Ignore the open parentheses when measuring `BestFitsParenthesize` #8940

MichaReiser · 2023-12-01T04:00:43Z

Summary

This PR changes the definition of BestFitParenthesize to only consider whether its content fits when parenthesizing and not whether the whole parenthesized expression fits.

The difference is subtle but relevant when what comes before BestFitParenthesize already exceeds the configured line width:

this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = aaaaaa

The this_is_a... exceeds the configured line width. The existing implementation doesn't parenthesize aaaaa because the opening ( doesn't fit on the line. This is unfortunate, because parenthesizing would make aaaaa fit in the configured line width and is what Black does:

this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = (
    aaaaaa
)

This PR implements Black's behavior by ignoring whether there's sufficient space to place the ( and instead only measures whether its content (aaaaaa) fits when indenting.

Test Plan

The similarity index remains unchanged.

project	similarity index	total files	changed files
cpython	0.75804	1799	1648
django	0.99984	2772	34
home-assistant	0.99955	10596	213
poetry	0.96208	317	35
transformers	0.99967	2657	324
twine	1.00000	33	0
typeshed	0.99980	3669	18
warehouse	0.99976	654	14
zulip	0.99957	1459	36

MichaReiser · 2023-12-01T04:00:54Z

Current dependencies on/for this PR:

main
- PR Refactor the comment handling of a statement's last expression #8920
  - PR prefer_splitting_right_hand_side_of_assignments preview style #8943
    - PR Implement Black's parenthesize-long-type-hints preview style #9102
  - PR Inline trailing comments for type alias similar to assignments #8941
    - PR Ignore the open parentheses when measuring BestFitsParenthesize #8940 👈

This stack of pull requests is managed by Graphite.

MichaReiser · 2023-12-01T04:05:19Z

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__comments6.py.snap

 -        3
 -    )  # type: int
-+    another_really_really_long_element_with_a_unnecessarily_long_name_to_describe_what_it_does_enterprise_style = 3  # type: int
+        3  # type: int


The style here is different because black doesn't inline the type: comment. Changing the comment to e.g. ctype matches Ruff's formatting

MichaReiser · 2023-12-01T04:05:39Z

..._formatter/tests/snapshots/black_compatibility@cases__pep604_union_types_line_breaks.py.snap

@@ -123,14 +123,16 @@ def f(
 -z: Short | Short2 | Short3 | Short4 = 8
 -z: int = 2.3
 -z: int = foo()
-+z: Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong = 7
+z: Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong = (


Requires other preview styles to match black

MichaReiser · 2023-12-01T04:06:15Z

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__preview_cantfit.py.snap

 )
-@@ -35,10 +29,8 @@
+-this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = function(


Requires other preview styles to match Black

MichaReiser · 2023-12-01T04:08:05Z

crates/ruff_python_formatter/tests/snapshots/format@expression__yield.py.snap

@@ -165,7 +165,9 @@ def foo():
        yield (e)  # Too many parentheses
        # comment

-    for ridiculouslylongelementnameeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee in l:
+    for ridiculouslylongelementnameeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee in (


This doesn't match black although black's formatting here is very peculiar

for ridiculouslylongelementnameeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee in (l): pass

It ends parenthesizing l but without splitting the line. IMO, both styles are not ideal but I prefer ours for consistency.

MichaReiser · 2023-12-01T04:09:13Z

crates/ruff_python_formatter/tests/snapshots/format@statement__type_alias.py.snap

+type Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx = (
+    int
+)


This is a divergence from Black. Black doesn't parenthesize the right side. I don't see why and recommend keeping it because I don't see why type aliases should be different from other assignments.

github-actions · 2023-12-01T04:11:19Z

`ruff-ecosystem` results

Formatter (stable)

ℹ️ ecosystem check detected format changes. (+4 -2 lines in 1 file in 41 projects)

latchbio/latch (+4 -2 lines across 1 file)

latch/idl/core/interface.py~L58

     var: Variable
     """+required Variable. Defines the type of the variable backing this parameter."""
 
-    behavior: "Optional[typing.Union[ParameterBehaviorDefault, ParameterBehaviorRequired]]" = None
+    behavior: "Optional[typing.Union[ParameterBehaviorDefault, ParameterBehaviorRequired]]" = (
+        None
+    )
 
     def to_idl(self) -> pb.Parameter:
         return merged_pb(pb.Parameter(var=self.var.to_idl()), self.behavior)

Formatter (preview)

ℹ️ ecosystem check detected format changes. (+4 -2 lines in 1 file in 41 projects)

latchbio/latch (+4 -2 lines across 1 file)

ruff format --preview

latch/idl/core/interface.py~L58

     var: Variable
     """+required Variable. Defines the type of the variable backing this parameter."""
 
