @@ def maybe_make_parens_invisible_in_atom(
         node.type not in (syms.atom, syms.expr)
         or is_empty_tuple(node)
         or is_one_tuple(node)
+        or (is_tuple(node) and parent.type == syms.asexpr_test)
+        or (
+            is_tuple(node)
+            and parent.type == syms.with_stmt
+            and has_sibling_with_type(node, token.COMMA)
+        )
         or (is_yield(node) and parent.type != syms.expr_stmt)
         or (
             # This condition tries to prevent removing non-optional brackets
@@ -1611,6 +1643,8 @@ def maybe_make_parens_invisible_in_atom(
             and max_delimiter_priority_in_atom(node) >= COMMA_PRIORITY
         )
         or is_tuple_containing_walrus(node)
+        or is_tuple_containing_star(node)
+        or is_generator(node)
     ):
         return False
 
@@ -1623,6 +1657,7 @@ def maybe_make_parens_invisible_in_atom(
             syms.except_clause,
             syms.funcdef,
             syms.with_stmt,
+            syms.testlist_gexp,
             syms.tname,
             # these ones aren't useful to end users, but they do please fuzzers
             syms.for_stmt,
@@ -1642,9 +1677,6 @@ def maybe_make_parens_invisible_in_atom(
             not is_type_ignore_comment_string(middle.prefix.strip())
         ):
             first.value = ""
-            if first.prefix.strip():
-                # Preserve comments before first paren
-                middle.prefix = first.prefix + middle.prefix
             last.value = ""
         maybe_make_parens_invisible_in_atom(
             middle,
@@ -1656,6 +1688,13 @@ def maybe_make_parens_invisible_in_atom(
             # Strip the invisible parens from `middle` by replacing
             # it with the child in-between the invisible parens
             middle.replace(middle.children[1])
+
+            if middle.children[0].prefix.strip():
+                # Preserve comments before first paren
+                middle.children[1].prefix = (
+                    middle.children[0].prefix + middle.children[1].prefix
+                )
+
             if middle.children[-1].prefix.strip():
                 # Preserve comments before last paren
                 last.prefix = middle.children[-1].prefix + last.prefix

src/black/lines.py

@@ -1,7 +1,8 @@
 import itertools
 import math
+from collections.abc import Callable, Iterator, Sequence
 from dataclasses import dataclass, field
-from typing import Callable, Iterator, Optional, Sequence, TypeVar, Union, cast
+from typing import Optional, TypeVar, Union, cast
 
 from black.brackets import COMMA_PRIORITY, DOT_PRIORITY, BracketTracker
 from black.mode import Mode, Preview
@@ -203,9 +204,7 @@ def _is_triple_quoted_string(self) -> bool:
     @property
     def is_docstring(self) -> bool:
         """Is the line a docstring?"""
-        if Preview.unify_docstring_detection not in self.mode:
-            return self._is_triple_quoted_string
-        return bool(self) and is_docstring(self.leaves[0], self.mode)
+        return bool(self) and is_docstring(self.leaves[0])
 
     @property
     def is_chained_assignment(self) -> bool:
@@ -670,6 +669,15 @@ def _maybe_empty_lines(self, current_line: Line) -> tuple[int, int]:  # noqa: C9
                 current_line, before, user_had_newline
             )
 
+        if (
+            self.previous_line.is_import
+            and self.previous_line.depth == 0
+            and current_line.depth == 0
+            and not current_line.is_import
+            and Preview.always_one_newline_after_import in self.mode
+        ):
+            return 1, 0
+
         if (
             self.previous_line.is_import
             and not current_line.is_import

src/black/mode.py

@@ -196,28 +196,19 @@ def supports_feature(target_versions: set[TargetVersion], feature: Feature) -> b
 class Preview(Enum):
     """Individual preview style features."""
 
-    hex_codes_in_unicode_sequences = auto()
     # NOTE: string_processing requires wrap_long_dict_values_in_parens
     # for https://github.com/psf/black/issues/3117 to be fixed.
     string_processing = auto()
     hug_parens_with_braces_and_square_brackets = auto()
-    unify_docstring_detection = auto()
-    no_normalize_fmt_skip_whitespace = auto()
     wrap_long_dict_values_in_parens = auto()
     multiline_string_handling = auto()
-    typed_params_trailing_comma = auto()
-    is_simple_lookup_for_doublestar_expression = auto()
-    docstring_check_for_newline = auto()
-    remove_redundant_guard_parens = auto()
-    parens_for_long_if_clauses_in_case_block = auto()
-    pep646_typed_star_arg_type_var_tuple = auto()
+    always_one_newline_after_import = auto()
+    fix_fmt_skip_in_one_liners = auto()
 
 
 UNSTABLE_FEATURES: set[Preview] = {
     # Many issues, see summary in https://github.com/psf/black/issues/4042
     Preview.string_processing,
-    # See issues #3452 and #4158
-    Preview.wrap_long_dict_values_in_parens,
     # See issue #4159
     Preview.multiline_string_handling,
     # See issue #4036 (crash), #4098, #4099 (proposed tweaks)

src/black/nodes.py

@@ -3,7 +3,8 @@
 """
 
 import sys
-from typing import Final, Generic, Iterator, Literal, Optional, TypeVar, Union
+from collections.abc import Iterator
+from typing import Final, Generic, Literal, Optional, TypeVar, Union
 
 if sys.version_info >= (3, 10):
     from typing import TypeGuard
@@ -13,7 +14,7 @@
 from mypy_extensions import mypyc_attr
 
 from black.cache import CACHE_DIR
-from black.mode import Mode, Preview
+from black.mode import Mode
 from black.strings import get_string_prefix, has_triple_quotes
 from blib2to3 import pygram
 from blib2to3.pgen2 import token
@@ -243,13 +244,7 @@ def whitespace(leaf: Leaf, *, complex_subscript: bool, mode: Mode) -> str:  # no
         elif (
             prevp.type == token.STAR
             and parent_type(prevp) == syms.star_expr
-            and (
-                parent_type(prevp.parent) == syms.subscriptlist
-                or (
-                    Preview.pep646_typed_star_arg_type_var_tuple in mode
-                    and parent_type(prevp.parent) == syms.tname_star
-                )
-            )
+            and parent_type(prevp.parent) in (syms.subscriptlist, syms.tname_star)
         ):
             # No space between typevar tuples or unpacking them.
             return NO
@@ -550,7 +545,7 @@ def is_arith_like(node: LN) -> bool:
     }
 
 
-def is_docstring(node: NL, mode: Mode) -> bool:
+def is_docstring(node: NL) -> bool:
     if isinstance(node, Leaf):
         if node.type != token.STRING:
             return False
@@ -560,8 +555,7 @@ def is_docstring(node: NL, mode: Mode) -> bool:
             return False
 
     if (
-        Preview.unify_docstring_detection in mode
-        and node.parent
+        node.parent
         and node.parent.type == syms.simple_stmt
         and not node.parent.prev_sibling
         and node.parent.parent
@@ -609,6 +603,17 @@ def is_one_tuple(node: LN) -> bool:
     )
 
 
+def is_tuple(node: LN) -> bool:
+    """Return True if `node` holds a tuple."""
+    if node.type != syms.atom:
+        return False
+    gexp = unwrap_singleton_parenthesis(node)
+    if gexp is None or gexp.type != syms.testlist_gexp:
+        return False
+
+    return True
+
+
 def is_tuple_containing_walrus(node: LN) -> bool:
     """Return True if `node` holds a tuple that contains a walrus operator."""
     if node.type != syms.atom:
@@ -620,6 +625,28 @@ def is_tuple_containing_walrus(node: LN) -> bool:
     return any(child.type == syms.namedexpr_test for child in gexp.children)
 
 
+def is_tuple_containing_star(node: LN) -> bool:
+    """Return True if `node` holds a tuple that contains a star operator."""
+    if node.type != syms.atom:
+        return False
+    gexp = unwrap_singleton_parenthesis(node)
+    if gexp is None or gexp.type != syms.testlist_gexp:
+        return False
+
+    return any(child.type == syms.star_expr for child in gexp.children)
+
+
+def is_generator(node: LN) -> bool:
+    """Return True if `node` holds a generator."""
+    if node.type != syms.atom:
+        return False
+    gexp = unwrap_singleton_parenthesis(node)
+    if gexp is None or gexp.type != syms.testlist_gexp:
+        return False
+
+    return any(child.type == syms.old_comp_for for child in gexp.children)
+
+
 def is_one_sequence_between(
     opening: Leaf,
     closing: Leaf,
@@ -1031,3 +1058,21 @@ def furthest_ancestor_with_last_leaf(leaf: Leaf) -> LN:
     while node.parent and node.parent.children and node is node.parent.children[-1]:
         node = node.parent
     return node
+
+
+def has_sibling_with_type(node: LN, type: int) -> bool:
+    # Check previous siblings
+    sibling = node.prev_sibling
+    while sibling is not None:
+        if sibling.type == type:
+            return True
+        sibling = sibling.prev_sibling
+
+    # Check next siblings
+    sibling = node.next_sibling
+    while sibling is not None:
+        if sibling.type == type:
+            return True
+        sibling = sibling.next_sibling
+
+    return False

src/black/parsing.py

@@ -5,7 +5,7 @@
 import ast
 import sys
 import warnings
-from typing import Collection, Iterator
+from collections.abc import Collection, Iterator
 
 from black.mode import VERSION_TO_FEATURES, Feature, TargetVersion, supports_feature
 from black.nodes import syms
@@ -213,7 +213,7 @@ def _stringify_ast(node: ast.AST, parent_stack: list[ast.AST]) -> Iterator[str]:
                     and isinstance(node, ast.Delete)
                     and isinstance(item, ast.Tuple)
                 ):
-                    for elt in item.elts:
+                    for elt in _unwrap_tuples(item):
                         yield from _stringify_ast_with_new_parent(
                             elt, parent_stack, node
                         )
@@ -250,3 +250,11 @@ def _stringify_ast(node: ast.AST, parent_stack: list[ast.AST]) -> Iterator[str]:
             )
 
     yield f"{'    ' * len(parent_stack)})  # /{node.__class__.__name__}"
+
+
+def _unwrap_tuples(node: ast.Tuple) -> Iterator[ast.AST]:
+    for elt in node.elts:
+        if isinstance(elt, ast.Tuple):
+            yield from _unwrap_tuples(elt)
+        else:
+            yield elt

src/black/ranges.py

@@ -1,8 +1,9 @@
 """Functions related to Black's formatting by line ranges feature."""
 
 import difflib
+from collections.abc import Collection, Iterator, Sequence
 from dataclasses import dataclass
-from typing import Collection, Iterator, Sequence, Union
+from typing import Union
 
 from black.nodes import (
     LN,

src/black/resources/black.schema.json

@@ -79,19 +79,12 @@
       "type": "array",
       "items": {
         "enum": [
-          "hex_codes_in_unicode_sequences",
           "string_processing",
           "hug_parens_with_braces_and_square_brackets",
-          "unify_docstring_detection",
-          "no_normalize_fmt_skip_whitespace",
           "wrap_long_dict_values_in_parens",
           "multiline_string_handling",
-          "typed_params_trailing_comma",
-          "is_simple_lookup_for_doublestar_expression",
-          "docstring_check_for_newline",
-          "remove_redundant_guard_parens",
-          "parens_for_long_if_clauses_in_case_block",
-          "pep646_typed_star_arg_type_var_tuple"
+          "always_one_newline_after_import",
+          "fix_fmt_skip_in_one_liners"
         ]
       },
       "description": "Enable specific features included in the `--unstable` style. Requires `--preview`. No compatibility guarantees are provided on the behavior or existence of any unstable features."

src/black/strings.py

@@ -5,7 +5,8 @@
 import re
 import sys
 from functools import lru_cache
-from typing import Final, Match, Pattern
+from re import Match, Pattern
+from typing import Final
 
 from black._width_table import WIDTH_TABLE
 from blib2to3.pytree import Leaf
@@ -62,10 +63,9 @@ def lines_with_leading_tabs_expanded(s: str) -> list[str]:
     return lines
 
 
-def fix_docstring(docstring: str, prefix: str) -> str:
+def fix_multiline_docstring(docstring: str, prefix: str) -> str:
     # https://www.python.org/dev/peps/pep-0257/#handling-docstring-indentation
-    if not docstring:
-        return ""
+    assert docstring, "INTERNAL ERROR: Multiline docstrings cannot be empty"
     lines = lines_with_leading_tabs_expanded(docstring)
     # Determine minimum indentation (first line doesn't count):
     indent = sys.maxsize
@@ -185,8 +185,7 @@ def normalize_string_quotes(s: str) -> str:
         orig_quote = "'"
         new_quote = '"'
     first_quote_pos = s.find(orig_quote)
-    if first_quote_pos == -1:
-        return s  # There's an internal error
+    assert first_quote_pos != -1, f"INTERNAL ERROR: Malformed string {s!r}"
 
     prefix = s[:first_quote_pos]
     unescaped_new_quote = _cached_compile(rf"(([^\\]|^)(\\\\)*){new_quote}")

src/black/trans.py

@@ -5,27 +5,15 @@
 import re
 from abc import ABC, abstractmethod
 from collections import defaultdict
+from collections.abc import Callable, Collection, Iterable, Iterator, Sequence
 from dataclasses import dataclass
-from typing import (
-    Any,
-    Callable,
-    ClassVar,
-    Collection,
-    Final,
-    Iterable,
-    Iterator,
-    Literal,
-    Optional,
-    Sequence,
-    TypeVar,
-    Union,
-)
+from typing import Any, ClassVar, Final, Literal, Optional, TypeVar, Union
 
 from mypy_extensions import trait
 
 from black.comments import contains_pragma_comment
 from black.lines import Line, append_leaves
-from black.mode import Feature, Mode, Preview
+from black.mode import Feature, Mode
 from black.nodes import (
     CLOSING_BRACKETS,
     OPENING_BRACKETS,
@@ -94,18 +82,12 @@ def is_simple_lookup(index: int, kind: Literal[1, -1]) -> bool:
         # Brackets and parentheses indicate calls, subscripts, etc. ...
         # basically stuff that doesn't count as "simple". Only a NAME lookup
         # or dotted lookup (eg. NAME.NAME) is OK.
-        if Preview.is_simple_lookup_for_doublestar_expression not in mode:
-            return original_is_simple_lookup_func(line, index, kind)
-
+        if kind == -1:
+            return handle_is_simple_look_up_prev(line, index, {token.RPAR, token.RSQB})
         else:
-            if kind == -1:
-                return handle_is_simple_look_up_prev(
-                    line, index, {token.RPAR, token.RSQB}
-                )
-            else:
-                return handle_is_simple_lookup_forward(
-                    line, index, {token.LPAR, token.LSQB}
-                )
+            return handle_is_simple_lookup_forward(
+                line, index, {token.LPAR, token.LSQB}
+            )
 
     def is_simple_operand(index: int, kind: Literal[1, -1]) -> bool:
         # An operand is considered "simple" if's a NAME, a numeric CONSTANT, a simple
@@ -151,30 +133,6 @@ def is_simple_operand(index: int, kind: Literal[1, -1]) -> bool:
     yield new_line
 
 
-def original_is_simple_lookup_func(
-    line: Line, index: int, step: Literal[1, -1]
-) -> bool:
-    if step == -1:
-        disallowed = {token.RPAR, token.RSQB}
-    else:
-        disallowed = {token.LPAR, token.LSQB}
-
-    while 0 <= index < len(line.leaves):
-        current = line.leaves[index]
-        if current.type in disallowed:
-            return False
-        if current.type not in {token.NAME, token.DOT} or current.value == "for":
-            # If the current token isn't disallowed, we'll assume this is
-            # simple as only the disallowed tokens are semantically
-            # attached to this lookup expression we're checking. Also,
-            # stop early if we hit the 'for' bit of a comprehension.
-            return True
-
-        index += step
-
-    return True
-
-
 def handle_is_simple_look_up_prev(line: Line, index: int, disallowed: set[int]) -> bool:
     """
     Handling the determination of is_simple_lookup for the lines prior to the doublestar
@@ -672,10 +630,10 @@ def make_naked(string: str, string_prefix: str) -> str:
             """
             assert_is_leaf_string(string)
             if "f" in string_prefix:
-                f_expressions = (
+                f_expressions = [
                     string[span[0] + 1 : span[1] - 1]  # +-1 to get rid of curly braces
                     for span in iter_fexpr_spans(string)
-                )
+                ]
                 debug_expressions_contain_visible_quotes = any(
                     re.search(r".*[\'\"].*(?<![!:=])={1}(?!=)(?![^\s:])", expression)
                     for expression in f_expressions
@@ -806,6 +764,8 @@ def _validate_msg(line: Line, string_idx: int) -> TResult[None]:
                 - The set of all string prefixes in the string group is of
                   length greater than one and is not equal to {"", "f"}.
                 - The string group consists of raw strings.
+                - The string group would merge f-strings with different quote types
+                  and internal quotes.
                 - The string group is stringified type annotations. We don't want to
                   process stringified type annotations since pyright doesn't support
                   them spanning multiple string values. (NOTE: mypy, pytype, pyre do
@@ -832,6 +792,8 @@ def _validate_msg(line: Line, string_idx: int) -> TResult[None]:
 
                 i += inc
 
+        QUOTE = line.leaves[string_idx].value[-1]
+
         num_of_inline_string_comments = 0
         set_of_prefixes = set()
         num_of_strings = 0
@@ -854,6 +816,19 @@ def _validate_msg(line: Line, string_idx: int) -> TResult[None]:
 
             set_of_prefixes.add(prefix)
 
+            if (
+                "f" in prefix
+                and leaf.value[-1] != QUOTE
+                and (
+                    "'" in leaf.value[len(prefix) + 1 : -1]
+                    or '"' in leaf.value[len(prefix) + 1 : -1]
+                )
+            ):
+                return TErr(
+                    "StringMerger does NOT merge f-strings with different quote types"
+                    " and internal quotes."
+                )
+
             if id(leaf) in line.comments:
                 num_of_inline_string_comments += 1
                 if contains_pragma_comment(line.comments[id(leaf)]):
@@ -882,6 +857,7 @@ class StringParenStripper(StringTransformer):
         The line contains a string which is surrounded by parentheses and:
             - The target string is NOT the only argument to a function call.
             - The target string is NOT a "pointless" string.
+            - The target string is NOT a dictionary value.
             - If the target string contains a PERCENT, the brackets are not
               preceded or followed by an operator with higher precedence than
               PERCENT.
@@ -929,11 +905,14 @@ def do_match(self, line: Line) -> TMatchResult:
             ):
                 continue
 
-            # That LPAR should NOT be preceded by a function name or a closing
-            # bracket (which could be a function which returns a function or a
-            # list/dictionary that contains a function)...
+            # That LPAR should NOT be preceded by a colon (which could be a
+            # dictionary value), function name, or a closing bracket (which
+            # could be a function returning a function or a list/dictionary
+            # containing a function)...
             if is_valid_index(idx - 2) and (
-                LL[idx - 2].type == token.NAME or LL[idx - 2].type in CLOSING_BRACKETS
+                LL[idx - 2].type == token.COLON
+                or LL[idx - 2].type == token.NAME
+                or LL[idx - 2].type in CLOSING_BRACKETS
             ):
                 continue
 
