Ignore the open parentheses when measuring BestFitsParenthesize

crates/ruff_formatter/src/builders.rs

@@ -1451,11 +1451,12 @@ impl<Context> std::fmt::Debug for Group<'_, Context> {
     }
 }
 
-/// Content that may get parenthesized if it exceeds the configured line width but only if the parenthesized
-/// layout doesn't exceed the line width too, in which case it falls back to the flat layout.
+/// Content that may get parenthesized if it exceeds the configured line width but only if the parenthesized content
+/// doesn't exceed the line width too, in which case it falls back to the flat layout.
 ///
-/// This IR is identical to the following [`best_fitting`] layout but is implemented as custom IR for
-/// best performance.
+/// This IR is almost identical to the following [`best_fitting`] layout but is implemented as custom IR for
+/// best performance. It differs in that the open parentheses is ignored when testing if the content fits because
+/// the goal is to only parenthesize the content if parenthesizing makes the content fit.
 ///
 /// ```rust
 /// # use ruff_formatter::prelude::*;

crates/ruff_formatter/src/printer/mod.rs

@@ -203,7 +203,9 @@ impl<'a> Printer<'a> {
                         args.with_measure_mode(MeasureMode::AllLines),
                     );
 
-                    queue.extend_back(&[OPEN_PAREN, INDENT, HARD_LINE_BREAK]);
+                    // Don't measure the opening parentheses. Only concerned whether parenthesizing
+                    // makes the content fit.
+                    queue.extend_back(&[INDENT, HARD_LINE_BREAK]);
                     let fits_expanded = self.fits(queue, stack)?;
                     queue.pop_slice();
                     stack.pop(TagKind::BestFitParenthesize)?;

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

@@ -130,18 +130,18 @@ aaaaaaaaaaaaa, bbbbbbbbb = map(list, map(itertools.chain.from_iterable, zip(*ite
 ```diff
 --- Black
 +++ Ruff
-@@ -49,9 +49,7 @@
-     element = 0  # type: int
+@@ -50,8 +50,8 @@
      another_element = 1  # type: float
      another_element_with_long_name = 2  # type: int
--    another_really_really_long_element_with_a_unnecessarily_long_name_to_describe_what_it_does_enterprise_style = (
+     another_really_really_long_element_with_a_unnecessarily_long_name_to_describe_what_it_does_enterprise_style = (
 -        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
++    )
      an_element_with_a_long_value = calls() or more_calls() and more()  # type: bool
  
      tup = (
-@@ -100,7 +98,13 @@
+@@ -100,7 +100,13 @@
      )
  
      c = call(
@@ -156,7 +156,7 @@ aaaaaaaaaaaaa, bbbbbbbbb = map(list, map(itertools.chain.from_iterable, zip(*ite
      )
  
  
-@@ -108,11 +112,18 @@
+@@ -108,11 +114,18 @@
      "xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
  )
  
@@ -233,7 +233,9 @@ def f(
     element = 0  # type: int
     another_element = 1  # type: float
     another_element_with_long_name = 2  # type: int
-    another_really_really_long_element_with_a_unnecessarily_long_name_to_describe_what_it_does_enterprise_style = 3  # type: int
+    another_really_really_long_element_with_a_unnecessarily_long_name_to_describe_what_it_does_enterprise_style = (
+        3  # type: int
+    )
     an_element_with_a_long_value = calls() or more_calls() and more()  # type: bool
 
     tup = (

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__pep604_union_types_line_breaks.py.snap

@@ -95,7 +95,7 @@ def f(
 ```diff
 --- Black
 +++ Ruff
-@@ -7,26 +7,16 @@
+@@ -7,26 +7,18 @@
  )
  
  # "AnnAssign"s now also work
@@ -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 = (
++    7
++)
 +z: (Short | Short2 | Short3 | Short4) = 8
 +z: (int) = 2.3
 +z: (int) = foo()
  
  # In case I go for not enforcing parantheses, this might get improved at the same time
  x = (
-@@ -63,7 +53,7 @@
+@@ -63,7 +55,7 @@
  
  
  # remove unnecessary paren
@@ -139,7 +141,7 @@ def f(
  
  
  # this is a syntax error in the type annotation according to mypy, but it's not invalid *python* code, so make sure we don't mess with it and make it so.
-@@ -72,12 +62,10 @@
+@@ -72,12 +64,10 @@
  
  def foo(
      i: int,
@@ -156,7 +158,7 @@ def f(
      *,
      s: str,
  ) -> None:
-@@ -88,7 +76,7 @@
+@@ -88,7 +78,7 @@
  async def foo(
      q: str | None = Query(
          None, title="Some long title", description="Some long description"
@@ -185,7 +187,9 @@ z: (int)
 z: (int)
 
 
-z: Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong = 7
+z: Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong | Loooooooooooooooooooooooong = (
+    7
+)
 z: (Short | Short2 | Short3 | Short4) = 8
 z: (int) = 2.3
 z: (int) = foo()

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

@@ -51,29 +51,23 @@ del concatenated_strings, string_variable_name, normal_function_name, normal_nam
 ```diff
 --- Black
 +++ Ruff
-@@ -1,18 +1,12 @@
- # 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
--)
-+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
- this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = [
-     1,
-     2,
-     3,
- ]
--this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = (
--    function()
--)
-+this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = function()
- this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = function(
-     arg1, arg2, arg3
+@@ -13,11 +13,11 @@
+ this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = (
+     function()
  )
-@@ -35,10 +29,8 @@
+-this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = function(
+-    arg1, arg2, arg3
++this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = (
++    function(arg1, arg2, 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
++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)
+ )
+ # long function name
+ normal_name = (
+@@ -35,10 +35,8 @@
  )
  # long arguments
  normal_name = normal_function_name(
@@ -92,19 +86,25 @@ del concatenated_strings, string_variable_name, normal_function_name, normal_nam
 
 ```python
 # 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
+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
+)
 this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = [
     1,
     2,
     3,
 ]
-this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = function()
-this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = function(
-    arg1, arg2, arg3
+this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = (
+    function()
 )
-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
+this_is_a_ridiculously_long_name_and_nobody_in_their_right_mind_would_use_one_like_it = (
+    function(arg1, arg2, 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)
 )
 # long function name
 normal_name = (

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

@@ -290,7 +290,9 @@ def f(*args, **kwargs):
     pass
 
 
-this_is_a_very_long_argument_asökdhflakjslaslhfdlaffahflahsöfdhasägporejfäalkdsjäfalisjäfdlkasjd = 1
+this_is_a_very_long_argument_asökdhflakjslaslhfdlaffahflahsöfdhasägporejfäalkdsjäfalisjäfdlkasjd = (
+    1
+)
 session = MagicMock()
 models = MagicMock()
 

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 (
+        l
+    ):
         yield ridiculouslylongelementnameeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee
 
     for x in l:  # comment

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

@@ -115,7 +115,9 @@ type X[T: int, *Ts, **P] = (T, Ts, P)
 type X[T: (int, str), *Ts, **P] = (T, Ts, P)
 
 # long name
-type Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx = int
+type Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx = (
+    int
+)
 type Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx[
     A
 ] = int
@@ -126,7 +128,9 @@ type Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
     Aaaaaaaaaaaaaaaaaaaaaaaaaaaa,
     Bbbbbbbbbbbbb,
 ] = int
-type Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx = Tttttttttttttttttttttttttttttttttttttttttttttttttttttttt
+type Xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx = (
+    Tttttttttttttttttttttttttttttttttttttttttttttttttttttttt
+)
 
 # long value
 type X = Ttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttttt