Format if statements (#4961)

crates/ruff_python_formatter/src/comments/placement.rs

@@ -215,6 +215,26 @@ fn handle_in_between_bodies_own_line_comment<'a>(
             return CommentPlacement::Default(comment);
         }
 
+        // If there's any non-trivia token between the preceding node and the comment, than it means that
+        // we're past the case of the alternate branch, defer to the default rules
+        // ```python
+        // if a:
+        //      pass
+        //  else:
+        //      # leading comment
+        //      def inline_after_else(): ...
+        // ```
+        if SimpleTokenizer::new(
+            locator.contents(),
+            TextRange::new(preceding.end(), comment.slice().start()),
+        )
+        .skip_trivia()
+        .next()
+        .is_some()
+        {
+            return CommentPlacement::Default(comment);
+        }
+
         // it now depends on the indentation level of the comment if it is a leading comment for e.g.
         // the following `elif` or indeed a trailing comment of the previous body's last statement.
         let comment_indentation =

crates/ruff_python_formatter/src/lib.rs

@@ -248,7 +248,8 @@ if    True:
 # trailing
 "#;
         let expected = r#"# preceding
-NOT_YET_IMPLEMENTED_StmtIf
+if True:
+    NOT_IMPLEMENTED_call()
 # trailing
 "#;
         let actual = format_module(input)?.as_code().to_string();
@@ -436,6 +437,11 @@ def with_leading_comment(): ...
         //     .document()
         //     .display(formatted.context().source_code()));
 
+        // dbg!(formatted
+        //     .context()
+        //     .comments()
+        //     .debug(formatted.context().source_code()));
+
         let printed = formatted.print().unwrap();
 
         assert_eq!(

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__attribute_access_on_number_literals_py.snap

@@ -35,7 +35,7 @@ y = 100(no)
 ```diff
 --- Black
 +++ Ruff
-@@ -1,22 +1,21 @@
+@@ -1,22 +1,22 @@
 -x = (123456789).bit_count()
 -x = (123456).__abs__()
 -x = (0.1).is_integer()
@@ -70,8 +70,8 @@ y = 100(no)
 +x = NOT_YET_IMPLEMENTED_ExprUnaryOp
  
 -if (10).real:
--    ...
-+NOT_YET_IMPLEMENTED_StmtIf
++if 10 .NOT_IMPLEMENTED_attr:
+     ...
  
 -y = 100[no]
 -y = 100(no)
@@ -99,7 +99,8 @@ x = 0O777 .NOT_IMPLEMENTED_attr
 x = NOT_IMPLEMENTED_call()
 x = NOT_YET_IMPLEMENTED_ExprUnaryOp
 
-NOT_YET_IMPLEMENTED_StmtIf
+if 10 .NOT_IMPLEMENTED_attr:
+    ...
 
 y = NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
 y = NOT_IMPLEMENTED_call()

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__collections_py.snap

@@ -84,7 +84,7 @@ if True:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,99 +1,46 @@
+@@ -1,99 +1,52 @@
 -import core, time, a
 +NOT_YET_IMPLEMENTED_StmtImport
  
@@ -186,14 +186,16 @@ if True:
 +division_result_tuple = (1, 2)
 +NOT_IMPLEMENTED_call()
  
--if True:
+ if True:
 -    IGNORED_TYPES_FOR_ATTRIBUTE_CHECKING = (
 -        Config.IGNORED_TYPES_FOR_ATTRIBUTE_CHECKING
 -        | {pylons.controllers.WSGIController}
 -    )
-+NOT_YET_IMPLEMENTED_StmtIf
++    IGNORED_TYPES_FOR_ATTRIBUTE_CHECKING = Config.NOT_IMPLEMENTED_attr | {
++        pylons.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr,
++    }
  
--if True:
+ if True:
 -    ec2client.get_waiter("instance_stopped").wait(
 -        InstanceIds=[instance.id],
 -        WaiterConfig={
@@ -212,7 +214,9 @@ if True:
 -            "Delay": 5,
 -        },
 -    )
-+NOT_YET_IMPLEMENTED_StmtIf
++    NOT_IMPLEMENTED_call()
++    NOT_IMPLEMENTED_call()
++    NOT_IMPLEMENTED_call()
 ```
 
