Remove whitespaces of whitespace-only files (#3348)
Currently, empty and whitespace-only (with or without newlines) are not modified. In some discussions (issues and pull requests) consensus was to reformat whitespace-only files to empty or single-character files, preserving line endings when possible. With that said, this commit introduces the following behaviors: * Empty files are left as is * Whitespace-only files (no newline) reformat into empty files * Whitespace-only files (1 or more newlines) reformat into a single newline character To implement these changes, we moved the initial check at `format_file_contents` that raises `NothingChanged` if the source (with no whitespaces) is an empty string. In the case of *.ipynb files, `format_ipynb_string` checks a similar condition and removed whitespaces. In the case of Python files, `format_str_once` includes a check on the output that returns the correct newline character if possible or an empty string otherwise. Signed-off-by: Antonio Ossa Guerra <aaossa@uc.cl>
This commit is contained in:
Antonio Ossa-Guerra
GitHub
parent
c23a5c15aa
commit
d97b7898b3
@ -15,6 +15,8 @@
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<!-- Changes that affect Black's preview style -->
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- Enforce empty lines before classes and functions with sticky leading comments (#3302)
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- Reformat empty and whitespace-only files as either an empty file (if no newline is
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present) or as a single newline character (if a newline is present) (#3348)
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- Implicitly concatenated strings used as function args are now wrapped inside
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parentheses (#3307)
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- Correctly handle trailing commas that are inside a line's leading non-nested parens
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@ -917,7 +917,7 @@ def format_file_contents(src_contents: str, *, fast: bool, mode: Mode) -> FileCo
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valid by calling :func:`assert_equivalent` and :func:`assert_stable` on it.
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`mode` is passed to :func:`format_str`.
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"""
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if not src_contents.strip():
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if not mode.preview and not src_contents.strip():
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raise NothingChanged
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if mode.is_ipynb:
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@ -1014,6 +1014,9 @@ def format_ipynb_string(src_contents: str, *, fast: bool, mode: Mode) -> FileCon
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Operate cell-by-cell, only on code cells, only for Python notebooks.
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If the ``.ipynb`` originally had a trailing newline, it'll be preserved.
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"""
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if mode.preview and not src_contents:
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raise NothingChanged
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trailing_newline = src_contents[-1] == "\n"
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modified = False
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nb = json.loads(src_contents)
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@ -1106,6 +1109,13 @@ def _format_str_once(src_contents: str, *, mode: Mode) -> str:
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dst_contents = []
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for block in dst_blocks:
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dst_contents.extend(block.all_lines())
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if mode.preview and not dst_contents:
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# Use decode_bytes to retrieve the correct source newline (CRLF or LF),
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# and check if normalized_content has more than one line
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normalized_content, _, newline = decode_bytes(src_contents.encode("utf-8"))
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if "\n" in normalized_content:
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return newline
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return ""
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return "".join(dst_contents)
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6
tests/data/preview/whitespace.py
Normal file
6
tests/data/preview/whitespace.py
Normal file
@ -0,0 +1,6 @@
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# output
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@ -25,6 +25,7 @@
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List,
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Optional,
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Sequence,
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Type,
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TypeVar,
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Union,
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)
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@ -153,6 +154,34 @@ def test_empty_ff(self) -> None:
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os.unlink(tmp_file)
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self.assertFormatEqual(expected, actual)
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@patch("black.dump_to_file", dump_to_stderr)
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def test_one_empty_line(self) -> None:
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mode = black.Mode(preview=True)
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for nl in ["\n", "\r\n"]:
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source = expected = nl
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assert_format(source, expected, mode=mode)
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def test_one_empty_line_ff(self) -> None:
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mode = black.Mode(preview=True)
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for nl in ["\n", "\r\n"]:
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expected = nl
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tmp_file = Path(black.dump_to_file(nl))
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if system() == "Windows":
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# Writing files in text mode automatically uses the system newline,
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# but in this case we don't want this for testing reasons. See:
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# https://github.com/psf/black/pull/3348
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with open(tmp_file, "wb") as f:
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f.write(nl.encode("utf-8"))
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try:
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self.assertFalse(