@@ -2259,12 +2238,12 @@ def do_transform(
             elif right_leaves and right_leaves[-1].type == token.RPAR:
                 # Special case for lambda expressions as dict's value, e.g.:
                 #     my_dict = {
-                #        "key": lambda x: f"formatted: {x},
+                #        "key": lambda x: f"formatted: {x}",
                 #     }
                 # After wrapping the dict's value with parentheses, the string is
                 # followed by a RPAR but its opening bracket is lambda's, not
                 # the string's:
-                #        "key": (lambda x: f"formatted: {x}),
+                #        "key": (lambda x: f"formatted: {x}"),
                 opening_bracket = right_leaves[-1].opening_bracket
                 if opening_bracket is not None and opening_bracket in left_leaves:
                     index = left_leaves.index(opening_bracket)

src/blackd/__init__.py

@@ -2,7 +2,7 @@
 import logging
 from concurrent.futures import Executor, ProcessPoolExecutor
 from datetime import datetime, timezone
-from functools import partial
+from functools import cache, partial
 from multiprocessing import freeze_support
 
 try:
@@ -85,12 +85,16 @@ def main(bind_host: str, bind_port: int) -> None:
     web.run_app(app, host=bind_host, port=bind_port, handle_signals=True, print=None)
 
 
+@cache
+def executor() -> Executor:
+    return ProcessPoolExecutor()
+
+
 def make_app() -> web.Application:
     app = web.Application(
         middlewares=[cors(allow_headers=(*BLACK_HEADERS, "Content-Type"))]
     )
-    executor = ProcessPoolExecutor()
-    app.add_routes([web.post("/", partial(handle, executor=executor))])
+    app.add_routes([web.post("/", partial(handle, executor=executor()))])
     return app
 
 

src/blackd/middlewares.py

@@ -1,4 +1,4 @@
-from typing import Awaitable, Callable, Iterable
+from collections.abc import Awaitable, Callable, Iterable
 
 from aiohttp.typedefs import Middleware
 from aiohttp.web_middlewares import middleware

src/blib2to3/Grammar.txt

@@ -12,9 +12,9 @@ file_input: (NEWLINE | stmt)* ENDMARKER
 single_input: NEWLINE | simple_stmt | compound_stmt NEWLINE
 eval_input: testlist NEWLINE* ENDMARKER
 
-typevar: NAME [':' expr] ['=' expr]
-paramspec: '**' NAME ['=' expr]
-typevartuple: '*' NAME ['=' (expr|star_expr)]
+typevar: NAME [':' test] ['=' test]
+paramspec: '**' NAME ['=' test]
+typevartuple: '*' NAME ['=' (test|star_expr)]
 typeparam: typevar | paramspec | typevartuple
 typeparams: '[' typeparam (',' typeparam)* [','] ']'
 

src/blib2to3/pgen2/driver.py

@@ -21,13 +21,14 @@
 import os
 import pkgutil
 import sys
+from collections.abc import Iterable, Iterator
 from contextlib import contextmanager
 from dataclasses import dataclass, field
 from logging import Logger
-from typing import IO, Any, Iterable, Iterator, Optional, Union, cast
+from typing import IO, Any, Optional, Union, cast
 
 from blib2to3.pgen2.grammar import Grammar
-from blib2to3.pgen2.tokenize import GoodTokenInfo
+from blib2to3.pgen2.tokenize import TokenInfo
 from blib2to3.pytree import NL
 
 # Pgen imports
@@ -111,7 +112,7 @@ def __init__(self, grammar: Grammar, logger: Optional[Logger] = None) -> None:
             logger = logging.getLogger(__name__)
         self.logger = logger
 
-    def parse_tokens(self, tokens: Iterable[GoodTokenInfo], debug: bool = False) -> NL:
+    def parse_tokens(self, tokens: Iterable[TokenInfo], debug: bool = False) -> NL:
         """Parse a series of tokens and return the syntax tree."""
         # XXX Move the prefix computation into a wrapper around tokenize.
         proxy = TokenProxy(tokens)
@@ -179,27 +180,17 @@ def parse_tokens(self, tokens: Iterable[GoodTokenInfo], debug: bool = False) ->
         assert p.rootnode is not None
         return p.rootnode
 
-    def parse_stream_raw(self, stream: IO[str], debug: bool = False) -> NL:
-        """Parse a stream and return the syntax tree."""
-        tokens = tokenize.generate_tokens(stream.readline, grammar=self.grammar)
-        return self.parse_tokens(tokens, debug)
-
-    def parse_stream(self, stream: IO[str], debug: bool = False) -> NL:
-        """Parse a stream and return the syntax tree."""
-        return self.parse_stream_raw(stream, debug)
-
     def parse_file(
         self, filename: Path, encoding: Optional[str] = None, debug: bool = False
     ) -> NL:
         """Parse a file and return the syntax tree."""
         with open(filename, encoding=encoding) as stream:
-            return self.parse_stream(stream, debug)
+            text = stream.read()
+        return self.parse_string(text, debug)
 
     def parse_string(self, text: str, debug: bool = False) -> NL:
         """Parse a string and return the syntax tree."""
-        tokens = tokenize.generate_tokens(
-            io.StringIO(text).readline, grammar=self.grammar
-        )
+        tokens = tokenize.tokenize(text, grammar=self.grammar)
         return self.parse_tokens(tokens, debug)
 
     def _partially_consume_prefix(self, prefix: str, column: int) -> tuple[str, str]:

src/blib2to3/pgen2/literals.py

@@ -4,7 +4,6 @@
 """Safely evaluate Python string literals without using eval()."""
 
 import re
-from typing import Match
 
 simple_escapes: dict[str, str] = {
     "a": "\a",
@@ -20,7 +19,7 @@
 }
 
 
-def escape(m: Match[str]) -> str:
+def escape(m: re.Match[str]) -> str:
     all, tail = m.group(0, 1)
     assert all.startswith("\\")
     esc = simple_escapes.get(tail)
@@ -29,16 +28,16 @@ def escape(m: Match[str]) -> str:
     if tail.startswith("x"):
         hexes = tail[1:]
         if len(hexes) < 2:
-            raise ValueError("invalid hex string escape ('\\%s')" % tail)
+            raise ValueError(f"invalid hex string escape ('\\{tail}')")
         try:
             i = int(hexes, 16)
         except ValueError:
-            raise ValueError("invalid hex string escape ('\\%s')" % tail) from None
+            raise ValueError(f"invalid hex string escape ('\\{tail}')") from None
     else:
         try:
             i = int(tail, 8)
         except ValueError:
-            raise ValueError("invalid octal string escape ('\\%s')" % tail) from None
+            raise ValueError(f"invalid octal string escape ('\\{tail}')") from None
     return chr(i)
 
 

src/blib2to3/pgen2/parse.py

@@ -9,8 +9,9 @@
 how this parsing engine works.
 
 """
+from collections.abc import Callable, Iterator
 from contextlib import contextmanager
-from typing import TYPE_CHECKING, Any, Callable, Iterator, Optional, Union, cast
+from typing import TYPE_CHECKING, Any, Optional, Union, cast
 
 from blib2to3.pgen2.grammar import Grammar
 from blib2to3.pytree import NL, Context, Leaf, Node, RawNode, convert
@@ -88,18 +89,12 @@ def backtrack(self) -> Iterator[None]:
             self.parser.is_backtracking = is_backtracking
 
     def add_token(self, tok_type: int, tok_val: str, raw: bool = False) -> None:
-        func: Callable[..., Any]
-        if raw:
-            func = self.parser._addtoken
-        else:
-            func = self.parser.addtoken
-
         for ilabel in self.ilabels:
             with self.switch_to(ilabel):
-                args = [tok_type, tok_val, self.context]
                 if raw:
-                    args.insert(0, ilabel)
-                func(*args)
+                    self.parser._addtoken(ilabel, tok_type, tok_val, self.context)
+                else:
+                    self.parser.addtoken(tok_type, tok_val, self.context)
 
     def determine_route(
         self, value: Optional[str] = None, force: bool = False

src/blib2to3/pgen2/pgen.py

@@ -2,10 +2,11 @@
 # Licensed to PSF under a Contributor Agreement.
 
 import os
-from typing import IO, Any, Iterator, NoReturn, Optional, Sequence, Union
+from collections.abc import Iterator, Sequence
+from typing import IO, Any, NoReturn, Optional, Union
 
 from blib2to3.pgen2 import grammar, token, tokenize
-from blib2to3.pgen2.tokenize import GoodTokenInfo
+from blib2to3.pgen2.tokenize import TokenInfo
 
 Path = Union[str, "os.PathLike[str]"]
 
@@ -17,7 +18,7 @@ class PgenGrammar(grammar.Grammar):
 class ParserGenerator:
     filename: Path
     stream: IO[str]
-    generator: Iterator[GoodTokenInfo]
+    generator: Iterator[TokenInfo]
     first: dict[str, Optional[dict[str, int]]]
 
     def __init__(self, filename: Path, stream: Optional[IO[str]] = None) -> None:
@@ -26,8 +27,7 @@ def __init__(self, filename: Path, stream: Optional[IO[str]] = None) -> None:
             stream = open(filename, encoding="utf-8")
             close_stream = stream.close
         self.filename = filename
-        self.stream = stream
-        self.generator = tokenize.generate_tokens(stream.readline)
+        self.generator = tokenize.tokenize(stream.read())
         self.gettoken()  # Initialize lookahead
         self.dfas, self.startsymbol = self.parse()
         if close_stream is not None:
@@ -140,7 +140,7 @@ def calcfirst(self, name: str) -> None:
                 if label in self.first:
                     fset = self.first[label]
                     if fset is None:
-                        raise ValueError("recursion for rule %r" % name)
+                        raise ValueError(f"recursion for rule {name!r}")
                 else:
                     self.calcfirst(label)
                     fset = self.first[label]
@@ -155,8 +155,8 @@ def calcfirst(self, name: str) -> None:
             for symbol in itsfirst:
                 if symbol in inverse:
                     raise ValueError(
-                        "rule %s is ambiguous; %s is in the first sets of %s as well"
-                        " as %s" % (name, symbol, label, inverse[symbol])
+                        f"rule {name} is ambiguous; {symbol} is in the first sets of"
+                        f" {label} as well as {inverse[symbol]}"
                     )
                 inverse[symbol] = label
         self.first[name] = totalset
@@ -237,16 +237,16 @@ def dump_nfa(self, name: str, start: "NFAState", finish: "NFAState") -> None:
                     j = len(todo)
                     todo.append(next)
                 if label is None:
-                    print("    -> %d" % j)
+                    print(f"    -> {j}")
                 else:
-                    print("    %s -> %d" % (label, j))
+                    print(f"    {label} -> {j}")
 
     def dump_dfa(self, name: str, dfa: Sequence["DFAState"]) -> None:
         print("Dump of DFA for", name)
         for i, state in enumerate(dfa):
             print("  State", i, state.isfinal and "(final)" or "")
             for label, next in sorted(state.arcs.items()):
-                print("    %s -> %d" % (label, dfa.index(next)))
+                print(f"    {label} -> {dfa.index(next)}")
 
     def simplify_dfa(self, dfa: list["DFAState"]) -> None:
         # This is not theoretically optimal, but works well enough.
@@ -330,15 +330,12 @@ def parse_atom(self) -> tuple["NFAState", "NFAState"]:
             return a, z
         else:
             self.raise_error(
-                "expected (...) or NAME or STRING, got %s/%s", self.type, self.value
+                f"expected (...) or NAME or STRING, got {self.type}/{self.value}"
             )
-            raise AssertionError
 
     def expect(self, type: int, value: Optional[Any] = None) -> str:
         if self.type != type or (value is not None and self.value != value):
-            self.raise_error(
-                "expected %s/%s, got %s/%s", type, value, self.type, self.value
-            )
+            self.raise_error(f"expected {type}/{value}, got {self.type}/{self.value}")
         value = self.value
         self.gettoken()
         return value
@@ -350,13 +347,10 @@ def gettoken(self) -> None:
         self.type, self.value, self.begin, self.end, self.line = tup
         # print token.tok_name[self.type], repr(self.value)
 
-    def raise_error(self, msg: str, *args: Any) -> NoReturn:
-        if args:
-            try:
-                msg = msg % args
-            except Exception:
-                msg = " ".join([msg] + list(map(str, args)))
-        raise SyntaxError(msg, (self.filename, self.end[0], self.end[1], self.line))
+    def raise_error(self, msg: str) -> NoReturn:
+        raise SyntaxError(
+            msg, (str(self.filename), self.end[0], self.end[1], self.line)
+        )
 
 
 class NFAState:

src/blib2to3/pytree.py

@@ -12,7 +12,8 @@
 
 # mypy: allow-untyped-defs, allow-incomplete-defs
 
-from typing import Any, Iterable, Iterator, Optional, TypeVar, Union
+from collections.abc import Iterable, Iterator
+from typing import Any, Optional, TypeVar, Union
 
 from blib2to3.pgen2.grammar import Grammar
 
@@ -267,11 +268,7 @@ def __init__(
     def __repr__(self) -> str:
         """Return a canonical string representation."""
         assert self.type is not None
-        return "{}({}, {!r})".format(
-            self.__class__.__name__,
-            type_repr(self.type),
-            self.children,
-        )
+        return f"{self.__class__.__name__}({type_repr(self.type)}, {self.children!r})"
 
     def __str__(self) -> str:
         """
@@ -420,10 +417,9 @@ def __repr__(self) -> str:
         from .pgen2.token import tok_name
 
         assert self.type is not None
-        return "{}({}, {!r})".format(
-            self.__class__.__name__,
-            tok_name.get(self.type, self.type),
-            self.value,
+        return (
+            f"{self.__class__.__name__}({tok_name.get(self.type, self.type)},"
+            f" {self.value!r})"
         )
 
     def __str__(self) -> str:
@@ -526,7 +522,7 @@ def __repr__(self) -> str:
         args = [type_repr(self.type), self.content, self.name]
         while args and args[-1] is None:
             del args[-1]
-        return "{}({})".format(self.__class__.__name__, ", ".join(map(repr, args)))
+        return f"{self.__class__.__name__}({', '.join(map(repr, args))})"
 
     def _submatch(self, node, results=None) -> bool:
         raise NotImplementedError

tests/data/cases/annotations.py

@@ -0,0 +1,17 @@
+# regression test for #1765
+class Foo:
+    def foo(self):
+        if True:
+            content_ids: Mapping[
+                str, Optional[ContentId]
+            ] = self.publisher_content_store.store_config_contents(files)
+
+# output
+
+# regression test for #1765
+class Foo:
+    def foo(self):
+        if True:
+            content_ids: Mapping[str, Optional[ContentId]] = (
+                self.publisher_content_store.store_config_contents(files)
+            )

tests/data/cases/cantfit.py

@@ -1,4 +1,3 @@
-# flags: --preview
 # long variable name
 this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = 0
 this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = 1  # with a comment
@@ -32,7 +31,8 @@
         raise ValueError(err.format(key))
 concatenated_strings = "some strings that are " "concatenated implicitly, so if you put them on separate " "lines it will fit"
 del concatenated_strings, string_variable_name, normal_function_name, normal_name, need_more_to_make_the_line_long_enough
-
+del ([], name_1, name_2), [(), [], name_4, name_3], name_1[[name_2 for name_1 in name_0]]
+del (),
 
 # output
 
@@ -92,3 +92,9 @@
     normal_name,
     need_more_to_make_the_line_long_enough,
 )
+del (
+    ([], name_1, name_2),
+    [(), [], name_4, name_3],
+    name_1[[name_2 for name_1 in name_0]],
+)
+del ((),)

tests/data/cases/context_managers_38.py

@@ -1,4 +1,3 @@
-# flags: --minimum-version=3.8
 with \
      make_context_manager1() as cm1, \
      make_context_manager2() as cm2, \

tests/data/cases/context_managers_39.py

@@ -1,4 +1,3 @@
-# flags: --minimum-version=3.9
 with \
      make_context_manager1() as cm1, \
      make_context_manager2() as cm2, \
@@ -85,6 +84,31 @@ async def func():
         pass
 
 
+
+# don't remove the brackets here, it changes the meaning of the code.
+with (x, y) as z:
+    pass
+
+
+# don't remove the brackets here, it changes the meaning of the code.
+# even though the code will always trigger a runtime error
+with (name_5, name_4), name_5:
+    pass
+
+
+def test_tuple_as_contextmanager():
+    from contextlib import nullcontext
+
+    try:
+        with (nullcontext(),nullcontext()),nullcontext():
+            pass
+    except TypeError: 
+        # test passed
+        pass
+    else:
+        # this should be a type error
+        assert False
+
 # output
 
 
@@ -173,3 +197,28 @@ async def func():
         some_other_function(argument1, argument2, argument3="some_value"),
     ):
         pass
+
+
+# don't remove the brackets here, it changes the meaning of the code.
+with (x, y) as z:
+    pass
+
+
+# don't remove the brackets here, it changes the meaning of the code.
+# even though the code will always trigger a runtime error
+with (name_5, name_4), name_5:
+    pass
+
+
+def test_tuple_as_contextmanager():
+    from contextlib import nullcontext
+
+    try:
+        with (nullcontext(), nullcontext()), nullcontext():
+            pass
+    except TypeError:
+        # test passed
+        pass
+    else:
+        # this should be a type error
+        assert False

tests/data/cases/context_managers_autodetect_39.py

@@ -1,4 +1,3 @@
-# flags: --minimum-version=3.9
 # This file uses parenthesized context managers introduced in Python 3.9.
 
 

tests/data/cases/docstring_newline.py

@@ -1,4 +1,3 @@
-# flags: --preview
 """
 87 characters ............................................................................
 """

tests/data/cases/fmtskip10.py

@@ -0,0 +1,9 @@
+# flags: --preview
+def foo(): return "mock"  # fmt: skip
+if True: print("yay")  # fmt: skip
+for i in range(10): print(i)  # fmt: skip
+
+j =     1 # fmt: skip
+while j < 10: j += 1  # fmt: skip
+
+b = [c for c in "A very long string that would normally generate some kind of collapse, since it is this long"] # fmt: skip

tests/data/cases/fmtskip11.py

@@ -0,0 +1,6 @@
+def foo():
+    pass
+
+
+# comment 1  # fmt: skip
+# comment 2

tests/data/cases/fmtskip9.py

@@ -1,4 +1,3 @@
-# flags: --preview
 print () # fmt: skip
 print () # fmt:skip
 

tests/data/cases/format_unicode_escape_seq.py

@@ -1,4 +1,3 @@
-# flags: --preview
 x = "\x1F"
 x = "\\x1B"
 x = "\\\x1B"

tests/data/cases/fstring_quotations.py

@@ -0,0 +1,67 @@
+# Regression tests for long f-strings, including examples from issue #3623
+
+a = (
+    'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
+    f'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"{"b"}"'
+)
+
+a = (
+    f'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"{"b"}"'
+    'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
+)
+
+a = 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa' + \
+    f'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"{"b"}"'
+
+a = f'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"{"b"}"' + \
+    f'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"{"b"}"'
+
+a = (
+    f'bbbbbbb"{"b"}"'
+    'aaaaaaaa'
+)
+
+a = (
+    f'"{"b"}"'
+)
+
+a = (
+    f'\"{"b"}\"'
+)
+
+a = (
+    r'\"{"b"}\"'
+)
+
+# output
+
+# Regression tests for long f-strings, including examples from issue #3623
+
+a = (
+    "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    f'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"{"b"}"'
+)
+
+a = (
+    f'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"{"b"}"'
+    "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+)
+
+a = (
+    "aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+    + f'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"{"b"}"'
+)
+
+a = (
+    f'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"{"b"}"'
+    + f'bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"{"b"}"'
+)
+
+a = f'bbbbbbb"{"b"}"' "aaaaaaaa"
+
+a = f'"{"b"}"'
+
+a = f'"{"b"}"'
+
+a = r'\"{"b"}\"'
+

tests/data/cases/funcdef_return_type_trailing_comma.py

@@ -1,4 +1,4 @@
-# flags: --preview --minimum-version=3.10
+# flags: --minimum-version=3.10
 # normal, short, function definition
 def foo(a, b) -> tuple[int, float]: ...
 