 ## Ruff Output
@@ -261,9 +265,15 @@ NOT_YET_IMPLEMENTED_StmtFor
 division_result_tuple = (1, 2)
 NOT_IMPLEMENTED_call()
 
-NOT_YET_IMPLEMENTED_StmtIf
+if True:
+    IGNORED_TYPES_FOR_ATTRIBUTE_CHECKING = Config.NOT_IMPLEMENTED_attr | {
+        pylons.NOT_IMPLEMENTED_attr.NOT_IMPLEMENTED_attr,
+    }
 
-NOT_YET_IMPLEMENTED_StmtIf
+if True:
+    NOT_IMPLEMENTED_call()
+    NOT_IMPLEMENTED_call()
+    NOT_IMPLEMENTED_call()
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments2_py.snap

@@ -227,7 +227,7 @@ instruction()#comment with bad spacing
  ]
  
  not_shareables = [
-@@ -37,51 +33,24 @@
+@@ -37,50 +33,51 @@
      # builtin types and objects
      type,
      object,
@@ -249,29 +249,42 @@ instruction()#comment with bad spacing
  
 -if "PYTHON" in os.environ:
 -    add_compiler(compiler_from_env())
--else:
--    # for compiler in compilers.values():
--    # add_compiler(compiler)
++if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
++    NOT_IMPLEMENTED_call()
+ else:
+     # for compiler in compilers.values():
+     # add_compiler(compiler)
 -    add_compiler(compilers[(7.0, 32)])
--    # add_compiler(compilers[(7.1, 64)])
-+NOT_YET_IMPLEMENTED_StmtIf
++    NOT_IMPLEMENTED_call()
+     # add_compiler(compilers[(7.1, 64)])
  
  
  # Comment before function.
  def inline_comments_in_brackets_ruin_everything():
--    if typedargslist:
+     if typedargslist:
 -        parameters.children = [children[0], body, children[-1]]  # (1  # )1
 -        parameters.children = [
 -            children[0],
--            body,
++        parameters.NOT_IMPLEMENTED_attr = [
++            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],  # (1
++            body,
++            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],  # )1
++        ]
++        parameters.NOT_IMPLEMENTED_attr = [
++            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],
+             body,
 -            children[-1],  # type: ignore
--        ]
--    else:
++            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],  # type: ignore
+         ]
+     else:
 -        parameters.children = [
 -            parameters.children[0],  # (2 what if this was actually long
--            body,
++        parameters.NOT_IMPLEMENTED_attr = [
++            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],  # (2 what if this was actually long
+             body,
 -            parameters.children[-1],  # )2
--        ]
++            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],  # )2
+         ]
 -        parameters.children = [parameters.what_if_this_was_actually_long.children[0], body, parameters.children[-1]]  # type: ignore
 -    if (
 -        self._proc is not None
@@ -281,13 +294,16 @@ instruction()#comment with bad spacing
 -        # transport hasn't been notified yet?
 -        and self._proc.poll() is None
 -    ):
--        pass
-+    NOT_YET_IMPLEMENTED_StmtIf
-+    NOT_YET_IMPLEMENTED_StmtIf
++        parameters.NOT_IMPLEMENTED_attr = [
++            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],
++            body,
++            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],
++        ]  # type: ignore
++    if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+         pass
      # no newline before or after
      short = [
-         # one
-@@ -91,75 +60,26 @@
+@@ -91,75 +88,29 @@
      ]
  
      # no newline after
@@ -339,11 +355,11 @@ instruction()#comment with bad spacing
 +    lcomp2 = [i for i in []]
 +    lcomp3 = [i for i in []]
      while True:
--        if False:
+         if False:
 -            continue
--
--            # and round and round we go
-+        NOT_YET_IMPLEMENTED_StmtIf
++            NOT_YET_IMPLEMENTED_StmtContinue
+ 
+             # and round and round we go
          # and round and round we go
  
      # let's return
@@ -372,7 +388,7 @@ instruction()#comment with bad spacing
  
  
  #######################
-@@ -167,7 +87,7 @@
+@@ -167,7 +118,7 @@
  #######################
  
  
@@ -432,13 +448,41 @@ not_shareables = [
     NOT_IMPLEMENTED_call(),
 ]
 
-NOT_YET_IMPLEMENTED_StmtIf
+if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+    NOT_IMPLEMENTED_call()
+else:
+    # for compiler in compilers.values():
+    # add_compiler(compiler)
+    NOT_IMPLEMENTED_call()
+    # add_compiler(compilers[(7.1, 64)])
 
 
 # Comment before function.
 def inline_comments_in_brackets_ruin_everything():
-    NOT_YET_IMPLEMENTED_StmtIf
-    NOT_YET_IMPLEMENTED_StmtIf
+    if typedargslist:
+        parameters.NOT_IMPLEMENTED_attr = [
+            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],  # (1
+            body,
+            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],  # )1
+        ]
+        parameters.NOT_IMPLEMENTED_attr = [
+            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],
+            body,
+            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],  # type: ignore
+        ]
+    else:
+        parameters.NOT_IMPLEMENTED_attr = [
+            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],  # (2 what if this was actually long
+            body,
+            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],  # )2
+        ]
+        parameters.NOT_IMPLEMENTED_attr = [
+            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],
+            body,
+            NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key],
+        ]  # type: ignore
+    if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+        pass
     # no newline before or after
     short = [
         # one
@@ -457,7 +501,10 @@ def inline_comments_in_brackets_ruin_everything():
     lcomp2 = [i for i in []]
     lcomp3 = [i for i in []]
     while True:
-        NOT_YET_IMPLEMENTED_StmtIf
+        if False:
+            NOT_YET_IMPLEMENTED_StmtContinue
+
+            # and round and round we go
         # and round and round we go
 
     # let's return

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments3_py.snap

@@ -61,7 +61,7 @@ def func():
 ```diff
 --- Black
 +++ Ruff
-@@ -3,46 +3,13 @@
+@@ -3,46 +3,15 @@
  
  # %%
  def func():
@@ -80,7 +80,8 @@ def func():
 +    lcomp3 = [i for i in []]
      # Capture each of the exceptions in the MultiError along with each of their causes and contexts
 -    if isinstance(exc_value, MultiError):
--        embedded = []
++    if NOT_IMPLEMENTED_call():
+         embedded = []
 -        for exc in exc_value.exceptions:
 -            if exc not in _seen:
 -                embedded.append(
@@ -96,7 +97,7 @@ def func():
 -                    )
 -                    # This should be left alone (after)
 -                )
-+    NOT_YET_IMPLEMENTED_StmtIf
++        NOT_YET_IMPLEMENTED_StmtFor
  
      # everything is fine if the expression isn't nested
 -    traceback.TracebackException.from_exception(
@@ -125,7 +126,9 @@ def func():
     x = "NOT_YET_IMPLEMENTED_STRING"
     lcomp3 = [i for i in []]
     # Capture each of the exceptions in the MultiError along with each of their causes and contexts
-    NOT_YET_IMPLEMENTED_StmtIf
+    if NOT_IMPLEMENTED_call():
+        embedded = []
+        NOT_YET_IMPLEMENTED_StmtFor
 
     # everything is fine if the expression isn't nested
     NOT_IMPLEMENTED_call()

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments5_py.snap

@@ -86,46 +86,47 @@ if __name__ == "__main__":
 ```diff
 --- Black
 +++ Ruff
-@@ -1,33 +1,18 @@
+@@ -1,33 +1,20 @@
  while True:
 -    if something.changed:
 -        do.stuff()  # trailing comment
--        # Comment belongs to the `if` block.
-+    NOT_YET_IMPLEMENTED_StmtIf
++    if something.NOT_IMPLEMENTED_attr:
++        NOT_IMPLEMENTED_call()  # trailing comment
+         # Comment belongs to the `if` block.
      # This one belongs to the `while` block.
  
      # Should this one, too?  I guess so.
  
  # This one is properly standalone now.
- 
+-
 -for i in range(100):
 -    # first we do this
 -    if i % 33 == 0:
 -        break
-+NOT_YET_IMPLEMENTED_StmtFor
  
 -    # then we do this
 -    print(i)
 -    # and finally we loop around
-+NOT_YET_IMPLEMENTED_StmtWith
++NOT_YET_IMPLEMENTED_StmtFor
  
 -with open(some_temp_file) as f:
 -    data = f.read()
-+NOT_YET_IMPLEMENTED_StmtTry
- 
+-
 -try:
 -    with open(some_other_file) as w:
 -        w.write(data)
--
++NOT_YET_IMPLEMENTED_StmtWith
+ 
 -except OSError:
 -    print("problems")
--
++NOT_YET_IMPLEMENTED_StmtTry
+ 
 -import sys
 +NOT_YET_IMPLEMENTED_StmtImport
  
  
  # leading function comment
-@@ -42,7 +27,7 @@
+@@ -42,7 +29,7 @@
  # leading 1
  @deco1
  # leading 2
@@ -134,7 +135,7 @@ if __name__ == "__main__":
  # leading 3
  @deco3
  def decorated1():
-@@ -52,7 +37,7 @@
+@@ -52,7 +39,7 @@
  # leading 1
  @deco1
  # leading 2
@@ -143,20 +144,23 @@ if __name__ == "__main__":
  # leading function comment
  def decorated1():
      ...
-@@ -69,5 +54,4 @@
+@@ -69,5 +56,5 @@
      ...
  
