Don't expand groups for trailing end-of-line comments

crates/ruff_python_formatter/src/comments/format.rs

@@ -161,10 +161,11 @@ impl Format<PyFormatContext<'_>> for FormatTrailingComments<'_> {
             } else {
                 write!(
                     f,
-                    [
-                        line_suffix(&format_args![space(), space(), format_comment(trailing)]),
-                        expand_parent()
-                    ]
+                    [line_suffix(&format_args![
+                        space(),
+                        space(),
+                        format_comment(trailing)
+                    ])]
                 )?;
             }
 
@@ -210,13 +211,17 @@ impl Format<PyFormatContext<'_>> for FormatDanglingComments<'_> {
                 write!(f, [space(), space()])?;
             }
 
-            write!(
-                f,
-                [
-                    format_comment(comment),
-                    empty_lines(lines_after(comment.slice().end(), f.context().source()))
-                ]
-            )?;
+            if comment.line_position.is_end_of_line() {
+                write!(f, [format_comment(comment)])?;
+            } else {
+                write!(
+                    f,
+                    [
+                        format_comment(comment),
+                        empty_lines(lines_after(comment.slice().end(), f.context().source()))
+                    ]
+                )?;
+            }
 
             comment.mark_formatted();
 

crates/ruff_python_formatter/tests/snapshots/black_compatibility@py_310__pattern_matching_style.py.snap

@@ -65,7 +65,7 @@ match match(
 ```diff
 --- Black
 +++ Ruff
-@@ -1,35 +1,34 @@
+@@ -1,16 +1,11 @@
  match something:
 -    case b():
 +    case NOT_YET_IMPLEMENTED_Pattern:
@@ -85,29 +85,9 @@ match match(
 +    case NOT_YET_IMPLEMENTED_Pattern:
          pass
  
--match(arg)  # comment
-+match(
-+    arg  # comment
-+)
- 
- match()
- 
- match()
- 
--case(arg)  # comment
-+case(
-+    arg  # comment
-+)
- 
- case()
- 
- case()
- 
- 
--re.match(something)  # fast
-+re.match(
-+    something  # fast
-+)
+ match(arg)  # comment
+@@ -29,7 +24,5 @@
+ re.match(something)  # fast
  re.match()
  match match():
 -    case case(
@@ -130,26 +110,20 @@ match something:
     case NOT_YET_IMPLEMENTED_Pattern:
         pass
 
-match(
-    arg  # comment
-)
+match(arg)  # comment
 
 match()
 
 match()
 
-case(
-    arg  # comment
-)
+case(arg)  # comment
 
 case()
 
 case()
 
 
-re.match(
-    something  # fast
-)
+re.match(something)  # fast
 re.match()
 match match():
     case NOT_YET_IMPLEMENTED_Pattern:

crates/ruff_python_formatter/tests/snapshots/black_compatibility@simple_cases__comments2.py.snap

@@ -191,21 +191,7 @@ instruction()#comment with bad spacing
  )
  
  # Please keep __all__ alphabetized within each category.
-@@ -60,8 +60,12 @@
- # Comment before function.
- def inline_comments_in_brackets_ruin_everything():
-     if typedargslist:
--        parameters.children = [children[0], body, children[-1]]  # (1  # )1
-         parameters.children = [
-+            children[0],  # (1
-+            body,
-+            children[-1],  # )1
-+        ]
-+        parameters.children = [
-             children[0],
-             body,
-             children[-1],  # type: ignore
-@@ -72,7 +76,11 @@
+@@ -72,7 +72,11 @@
              body,
              parameters.children[-1],  # )2
          ]
@@ -218,41 +204,17 @@ instruction()#comment with bad spacing
      if (
          self._proc is not None
          # has the child process finished?
-@@ -115,7 +123,9 @@
+@@ -114,9 +118,7 @@
+         # yup
          arg3=True,
      )
-     lcomp = [
+-    lcomp = [
 -        element for element in collection if element is not None  # yup  # yup  # right
-+        element  # yup
-+        for element in collection  # yup
-+        if element is not None  # right
-     ]
+-    ]
++    lcomp = [element for element in collection if element is not None]  # yup  # yup  # right
      lcomp2 = [
          # hello
-@@ -143,7 +153,10 @@
-     # let's return
-     return Node(
-         syms.simple_stmt,
--        [Node(statement, result), Leaf(token.NEWLINE, "\n")],  # FIXME: \r\n?
-+        [
-+            Node(statement, result),
-+            Leaf(token.NEWLINE, "\n"),  # FIXME: \r\n?
-+        ],
-     )
- 
- 
-@@ -158,7 +171,10 @@
- 
- class Test:
-     def _init_host(self, parsed) -> None:
--        if parsed.hostname is None or not parsed.hostname.strip():  # type: ignore
-+        if (
-+            parsed.hostname is None  # type: ignore
-+            or not parsed.hostname.strip()
-+        ):
-             pass
- 
- 
+         element
 ```
 