tests/data/cases/generics_wrapping.py

@@ -0,0 +1,307 @@
+# flags: --minimum-version=3.12
+def plain[T, B](a: T, b: T) -> T:
+    return a
+
+def arg_magic[T, B](a: T, b: T,) -> T:
+    return a
+
+def type_param_magic[T, B,](a: T, b: T) -> T:
+    return a
+
+def both_magic[T, B,](a: T, b: T,) -> T:
+    return a
+
+
+def plain_multiline[
+    T,
+    B
+](
+    a: T,
+    b: T
+) -> T:
+    return a
+
+def arg_magic_multiline[
+    T,
+    B
+](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+def type_param_magic_multiline[
+    T,
+    B,
+](
+    a: T,
+    b: T
+) -> T:
+    return a
+
+def both_magic_multiline[
+    T,
+    B,
+](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+
+def plain_mixed1[
+    T,
+    B
+](a: T, b: T) -> T:
+    return a
+
+def plain_mixed2[T, B](
+    a: T,
+    b: T
+) -> T:
+    return a
+
+def arg_magic_mixed1[
+    T,
+    B
+](a: T, b: T,) -> T:
+    return a
+
+def arg_magic_mixed2[T, B](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+def type_param_magic_mixed1[
+    T,
+    B,
+](a: T, b: T) -> T:
+    return a
+
+def type_param_magic_mixed2[T, B,](
+    a: T,
+    b: T
+) -> T:
+    return a
+
+def both_magic_mixed1[
+    T,
+    B,
+](a: T, b: T,) -> T:
+    return a
+
+def both_magic_mixed2[T, B,](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+def something_something_function[
+    T: Model
+](param: list[int], other_param: type[T], *, some_other_param: bool = True) -> QuerySet[
+    T
+]:
+    pass
+
+
+def func[A_LOT_OF_GENERIC_TYPES: AreBeingDefinedHere, LIKE_THIS, AND_THIS, ANOTHER_ONE, AND_YET_ANOTHER_ONE: ThisOneHasTyping](a: T, b: T, c: T, d: T, e: T, f: T, g: T, h: T, i: T, j: T, k: T, l: T, m: T, n: T, o: T, p: T) -> T:
+    return a
+
+
+def with_random_comments[
+    Z
+    # bye
+]():
+    return a
+
+
+def func[
+    T,  # comment
+    U  # comment
+    ,
+    Z:  # comment
+    int
+](): pass
+
+
+def func[
+    T,  # comment but it's long so it doesn't just move to the end of the line
+    U  # comment comment comm comm ent ent
+    ,
+    Z:  # comment ent ent comm comm comment
+    int
+](): pass
+
+
+# output
+def plain[T, B](a: T, b: T) -> T:
+    return a
+
+
+def arg_magic[T, B](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+
+def type_param_magic[
+    T,
+    B,
+](
+    a: T, b: T
+) -> T:
+    return a
+
+
+def both_magic[
+    T,
+    B,
+](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+
+def plain_multiline[T, B](a: T, b: T) -> T:
+    return a
+
+
+def arg_magic_multiline[T, B](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+
+def type_param_magic_multiline[
+    T,
+    B,
+](
+    a: T, b: T
+) -> T:
+    return a
+
+
+def both_magic_multiline[
+    T,
+    B,
+](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+
+def plain_mixed1[T, B](a: T, b: T) -> T:
+    return a
+
+
+def plain_mixed2[T, B](a: T, b: T) -> T:
+    return a
+
+
+def arg_magic_mixed1[T, B](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+
+def arg_magic_mixed2[T, B](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+
+def type_param_magic_mixed1[
+    T,
+    B,
+](
+    a: T, b: T
+) -> T:
+    return a
+
+
+def type_param_magic_mixed2[
+    T,
+    B,
+](
+    a: T, b: T
+) -> T:
+    return a
+
+
+def both_magic_mixed1[
+    T,
+    B,
+](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+
+def both_magic_mixed2[
+    T,
+    B,
+](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+
+def something_something_function[T: Model](
+    param: list[int], other_param: type[T], *, some_other_param: bool = True
+) -> QuerySet[T]:
+    pass
+
+
+def func[
+    A_LOT_OF_GENERIC_TYPES: AreBeingDefinedHere,
+    LIKE_THIS,
+    AND_THIS,
+    ANOTHER_ONE,
+    AND_YET_ANOTHER_ONE: ThisOneHasTyping,
+](
+    a: T,
+    b: T,
+    c: T,
+    d: T,
+    e: T,
+    f: T,
+    g: T,
+    h: T,
+    i: T,
+    j: T,
+    k: T,
+    l: T,
+    m: T,
+    n: T,
+    o: T,
+    p: T,
+) -> T:
+    return a
+
+
+def with_random_comments[
+    Z
+    # bye
+]():
+    return a
+
+
+def func[T, U, Z: int]():  # comment  # comment  # comment
+    pass
+
+
+def func[
+    T,  # comment but it's long so it doesn't just move to the end of the line
+    U,  # comment comment comm comm ent ent
+    Z: int,  # comment ent ent comm comm comment
+]():
+    pass

tests/data/cases/is_simple_lookup_for_doublestar_expression.py

@@ -1,4 +1,3 @@
-# flags: --preview
 m2 = None if not isinstance(dist, Normal) else m** 2 + s * 2
 m3 = None if not isinstance(dist, Normal) else m ** 2 + s * 2
 m4 = None if not isinstance(dist, Normal) else m**2 + s * 2

tests/data/cases/long_strings__type_annotations.py

@@ -1,4 +1,3 @@
-# flags: --preview
 def func(
     arg1,
     arg2,

tests/data/cases/module_docstring_2.py

@@ -1,7 +1,6 @@
-# flags: --preview
 """I am a very helpful module docstring.
 
-With trailing spaces (only removed with unify_docstring_detection on):      
+With trailing spaces:      
 Lorem ipsum dolor sit amet, consectetur adipiscing elit,
 sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
 Ut enim ad minim veniam,
@@ -39,7 +38,7 @@
 # output
 """I am a very helpful module docstring.
 
-With trailing spaces (only removed with unify_docstring_detection on):
+With trailing spaces:
 Lorem ipsum dolor sit amet, consectetur adipiscing elit,
 sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
 Ut enim ad minim veniam,

tests/data/cases/no_blank_line_before_docstring.py

@@ -62,5 +62,4 @@ class MultilineDocstringsAsWell:
 
 
 class SingleQuotedDocstring:
-
     "I'm a docstring but I don't even get triple quotes."

tests/data/cases/pattern_matching_with_if_stmt.py

@@ -1,4 +1,4 @@
-# flags: --preview --minimum-version=3.10
+# flags: --minimum-version=3.10
 match match:
     case "test" if case != "not very loooooooooooooog condition":  # comment
         pass

tests/data/cases/pep646_typed_star_arg_type_var_tuple.py

@@ -1,4 +1,4 @@
-# flags: --minimum-version=3.11 --preview
+# flags: --minimum-version=3.11
 
 
 def fn(*args: *tuple[*A, B]) -> None:

tests/data/cases/pep_570.py

@@ -1,4 +1,3 @@
-# flags: --minimum-version=3.8
 def positional_only_arg(a, /):
     pass
 

tests/data/cases/pep_572.py

@@ -1,4 +1,3 @@
-# flags: --minimum-version=3.8
 (a := 1)
 (a := a)
 if (match := pattern.search(data)) is None:

tests/data/cases/pep_572_py310.py

@@ -14,3 +14,8 @@
 f((a := b + c for c in range(10)), x)
 f(y=(a := b + c for c in range(10)))
 f(x, (a := b + c for c in range(10)), y=z, **q)
+
+
+# Don't remove parens when assignment expr is one of the exprs in a with statement
+with x, (a := b):
+    pass

tests/data/cases/pep_572_py39.py

@@ -1,4 +1,3 @@
-# flags: --minimum-version=3.9
 # Unparenthesized walruses are now allowed in set literals & set comprehensions
 # since Python 3.9
 {x := 1, 2, 3}

tests/data/cases/pep_572_remove_parens.py

@@ -1,4 +1,3 @@
-# flags: --minimum-version=3.8
 if (foo := 0):
     pass
 

tests/data/cases/prefer_rhs_split_reformatted.py

@@ -11,6 +11,14 @@
 # exactly line length limit + 1, it won't be split like that.
 xxxxxxxxx_yyy_zzzzzzzz[xx.xxxxxx(x_yyy_zzzzzz.xxxxx[0]), x_yyy_zzzzzz.xxxxxx(xxxx=1)] = 1
 
+# Regression test for #1187
+print(
+    dict(
+        a=1,
+        b=2 if some_kind_of_data is not None else some_other_kind_of_data,  # some explanation of why this is actually necessary
+        c=3,
+    )
+)
 
