* Blacken .py files in blib2to3
This is in preparation for adding type annotations to blib2to3 in
order to compiling it with mypyc (#1009, which I can rebase on top of
this).
To enforce that it stays blackened, I just cargo-culted the existing
test code used for validating formatting. It feels pretty clunky now,
though, so I can abstract the common logic out into a helper if that
seems better. (But error messages might be less clear then?)
* Tidy up the tests
It turns out we also need to handle invisible *left* parens added at
the *start* of a line. Refactor `contains_unsplittable_type_ignore` to
handle this more cleanly.
* add test for special unicode symbol which usual re can not process correctly
add regex lib which supports unicode 12.1.0 standard
replace re usage in project in favor to regex
* #455 fix dependency
In #1040 I had convinced myself that the type ignore logic didn't
need anything like the ignored_ids from the type comment logic, but I
was wrong, and we do.
We hit these cases in practice a bunch.
The code introduced in #1027 to detect whether a type comment appeared
after a regular comment in a Line would spuriously misfire when a leaf
was in the comments dict but had an empty list of comments. This can
occur as an artifact of how comments on trailing commas are handled,
it seems.
(This was discovered trying to test black out on mypy.)
mypy 0.730 fixed a bug involving nonexistent attributes accessed on
modules, which caused an error since COLONEQUAL never got added to
token.pyi. Add it.
Type comments only apply if they are the first comment on the line,
which means that allowing them to be pushed behind a regular comment
when joining lines is a semantic change (and, indeed, one that black
catches and fails on).
* Parse `:=` properly
* never unwrap parenthesis around `:=`
* When checking for AST-equivalence, use `ast` instead of `typed-ast` when running on python >=3.8
* Assume code that uses `:=` is at least 3.8
W503 and W504 are mutually exclusive, to do with splitting binary operators across lines. Black reformats code according to W504, putting the operator on the start of the newline, therefore W503 needs to be ignored in the suggested Flake8 config to use with Black.