 ## Ruff Output
@@ -320,11 +282,7 @@ else:
 # Comment before function.
 def inline_comments_in_brackets_ruin_everything():
     if typedargslist:
-        parameters.children = [
-            children[0],  # (1
-            body,
-            children[-1],  # )1
-        ]
+        parameters.children = [children[0], body, children[-1]]  # (1  # )1
         parameters.children = [
             children[0],
             body,
@@ -382,11 +340,7 @@ short
         # yup
         arg3=True,
     )
-    lcomp = [
-        element  # yup
-        for element in collection  # yup
-        if element is not None  # right
-    ]
+    lcomp = [element for element in collection if element is not None]  # yup  # yup  # right
     lcomp2 = [
         # hello
         element
@@ -413,10 +367,7 @@ short
     # let's return
     return Node(
         syms.simple_stmt,
-        [
-            Node(statement, result),
-            Leaf(token.NEWLINE, "\n"),  # FIXME: \r\n?
-        ],
+        [Node(statement, result), Leaf(token.NEWLINE, "\n")],  # FIXME: \r\n?
     )
 
 
@@ -431,10 +382,7 @@ CONFIG_FILES = (
 
 class Test:
     def _init_host(self, parsed) -> None:
-        if (
-            parsed.hostname is None  # type: ignore
-            or not parsed.hostname.strip()
-        ):
+        if parsed.hostname is None or not parsed.hostname.strip():  # type: ignore
             pass
 
 

crates/ruff_python_formatter/tests/snapshots/black_compatibility@simple_cases__fmtskip5.py.snap

@@ -21,26 +21,24 @@ else:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,7 +1,7 @@
+@@ -1,9 +1,5 @@
  a, b, c = 3, 4, 5
- if (
-     a == 3
+-if (
+-    a == 3
 -    and b    != 9  # fmt: skip
-+    and b != 9  # fmt: skip
-     and c is not None
- ):
+-    and c is not None
+-):
++if a == 3 and b != 9 and c is not None:  # fmt: skip
      print("I'm good!")
+ else:
+     print("I'm bad")
 ```
 
 ## Ruff Output
 
 ```py
 a, b, c = 3, 4, 5
-if (
-    a == 3
-    and b != 9  # fmt: skip
-    and c is not None
-):
+if a == 3 and b != 9 and c is not None:  # fmt: skip
     print("I'm good!")
 else:
     print("I'm bad")

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

@@ -100,20 +100,7 @@ def foo() -> tuple[int, int, int,]:
 ```diff
 --- Black
 +++ Ruff
-@@ -26,7 +26,11 @@
-     return 2 * a
- 
- 
--def double(a: int) -> int:  # Hello
-+def double(
-+    a: int
-+) -> (
-+    int  # Hello
-+):
-     return 2 * a
- 
- 
-@@ -54,7 +58,9 @@
+@@ -54,7 +54,9 @@
      a: int,
      b: int,
      c: int,
@@ -157,11 +144,7 @@ def double(a: int) -> int:  # Hello
     return 2 * a
 
 
-def double(
-    a: int
-) -> (
-    int  # Hello
-):
+def double(a: int) -> int:  # Hello
     return 2 * a
 
 

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

@@ -255,11 +255,7 @@ c1 = (
 # Fits, either style
 d11 = x.e().e().e()  #
 d12 = x.e().e().e()  #
-d13 = (
-    x.e()  #
-    .e()
-    .e()
-)
+d13 = x.e().e().e()  #
 
 # Doesn't fit, default
 d2 = x.e().esadjkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkfsdddd()  #

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

@@ -506,12 +506,8 @@ x = (
     - (  #
     )
 )
-x = (
-    () - ()  #
-)
-x = (
-    () - ()  #
-)
+x = () - ()  #
+x = () - ()  #
 ```
 