 # output
 
@@ -36,3 +44,14 @@
 xxxxxxxxx_yyy_zzzzzzzz[
     xx.xxxxxx(x_yyy_zzzzzz.xxxxx[0]), x_yyy_zzzzzz.xxxxxx(xxxx=1)
 ] = 1
+
+# Regression test for #1187
+print(
+    dict(
+        a=1,
+        b=(
+            2 if some_kind_of_data is not None else some_other_kind_of_data
+        ),  # some explanation of why this is actually necessary
+        c=3,
+    )
+)

tests/data/cases/preview_comments7.py

@@ -177,7 +177,6 @@ def test_fails_invalid_post_data(
     MyLovelyCompanyTeamProjectComponent as component,  # DRY
 )
 
-
 result = 1  # look ma, no comment migration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
 
 result = 1  # look ma, no comment migration xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

tests/data/cases/preview_fstring.py

@@ -0,0 +1,2 @@
+# flags: --unstable
+f"{''=}" f'{""=}'

tests/data/cases/preview_import_line_collapse.py

@@ -0,0 +1,180 @@
+# flags: --preview
+from middleman.authentication import validate_oauth_token
+
+
+logger = logging.getLogger(__name__)
+
+
+# case 2 comment after import
+from middleman.authentication import validate_oauth_token
+#comment
+
+logger = logging.getLogger(__name__)
+
+
+# case 3 comment after import
+from middleman.authentication import validate_oauth_token
+# comment
+logger = logging.getLogger(__name__)
+
+
+from middleman.authentication import validate_oauth_token
+
+
+
+logger = logging.getLogger(__name__)
+
+
+# case 4 try catch with import after import
+import os
+import os
+
+
+
+try:
+    import os
+except Exception:
+    pass
+
+try:
+    import os
+    def func():
+        a = 1
+except Exception:
+    pass
+
+
+# case 5 multiple imports
+import os
+import os
+
+import os
+import os
+
+
+
+
+
+for i in range(10):
+    print(i)
+
+
+# case 6 import in function
+def func():
+    print()
+    import os
+    def func():
+        pass
+    print()
+
+
+def func():
+    import os
+    a = 1
+    print()
+
+
+def func():
+    import os
+
+
+    a = 1
+    print()
+
+
+def func():
+    import os
+
+
+
+    a = 1
+    print()
+
+# output
+
+
+from middleman.authentication import validate_oauth_token
+
+logger = logging.getLogger(__name__)
+
+
+# case 2 comment after import
+from middleman.authentication import validate_oauth_token
+
+# comment
+
+logger = logging.getLogger(__name__)
+
+
+# case 3 comment after import
+from middleman.authentication import validate_oauth_token
+
+# comment
+logger = logging.getLogger(__name__)
+
+
+from middleman.authentication import validate_oauth_token
+
+logger = logging.getLogger(__name__)
+
+
+# case 4 try catch with import after import
+import os
+import os
+
+try:
+    import os
+except Exception:
+    pass
+
+try:
+    import os
+
+    def func():
+        a = 1
+
+except Exception:
+    pass
+
+
+# case 5 multiple imports
+import os
+import os
+
+import os
+import os
+
+for i in range(10):
+    print(i)
+
+
+# case 6 import in function
+def func():
+    print()
+    import os
+
+    def func():
+        pass
+
+    print()
+
+
+def func():
+    import os
+
+    a = 1
+    print()
+
+
+def func():
+    import os
+
+    a = 1
+    print()
+
+
+def func():
+    import os
+
+    a = 1
+    print()

tests/data/cases/preview_long_dict_values.py

@@ -1,4 +1,25 @@
-# flags: --unstable
+# flags: --preview
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": (
+        "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxx{xx}xxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx"
+    )
+}
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": (
+        "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxx{xx}xxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx"
+    ),
+}
+x = {
+    "foo": bar,
+    "foo": bar,
+    "foo": (
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    ),
+}
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxx"
+}
+
 my_dict = {
     "something_something":
         r"Lorem ipsum dolor sit amet, an sed convenire eloquentiam \t"
@@ -6,23 +27,90 @@
         r"signiferumque, duo ea vocibus consetetur scriptorem. Facer \t",
 }
 
+# Function calls as keys
+tasks = {
+    get_key_name(
+        foo,
+        bar,
+        baz,
+    ): src,
+    loop.run_in_executor(): src,
+    loop.run_in_executor(xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx): src,
+    loop.run_in_executor(
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxx
+    ): src,
+    loop.run_in_executor(): (
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    ),
+}
+
+# Dictionary comprehensions
+tasks = {
+    key_name: (
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    )
+    for src in sources
+}
+tasks = {key_name: foobar for src in sources}
+tasks = {
+    get_key_name(
+        src,
+    ): "foo"
+    for src in sources
+}
+tasks = {
+    get_key_name(
+        foo,
+        bar,
+        baz,
+    ): src
+    for src in sources
+}
+tasks = {
+    get_key_name(): (
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    )
+    for src in sources
+}
+tasks = {get_key_name(): foobar for src in sources}
+
+
+# Delimiters inside the value
+def foo():
+    def bar():
+        x = {
+            common.models.DateTimeField: datetime(2020, 1, 31, tzinfo=utc) + timedelta(
+                days=i
+            ),
+        }
+        x = {
+            common.models.DateTimeField: (
+                datetime(2020, 1, 31, tzinfo=utc) + timedelta(days=i)
+            ),
+        }
+        x = {
+            "foobar": (123 + 456),
+        }
+        x = {
+            "foobar": (123) + 456,
+        }
+
+
 my_dict = {
     "a key in my dict": a_very_long_variable * and_a_very_long_function_call() / 100000.0
 }
-
 my_dict = {
     "a key in my dict": a_very_long_variable * and_a_very_long_function_call() * and_another_long_func() / 100000.0
 }
-
 my_dict = {
     "a key in my dict": MyClass.some_attribute.first_call().second_call().third_call(some_args="some value")
 }
 
 {
-    'xxxxxx':
+    "xxxxxx":
         xxxxxxxxxxxxxxxxxxx.xxxxxxxxxxxxxx(
             xxxxxxxxxxxxxx={
-                'x':
+                "x":
                     xxxxxxxxxxxxxxxxxxxxxxxxxx.xxxxxxxxxxxxxxxxxxxxxxxxxxxxx(
                         xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx=(
                             xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
@@ -30,8 +118,8 @@
                                 xxxxxxxxxxxxx=xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
                                 .xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx(
                                     xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx={
-                                        'x': x.xx,
-                                        'x': x.x,
+                                        "x": x.xx,
+                                        "x": x.x,
                                     }))))
             }),
 }
@@ -58,7 +146,26 @@ def func():
 
 
 # output
-
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": (
+        "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxx{xx}xxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx"
+    )
+}
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": (
+        "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxx{xx}xxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx"
+    ),
+}
+x = {
+    "foo": bar,
+    "foo": bar,
+    "foo": (
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    ),
+}
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxx"
+}
 
 my_dict = {
     "something_something": (
@@ -68,12 +175,80 @@ def func():
     ),
 }
 
+# Function calls as keys
+tasks = {
+    get_key_name(
+        foo,
+        bar,
+        baz,
+    ): src,
+    loop.run_in_executor(): src,
+    loop.run_in_executor(xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx): src,
+    loop.run_in_executor(
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxx
+    ): src,
+    loop.run_in_executor(): (
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    ),
+}
+
+# Dictionary comprehensions
+tasks = {
+    key_name: (
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    )
+    for src in sources
+}
+tasks = {key_name: foobar for src in sources}
+tasks = {
+    get_key_name(
+        src,
+    ): "foo"
+    for src in sources
+}
+tasks = {
+    get_key_name(
+        foo,
+        bar,
+        baz,
+    ): src
+    for src in sources
+}
+tasks = {
+    get_key_name(): (
+        xx_xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxxxxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx
+    )
+    for src in sources
+}
+tasks = {get_key_name(): foobar for src in sources}
+
+
+# Delimiters inside the value
+def foo():
+    def bar():
+        x = {
+            common.models.DateTimeField: (
+                datetime(2020, 1, 31, tzinfo=utc) + timedelta(days=i)
+            ),
+        }
+        x = {
+            common.models.DateTimeField: (
+                datetime(2020, 1, 31, tzinfo=utc) + timedelta(days=i)
+            ),
+        }
+        x = {
+            "foobar": 123 + 456,
+        }
+        x = {
+            "foobar": (123) + 456,
+        }
+
+
 my_dict = {
     "a key in my dict": (
         a_very_long_variable * and_a_very_long_function_call() / 100000.0
     )
 }
-
 my_dict = {
     "a key in my dict": (
         a_very_long_variable
@@ -82,7 +257,6 @@ def func():
         / 100000.0
     )
 }
-
 my_dict = {
     "a key in my dict": (
         MyClass.some_attribute.first_call()
@@ -113,8 +287,8 @@ def func():
 
 class Random:
     def func():
-        random_service.status.active_states.inactive = (
-            make_new_top_level_state_from_dict({
+        random_service.status.active_states.inactive = make_new_top_level_state_from_dict(
+            {
                 "topLevelBase": {
                     "secondaryBase": {
                         "timestamp": 1234,
@@ -125,5 +299,5 @@ def func():
                         ),
                     }
                 },
-            })
+            }
         )

tests/data/cases/preview_long_strings.py

@@ -279,7 +279,7 @@ def foo():
     "........................................................................... \\N{LAO KO LA}"
 )
 
-msg = lambda x: f"this is a very very very long lambda value {x} that doesn't fit on a single line"
+msg = lambda x: f"this is a very very very very long lambda value {x} that doesn't fit on a single line"
 
 dict_with_lambda_values = {
     "join": lambda j: (
@@ -329,6 +329,20 @@ def foo():
 
 log.info(f"""Skipping: {'a' == 'b'} {desc['ms_name']} {money=} {dte=} {pos_share=} {desc['status']} {desc['exposure_max']}""")
 
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": (
+        "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxx{xx}xxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx"
+    )
+}
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxx{xx}xxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx",
+}
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": (
+        "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxx"
+    )
+}
+
 # output
 