-    behavior: "Optional[typing.Union[ParameterBehaviorDefault, ParameterBehaviorRequired]]" = None
+    behavior: "Optional[typing.Union[ParameterBehaviorDefault, ParameterBehaviorRequired]]" = (
+        None
+    )
 
     def to_idl(self) -> pb.Parameter:
         return merged_pb(pb.Parameter(var=self.var.to_idl()), self.behavior)

MichaReiser · 2023-12-01T04:56:40Z

Hmm, obviously, it is more complicated than this 🤯

Black does not parenthesize the right side here (for reasons?)

this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = (
    function(arg1, arg2, arg3)
)

Although function is clearly over the configured width and parenthesizing helps make it fit. Instead, black picks

this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = function(
    arg1, arg2, arg3
)

Ultimately, the vertical spacing is about the same, although Black's layout requires considerably more vertical spacing. However, it avoids one pair of parentheses, which is something Black generally optimizes for.

Which makes me wonder what their rule is.

MichaReiser · 2023-12-01T06:54:03Z

Okay this is interesting. Black does the exact opposite if the right hand side is a function

this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_i = (
    function([1, 2, 3], arg1, [1, 2, 3], arg2, [1, 2, 3], arg3)
)

this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = function(
    [1, 2, 3], arg1, [1, 2, 3], arg2, [1, 2, 3], arg3
)

The ( fits for the first example, which is why Black parenthesizes the entire function (at least it seems). The ( doesn't fit for the second example, which is why Black avoids parenthesizing the function.

I compared the similarity index for Poetry using either layout, and it remained unchanged. This feels edge-casey enough that I feel it isn't worth spending too much time on. However, I'm undecided which version I prefer:

Always parenthesizing if it makes the content fit gets the result closer to the ultimate goal of fitting code into the configured line width. It's also closer to how our formatter works overall, which generally eagerly parenthesizes expressions. For example, this gets always parenthesized this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = a + b

Avoiding the parentheses if even the ( doesn't fit results in fewer parentheses overall, which is a secondary goal. It can be slightly more readable if you e.g. have

this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = function(
    [1, 2, 3],
    arg1,
    [1, 2, 3],
    arg2,
    [1, 2, 3],
    arg3,
    dddddddddddddddddddd,
    eeeeeeeeeeeeee,
)
# instead of
this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = (
    function(
        [1, 2, 3],
        arg1,
        [1, 2, 3],
        arg2,
        [1, 2, 3],
        arg3,
        dddddddddddddddddddd,
        eeeeeeeeeeeeee,
    )
)

Would love to hear some more opinions on this

MichaReiser added the formatter Related to the formatter label Dec 1, 2023

MichaReiser commented Dec 1, 2023

View reviewed changes

MichaReiser requested a review from charliermarsh December 1, 2023 04:25

MichaReiser marked this pull request as ready for review December 1, 2023 04:26

MichaReiser added 2 commits December 1, 2023 12:31

Refactor the comment handling of a statement's last expression

1de4fcd

Inline comments for type alias similar to assignment

7d948b2

MichaReiser force-pushed the best-fit-content-only branch from cf3fa1c to d50fa88 Compare December 1, 2023 04:41

MichaReiser changed the base branch from main to align-type-alias-with-assignment-formatting December 1, 2023 04:41

This was referenced Dec 1, 2023

Refactor the comment handling of a statement's last expression #8920

Merged

Inline trailing comments for type alias similar to assignments #8941

Merged

Ignore the open parentheses when measuring BestFitsParenthesize

d013b71

MichaReiser force-pushed the best-fit-content-only branch from d50fa88 to d013b71 Compare December 1, 2023 05:09

MichaReiser mentioned this pull request Dec 1, 2023

prefer_splitting_right_hand_side_of_assignments preview style #8943

Merged

charliermarsh approved these changes Dec 1, 2023

View reviewed changes

MichaReiser force-pushed the align-type-alias-with-assignment-formatting branch from 7d948b2 to 8fbb3c8 Compare December 4, 2023 05:15

Base automatically changed from align-type-alias-with-assignment-formatting to main December 4, 2023 05:27

MichaReiser mentioned this pull request Dec 12, 2023

Implement Black's parenthesize-long-type-hints preview style #9102

Closed

MichaReiser closed this Dec 14, 2023

MichaReiser deleted the best-fit-content-only branch January 16, 2024 10:03

MichaReiser restored the best-fit-content-only branch June 10, 2024 08:17

This was referenced Jun 10, 2024

formatter deviation: line break not occurring on assignments where LHS goes over line-length #11820

Open

Formatter: deviation from black: dict key split to multiline #11857

Open

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Ignore the open parentheses when measuring `BestFitsParenthesize` #8940

Ignore the open parentheses when measuring `BestFitsParenthesize` #8940

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Ignore the open parentheses when measuring BestFitsParenthesize #8940

Ignore the open parentheses when measuring BestFitsParenthesize #8940

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ruff-ecosystem results

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Ignore the open parentheses when measuring `BestFitsParenthesize` #8940

Ignore the open parentheses when measuring `BestFitsParenthesize` #8940

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