 

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

@@ -195,11 +195,7 @@ result = (
 # TODO(konstin): Black has this special case for comment placement where everything stays in one line
 f("aaaaaaaa", "aaaaaaaa", "aaaaaaaa", "aaaaaaaa", "aaaaaaaa", "aaaaaaaa", "aaaaaaaa")
 
-f(
-    session,
-    b=1,
-    **dict(),  # oddly placed end-of-line comment
-)
+f(session, b=1, **dict())  # oddly placed end-of-line comment
 f(
     session,
     b=1,

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

@@ -138,10 +138,7 @@ a not in b
     == b
 )
 
-(
-    a  # comment
-    == b
-)
+(a == b)  # comment
 
 a < b > c == d
 

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

@@ -78,14 +78,9 @@ x={  # dangling end of line comment
 
 {**d}
 
-{
-    **a,  #  leading
-    **b,  # middle  # trailing
-}
+{**a, **b}  #  leading  # middle  # trailing
 
-{
-    **b  # middle with single item
-}
+{**b}  # middle with single item
 
 {
     # before

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

@@ -128,10 +128,7 @@ aaaaaaaaaaaaaaaaaaaaa = {
     ]
 }
 
-{
-    a: a  # a
-    for c in e  # for  # c  # in  # e
-}
+{a: a for c in e}  # a  # for  # c  # in  # e
 
 {
     # above a

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

@@ -158,9 +158,7 @@ lambda x: lambda y: lambda z: (
 # Trailing
 
 
-a = (
-    lambda: 1  # Dangling
-)
+a = lambda: 1  # Dangling
 
 # Regression test: lambda empty arguments ranges were too long, leading to unstable
 # formatting

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

@@ -92,10 +92,7 @@ aaaaaaaaaaaaaaaaaaaaa = [
     ]
 ]
 
-[
-    a  # a
-    for c in e  # for  # c  # in  # e
-]
+[a for c in e]  # a  # for  # c  # in  # e
 
 [
     # above a

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

@@ -72,10 +72,7 @@ selected_choices = {
     ]
 }
 
-{
-    a  # a
-    for c in e  # for  # c  # in  # e
-}
+{a for c in e}  # a  # for  # c  # in  # e
 
 {
     # above a

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

@@ -111,8 +111,7 @@ a1 = "a"[
 a2 = "a"[
     # a
     # b
-    :  # c
-    # d
+    :  # c# d
 ]
 
 # Check all places where comments can exist
@@ -151,9 +150,7 @@ c4 = "c"[
 ]
 
 # End of line comments
-d1 = "d"[  # comment
-    :
-]
+d1 = "d"[:]  # comment
 d2 = "d"[  # comment
     1:
 ]

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

@@ -635,9 +635,7 @@ def f(arg1=1, *, kwonlyarg1, kwonlyarg2=2):
 
 
 # Regression test for https://github.com/astral-sh/ruff/issues/5176#issuecomment-1598171989
-def foo(
-    b=3 + 2,  # comment
-):
+def foo(b=3 + 2):  # comment
     ...
 
 
@@ -1039,9 +1037,7 @@ def handleMatch(  # type: ignore[override] # https://github.com/python/mypy/issu
     ...
 
 
-def double(
-    a: int,  # Hello
-) -> int:
+def double(a: int) -> int:  # Hello
     return 2 * a
 
 

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

@@ -61,11 +61,7 @@ while some_condition(unformatted, args) and anotherCondition or aThirdCondition:
     print("Do something")
 
 
-while (
-    some_condition(unformatted, args)  # trailing some condition
-    and anotherCondition
-    or aThirdCondition  # trailing third condition
-):  # comment
+while some_condition(unformatted, args) and anotherCondition or aThirdCondition:  # trailing some condition  # trailing third condition  # comment
     print("Do something")
 ```
 

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

@@ -142,10 +142,7 @@ with (
     # trailing
 
 
-with (
-    a,  # a  # comma
-    b,  # c
-):  # colon
+with a, b:  # a  # comma  # c  # colon
     ...
 
 
@@ -218,11 +215,9 @@ with (
     ...
 
 with (
-    (
-        a
-        # trailing own line comment
-    ) as b  # trailing as same line comment  # trailing b same line comment
-):
+    a
+    # trailing own line comment
+) as b:  # trailing as same line comment  # trailing b same line comment
     ...
 
 with (