 
@@ -842,11 +856,9 @@ def foo():
     " \\N{LAO KO LA}"
 )
 
-msg = (
-    lambda x: (
-        f"this is a very very very long lambda value {x} that doesn't fit on a single"
-        " line"
-    )
+msg = lambda x: (
+    f"this is a very very very very long lambda value {x} that doesn't fit on a"
+    " single line"
 )
 
 dict_with_lambda_values = {
@@ -882,7 +894,7 @@ def foo():
 
 log.info(
     "Skipping:"
-    f" {desc['db_id']} {foo('bar',x=123)} {'foo' != 'bar'} {(x := 'abc=')} {pos_share=} {desc['status']} {desc['exposure_max']}"
+    f' {desc["db_id"]} {foo("bar",x=123)} {"foo" != "bar"} {(x := "abc=")} {pos_share=} {desc["status"]} {desc["exposure_max"]}'
 )
 
 log.info(
@@ -902,7 +914,7 @@ def foo():
 
 log.info(
     "Skipping:"
-    f" {'a' == 'b' == 'c' == 'd'} {desc['ms_name']} {money=} {dte=} {pos_share=} {desc['status']} {desc['exposure_max']}"
+    f' {"a" == "b" == "c" == "d"} {desc["ms_name"]} {money=} {dte=} {pos_share=} {desc["status"]} {desc["exposure_max"]}'
 )
 
 log.info(
@@ -926,3 +938,17 @@ def foo():
 log.info(
     f"""Skipping: {'a' == 'b'} {desc['ms_name']} {money=} {dte=} {pos_share=} {desc['status']} {desc['exposure_max']}"""
 )
+
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": (
+        "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxx{xx}xxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx"
+    )
+}
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": (
+        "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxxx{xx}xxx_xxxxx_xxxxxxxxx_xxxxxxxxxxxx_xxxx"
+    ),
+}
+x = {
+    "xx_xxxxx_xxxxxxxxxx_xxxxxxxxx_xx": "xx:xxxxxxxxxxxxxxxxx_xxxxx_xxxxxxx_xxxxxxxxxx"
+}

tests/data/cases/preview_long_strings__regression.py

@@ -552,6 +552,7 @@ async def foo(self):
 }
 
 # Regression test for https://github.com/psf/black/issues/3506.
+# Regressed again by https://github.com/psf/black/pull/4498
 s = (
     "With single quote: ' "
     f" {my_dict['foo']}"
@@ -1239,9 +1240,15 @@ async def foo(self):
 }
 
 # Regression test for https://github.com/psf/black/issues/3506.
-s = f"With single quote: '  {my_dict['foo']} With double quote: \"  {my_dict['bar']}"
+# Regressed again by https://github.com/psf/black/pull/4498
+s = (
+    "With single quote: ' "
+    f" {my_dict['foo']}"
+    ' With double quote: " '
+    f' {my_dict["bar"]}'
+)
 
 s = (
     "Lorem Ipsum is simply dummy text of the printing and typesetting"
-    f" industry:'{my_dict['foo']}'"
+    f' industry:\'{my_dict["foo"]}\''
 )

tests/data/cases/preview_remove_multiline_lone_list_item_parens.py

@@ -0,0 +1,246 @@
+# flags: --unstable
+items  = [(x for x in [1])]
+
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2"}
+        if some_var == ""
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        "123456890123457890123468901234567890"
+        if some_var == "long strings"
+        else "123467890123467890"
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        and some_var == "long strings"
+        and {"key": "val"}
+    )
+]
+items = [
+    (
+        "123456890123457890123468901234567890"
+        and some_var == "long strings"
+        and "123467890123467890"
+    )
+]
+items = [
+    (
+        long_variable_name
+        and even_longer_variable_name
+        and yet_another_very_long_variable_name
+    )
+]
+
+# Shouldn't remove trailing commas
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    ),
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        and some_var == "long strings"
+        and {"key": "val"}
+    ),
+]
+items = [
+    (
+        "123456890123457890123468901234567890"
+        and some_var == "long strings"
+        and "123467890123467890"
+    ),
+]
+items = [
+    (
+        long_variable_name
+        and even_longer_variable_name
+        and yet_another_very_long_variable_name
+    ),
+]
+
+# Shouldn't add parentheses
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
+
+# Shouldn't crash with comments
+items = [
+    (  # comment
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )  # comment
+]
+
+items = [  # comment
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]  # comment
+
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}  # comment
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+
+items = [  # comment
+    (  # comment
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )  # comment
+]  # comment
+
+
+# output
+items = [(x for x in [1])]
+
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
+items = [
+    "123456890123457890123468901234567890"
+    if some_var == "long strings"
+    else "123467890123467890"
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    and some_var == "long strings"
+    and {"key": "val"}
+]
+items = [
+    "123456890123457890123468901234567890"
+    and some_var == "long strings"
+    and "123467890123467890"
+]
+items = [
+    long_variable_name
+    and even_longer_variable_name
+    and yet_another_very_long_variable_name
+]
+
+# Shouldn't remove trailing commas
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    ),
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        and some_var == "long strings"
+        and {"key": "val"}
+    ),
+]
+items = [
+    (
+        "123456890123457890123468901234567890"
+        and some_var == "long strings"
+        and "123467890123467890"
+    ),
+]
+items = [
+    (
+        long_variable_name
+        and even_longer_variable_name
+        and yet_another_very_long_variable_name
+    ),
+]
+
+# Shouldn't add parentheses
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
+
+# Shouldn't crash with comments
+items = [  # comment
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]  # comment
+
+items = [  # comment
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]  # comment
+
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}  # comment
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+
+items = [  # comment  # comment
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]
+items = [
+    {"key1": "val1", "key2": "val2", "key3": "val3"}
+    if some_var == "long strings"
+    else {"key": "val"}
+]  # comment  # comment

tests/data/cases/python37.py

@@ -1,6 +1,3 @@
-# flags: --minimum-version=3.7
-
-
 def f():
     return (i * 2 async for i in arange(42))
 
@@ -13,6 +10,7 @@ def g():
 
 
 async def func():
+    await ...
     if test:
         out_batched = [
             i
@@ -45,6 +43,7 @@ def g():
 
 
 async def func():
+    await ...
     if test:
         out_batched = [
             i

tests/data/cases/python38.py

@@ -1,6 +1,3 @@
-# flags: --minimum-version=3.8
-
-
 def starred_return():
     my_list = ["value2", "value3"]
     return "value1", *my_list

tests/data/cases/python39.py

@@ -1,5 +1,3 @@
-# flags: --minimum-version=3.9
-
 @relaxed_decorator[0]
 def f():
     ...

tests/data/cases/remove_lone_list_item_parens.py

@@ -0,0 +1,157 @@
+items = [(123)]
+items = [(True)]
+items = [(((((True)))))]
+items = [(((((True,)))))]
+items = [((((()))))]
+items = [(x for x in [1])]
+items = {(123)}
+items = {(True)}
+items = {(((((True)))))}
+
+# Requires `hug_parens_with_braces_and_square_brackets` unstable style to remove parentheses
+# around multiline values
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2"}
+        if some_var == ""
+        else {"key": "val"}
+    )
+]
+
+# Comments should not cause crashes
+items = [
+    (  # comment
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )  # comment
+]
+
+items = [  # comment
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]  # comment
+
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}  # comment
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+
+items = [  # comment
+    (  # comment
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )  # comment
+]  # comment
+
+
+# output
+items = [123]
+items = [True]
+items = [True]
+items = [(True,)]
+items = [()]
+items = [(x for x in [1])]
+items = {123}
+items = {True}
+items = {True}
+
+# Requires `hug_parens_with_braces_and_square_brackets` unstable style to remove parentheses
+# around multiline values
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [{"key1": "val1", "key2": "val2"} if some_var == "" else {"key": "val"}]
+
+# Comments should not cause crashes
+items = [
+    (  # comment
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )  # comment
+]
+
+items = [  # comment
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]  # comment
+
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}  # comment
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+
+items = [  # comment
+    (  # comment
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )
+]
+items = [
+    (
+        {"key1": "val1", "key2": "val2", "key3": "val3"}
+        if some_var == "long strings"
+        else {"key": "val"}
+    )  # comment
+]  # comment

tests/data/cases/remove_redundant_parens_in_case_guard.py

@@ -1,4 +1,4 @@
-# flags: --minimum-version=3.10 --preview --line-length=79
+# flags: --minimum-version=3.10 --line-length=79
 
 match 1:
     case _ if (True):

tests/data/cases/remove_with_brackets.py

@@ -1,4 +1,3 @@
-# flags: --minimum-version=3.9
 with (open("bla.txt")):
     pass
 
@@ -54,6 +53,19 @@
 with ((((CtxManager1()))) as example1, (((CtxManager2()))) as example2):
     ...
 