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ff(tmp_file, mode=mode, write_back=black.WriteBack.YES)
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)
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with open(tmp_file, "rb") as f:
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actual = f.read().decode("utf8")
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finally:
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os.unlink(tmp_file)
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self.assertFormatEqual(expected, actual)
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def test_experimental_string_processing_warns(self) -> None:
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self.assertWarns(
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black.mode.Deprecated, black.Mode, experimental_string_processing=True
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@ -971,8 +1000,8 @@ def err(msg: str, **kwargs: Any) -> None:
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)
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def test_format_file_contents(self) -> None:
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empty = ""
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mode = DEFAULT_MODE
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empty = ""
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with self.assertRaises(black.NothingChanged):
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black.format_file_contents(empty, mode=mode, fast=False)
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just_nl = "\n"
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@ -990,6 +1019,17 @@ def test_format_file_contents(self) -> None:
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black.format_file_contents(invalid, mode=mode, fast=False)
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self.assertEqual(str(e.exception), "Cannot parse: 1:7: return if you can")
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mode = black.Mode(preview=True)
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just_crlf = "\r\n"
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with self.assertRaises(black.NothingChanged):
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black.format_file_contents(just_crlf, mode=mode, fast=False)
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just_whitespace_nl = "\n\t\n \n\t \n \t\n\n"
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actual = black.format_file_contents(just_whitespace_nl, mode=mode, fast=False)
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self.assertEqual("\n", actual)
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just_whitespace_crlf = "\r\n\t\r\n \r\n\t \r\n \t\r\n\r\n"
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actual = black.format_file_contents(just_whitespace_crlf, mode=mode, fast=False)
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self.assertEqual("\r\n", actual)
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def test_endmarker(self) -> None:
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n = black.lib2to3_parse("\n")
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self.assertEqual(n.type, black.syms.file_input)
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@ -1281,8 +1321,51 @@ def test_reformat_one_with_stdin_and_existing_path(self) -> None:
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report.done.assert_called_with(expected, black.Changed.YES)
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def test_reformat_one_with_stdin_empty(self) -> None:
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cases = [
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("", ""),
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("\n", "\n"),
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("\r\n", "\r\n"),
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(" \t", ""),
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(" \t\n\t ", "\n"),
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(" \t\r\n\t ", "\r\n"),
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]
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def _new_wrapper(
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output: io.StringIO, io_TextIOWrapper: Type[io.TextIOWrapper]
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) -> Callable[[Any, Any], io.TextIOWrapper]:
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def get_output(*args: Any, **kwargs: Any) -> io.TextIOWrapper:
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if args == (sys.stdout.buffer,):
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# It's `format_stdin_to_stdout()` calling `io.TextIOWrapper()`,
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# return our mock object.
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return output
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# It's something else (i.e. `decode_bytes()`) calling
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# `io.TextIOWrapper()`, pass through to the original implementation.
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# See discussion in https://github.com/psf/black/pull/2489
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return io_TextIOWrapper(*args, **kwargs)
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return get_output
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mode = black.Mode(preview=True)
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for content, expected in cases:
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output = io.StringIO()
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io_TextIOWrapper = io.TextIOWrapper
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with patch("io.TextIOWrapper", _new_wrapper(output, io_TextIOWrapper)):
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try:
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black.format_stdin_to_stdout(
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fast=True,
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content=content,
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write_back=black.WriteBack.YES,
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mode=mode,
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)
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except io.UnsupportedOperation:
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pass # StringIO does not support detach
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assert output.getvalue() == expected
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# An empty string is the only test case for `preview=False`
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output = io.StringIO()
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with patch("io.TextIOWrapper", lambda *args, **kwargs: output):
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io_TextIOWrapper = io.TextIOWrapper
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with patch("io.TextIOWrapper", _new_wrapper(output, io_TextIOWrapper)):
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try:
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black.format_stdin_to_stdout(
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fast=True,
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