+# regression tests for #3678
+with (a, *b):
+    pass
+
+with (a, (b, *c)):
+    pass
+
+with (a for b in c):
+    pass
+
+with (a, (b for c in d)):
+    pass
+
 # output
 with open("bla.txt"):
     pass
@@ -118,3 +130,16 @@
 
 with CtxManager1() as example1, CtxManager2() as example2:
     ...
+
+# regression tests for #3678
+with (a, *b):
+    pass
+
+with a, (b, *c):
+    pass
+
+with (a for b in c):
+    pass
+
+with a, (b for c in d):
+    pass

tests/data/cases/skip_magic_trailing_comma_generic_wrap.py

@@ -0,0 +1,163 @@
+# flags: --minimum-version=3.12 --skip-magic-trailing-comma
+def plain[T, B](a: T, b: T) -> T:
+    return a
+
+def arg_magic[T, B](a: T, b: T,) -> T:
+    return a
+
+def type_param_magic[T, B,](a: T, b: T) -> T:
+    return a
+
+def both_magic[T, B,](a: T, b: T,) -> T:
+    return a
+
+
+def plain_multiline[
+    T,
+    B
+](
+    a: T,
+    b: T
+) -> T:
+    return a
+
+def arg_magic_multiline[
+    T,
+    B
+](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+def type_param_magic_multiline[
+    T,
+    B,
+](
+    a: T,
+    b: T
+) -> T:
+    return a
+
+def both_magic_multiline[
+    T,
+    B,
+](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+
+def plain_mixed1[
+    T,
+    B
+](a: T, b: T) -> T:
+    return a
+
+def plain_mixed2[T, B](
+    a: T,
+    b: T
+) -> T:
+    return a
+
+def arg_magic_mixed1[
+    T,
+    B
+](a: T, b: T,) -> T:
+    return a
+
+def arg_magic_mixed2[T, B](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+def type_param_magic_mixed1[
+    T,
+    B,
+](a: T, b: T) -> T:
+    return a
+
+def type_param_magic_mixed2[T, B,](
+    a: T,
+    b: T
+) -> T:
+    return a
+
+def both_magic_mixed1[
+    T,
+    B,
+](a: T, b: T,) -> T:
+    return a
+
+def both_magic_mixed2[T, B,](
+    a: T,
+    b: T,
+) -> T:
+    return a
+
+
+# output
+def plain[T, B](a: T, b: T) -> T:
+    return a
+
+
+def arg_magic[T, B](a: T, b: T) -> T:
+    return a
+
+
+def type_param_magic[T, B](a: T, b: T) -> T:
+    return a
+
+
+def both_magic[T, B](a: T, b: T) -> T:
+    return a
+
+
+def plain_multiline[T, B](a: T, b: T) -> T:
+    return a
+
+
+def arg_magic_multiline[T, B](a: T, b: T) -> T:
+    return a
+
+
+def type_param_magic_multiline[T, B](a: T, b: T) -> T:
+    return a
+
+
+def both_magic_multiline[T, B](a: T, b: T) -> T:
+    return a
+
+
+def plain_mixed1[T, B](a: T, b: T) -> T:
+    return a
+
+
+def plain_mixed2[T, B](a: T, b: T) -> T:
+    return a
+
+
+def arg_magic_mixed1[T, B](a: T, b: T) -> T:
+    return a
+
+
+def arg_magic_mixed2[T, B](a: T, b: T) -> T:
+    return a
+
+
+def type_param_magic_mixed1[T, B](a: T, b: T) -> T:
+    return a
+
+
+def type_param_magic_mixed2[T, B](a: T, b: T) -> T:
+    return a
+
+
+def both_magic_mixed1[T, B](a: T, b: T) -> T:
+    return a
+
+
+def both_magic_mixed2[T, B](a: T, b: T) -> T:
+    return a

tests/data/cases/type_param_defaults.py

@@ -20,6 +20,8 @@ def trailing_comma1[T=int,](a: str):
 def trailing_comma2[T=int](a: str,):
     pass
 
+def weird_syntax[T=lambda: 42, **P=lambda: 43, *Ts=lambda: 44](): pass
+
 # output
 
 type A[T = int] = float
@@ -37,25 +39,31 @@ def trailing_comma2[T=int](a: str,):
 ] = something_that_is_long
 
 
-def simple[
-    T = something_that_is_long
-](short1: int, short2: str, short3: bytes) -> float:
+def simple[T = something_that_is_long](
+    short1: int, short2: str, short3: bytes
+) -> float:
     pass
 
 
-def longer[
-    something_that_is_long = something_that_is_long
-](something_that_is_long: something_that_is_long) -> something_that_is_long:
+def longer[something_that_is_long = something_that_is_long](
+    something_that_is_long: something_that_is_long,
+) -> something_that_is_long:
     pass
 
 
 def trailing_comma1[
     T = int,
-](a: str):
+](
+    a: str,
+):
     pass
 
 
-def trailing_comma2[
-    T = int
-](a: str,):
+def trailing_comma2[T = int](
+    a: str,
+):
+    pass
+
+
+def weird_syntax[T = lambda: 42, **P = lambda: 43, *Ts = lambda: 44]():
     pass

tests/data/cases/type_params.py

@@ -13,6 +13,8 @@ def it_gets_worse[WhatIsTheLongestTypeVarNameYouCanThinkOfEnoughToMakeBlackSplit
 
 def magic[Trailing, Comma,](): pass
 
+def weird_syntax[T: lambda: 42, U: a or b](): pass
+
 # output
 
 
@@ -56,3 +58,7 @@ def magic[
     Comma,
 ]():
     pass
+
+
+def weird_syntax[T: lambda: 42, U: a or b]():
+    pass

tests/data/cases/typed_params_trailing_comma.py

@@ -1,4 +1,3 @@
-# flags: --preview
 def long_function_name_goes_here(
     x: Callable[List[int]]
 ) -> Union[List[int], float, str, bytes, Tuple[int]]:

tests/data/cases/walrus_in_dict.py

@@ -1,9 +1,9 @@
 # flags: --preview
-# This is testing an issue that is specific to the preview style
+# This is testing an issue that is specific to the preview style (wrap_long_dict_values_in_parens)
 {
     "is_update": (up := commit.hash in update_hashes)
 }
 
 # output
-# This is testing an issue that is specific to the preview style
+# This is testing an issue that is specific to the preview style (wrap_long_dict_values_in_parens)
 {"is_update": (up := commit.hash in update_hashes)}

tests/data/miscellaneous/debug_visitor.out

@@ -232,8 +232,6 @@ file_input
                         fstring
                           FSTRING_START
  "f'"
-                          FSTRING_MIDDLE
- ''
                           fstring_replacement_field
                             LBRACE
  '{'
@@ -242,8 +240,6 @@ file_input
                             RBRACE
  '}'
                           /fstring_replacement_field
-                          FSTRING_MIDDLE
- ''
                           fstring_replacement_field
                             LBRACE
  '{'
@@ -252,8 +248,6 @@ file_input
                             RBRACE
  '}'
                           /fstring_replacement_field
-                          FSTRING_MIDDLE
- ''
                           FSTRING_END
  "'"
                         /fstring
@@ -399,8 +393,6 @@ file_input
                         fstring
                           FSTRING_START
  "f'"
-                          FSTRING_MIDDLE
- ''
                           fstring_replacement_field
                             LBRACE
  '{'
@@ -419,8 +411,6 @@ file_input
                             RBRACE
  '}'
                           /fstring_replacement_field
-                          FSTRING_MIDDLE
- ''
                           FSTRING_END
  "'"
                         /fstring
@@ -549,8 +539,6 @@ file_input
                         fstring
                           FSTRING_START
  "f'"
-                          FSTRING_MIDDLE
- ''
                           fstring_replacement_field
                             LBRACE
  '{'
@@ -559,8 +547,6 @@ file_input
                             RBRACE
  '}'
                           /fstring_replacement_field
-                          FSTRING_MIDDLE
- ''
                           fstring_replacement_field
                             LBRACE
  '{'
@@ -569,8 +555,6 @@ file_input
                             RBRACE
  '}'
                           /fstring_replacement_field
-                          FSTRING_MIDDLE
- ''
                           FSTRING_END
  "'"
                         /fstring
@@ -660,8 +644,6 @@ file_input
                                 RBRACE
  '}'
                               /fstring_replacement_field
-                              FSTRING_MIDDLE
- ''
                               FSTRING_END
  "'"
                             /fstring
@@ -744,8 +726,6 @@ file_input
                             RBRACE
  '}'
                           /fstring_replacement_field
-                          FSTRING_MIDDLE
- ''
                           FSTRING_END
  "'"
                         /fstring

tests/optional.py

@@ -18,7 +18,7 @@
 import logging
 import re
 from functools import lru_cache
-from typing import TYPE_CHECKING, FrozenSet, List, Set
+from typing import TYPE_CHECKING
 
 import pytest
 
@@ -46,8 +46,8 @@
     from _pytest.nodes import Node
 
 
-ALL_POSSIBLE_OPTIONAL_MARKERS = StashKey[FrozenSet[str]]()
-ENABLED_OPTIONAL_MARKERS = StashKey[FrozenSet[str]]()
+ALL_POSSIBLE_OPTIONAL_MARKERS = StashKey[frozenset[str]]()
+ENABLED_OPTIONAL_MARKERS = StashKey[frozenset[str]]()
 
 
 def pytest_addoption(parser: "Parser") -> None:
@@ -69,7 +69,7 @@ def pytest_configure(config: "Config") -> None:
     """
     ot_ini = config.inicfg.get("optional-tests") or []
     ot_markers = set()
-    ot_run: Set[str] = set()
+    ot_run: set[str] = set()
     if isinstance(ot_ini, str):
         ot_ini = ot_ini.strip().split("\n")
     marker_re = re.compile(r"^\s*(?P<no>no_)?(?P<marker>\w+)(:\s*(?P<description>.*))?")
@@ -103,7 +103,7 @@ def pytest_configure(config: "Config") -> None:
     store[ENABLED_OPTIONAL_MARKERS] = frozenset(ot_run)
 
 
-def pytest_collection_modifyitems(config: "Config", items: "List[Node]") -> None:
+def pytest_collection_modifyitems(config: "Config", items: "list[Node]") -> None:
     store = config._store
     all_possible_optional_markers = store[ALL_POSSIBLE_OPTIONAL_MARKERS]
     enabled_optional_markers = store[ENABLED_OPTIONAL_MARKERS]
@@ -120,7 +120,7 @@ def pytest_collection_modifyitems(config: "Config", items: "List[Node]") -> None
 
 
 @lru_cache
-def skip_mark(tests: FrozenSet[str]) -> "MarkDecorator":
+def skip_mark(tests: frozenset[str]) -> "MarkDecorator":
     names = ", ".join(sorted(tests))
     return pytest.mark.skip(reason=f"Marked with disabled optional tests ({names})")