  
 -if __name__ == "__main__":
 -    main()
-+NOT_YET_IMPLEMENTED_StmtIf
++if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
++    NOT_IMPLEMENTED_call()
 ```
 
 ## Ruff Output
 
 ```py
 while True:
-    NOT_YET_IMPLEMENTED_StmtIf
+    if something.NOT_IMPLEMENTED_attr:
+        NOT_IMPLEMENTED_call()  # trailing comment
+        # Comment belongs to the `if` block.
     # This one belongs to the `while` block.
 
     # Should this one, too?  I guess so.
@@ -211,7 +215,8 @@ def g():
     ...
 
 
-NOT_YET_IMPLEMENTED_StmtIf
+if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+    NOT_IMPLEMENTED_call()
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments9_py.snap

@@ -210,42 +210,25 @@ def bar():
  # leading 3
  @deco3
  
-@@ -98,41 +94,13 @@
- 
- 
- def main():
--    if a:
--        # Leading comment before inline function
--        def inline():
--            pass
--
--        # Another leading comment
--        def another_inline():
--            pass
-+    NOT_YET_IMPLEMENTED_StmtIf
- 
--    else:
--        # More leading comments
--        def inline_after_else():
--            pass
- 
-+NOT_YET_IMPLEMENTED_StmtIf
- 
--if a:
--    # Leading comment before "top-level inline" function
--    def top_level_quote_inline():
--        pass
- 
--    # Another leading comment
--    def another_top_level_quote_inline_inline():
--        pass
--
--else:
--    # More leading comments
--    def top_level_quote_inline_after_else():
--        pass
+@@ -106,7 +102,6 @@
+         # Another leading comment
+         def another_inline():
+             pass
 -
+     else:
+         # More leading comments
+         def inline_after_else():
+@@ -121,18 +116,13 @@
+     # Another leading comment
+     def another_top_level_quote_inline_inline():
+         pass
 -
+ else:
+     # More leading comments
+     def top_level_quote_inline_after_else():
+         pass
+ 
+ 
 -class MyClass:
 -    # First method has no empty lines between bare class def.
 -    # More comments.
@@ -356,10 +339,32 @@ def decorated_with_split_leading_comments():
 
 
 def main():
-    NOT_YET_IMPLEMENTED_StmtIf
+    if a:
+        # Leading comment before inline function
+        def inline():
+            pass
+
+        # Another leading comment
+        def another_inline():
+            pass
+    else:
+        # More leading comments
+        def inline_after_else():
+            pass
 
 
-NOT_YET_IMPLEMENTED_StmtIf
+if a:
+    # Leading comment before "top-level inline" function
+    def top_level_quote_inline():
+        pass
+
+    # Another leading comment
+    def another_top_level_quote_inline_inline():
+        pass
+else:
+    # More leading comments
+    def top_level_quote_inline_after_else():
+        pass
 
 
 NOT_YET_IMPLEMENTED_StmtClassDef

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__comments_py.snap

@@ -117,30 +117,30 @@ async def wat():
 -
 -Possibly also many, many lines.
 -"""
-+"NOT_YET_IMPLEMENTED_STRING"
- 
+-
 -import os.path
 -import sys
-+NOT_YET_IMPLEMENTED_StmtImport
-+NOT_YET_IMPLEMENTED_StmtImport
- 
+-
 -import a
 -from b.c import X  # some noqa comment
-+NOT_YET_IMPLEMENTED_StmtImport
-+NOT_YET_IMPLEMENTED_StmtImportFrom  # some noqa comment
++"NOT_YET_IMPLEMENTED_STRING"
  
 -try:
 -    import fast
 -except ImportError:
 -    import slow as fast
--
--
++NOT_YET_IMPLEMENTED_StmtImport
++NOT_YET_IMPLEMENTED_StmtImport
+ 
++NOT_YET_IMPLEMENTED_StmtImport
++NOT_YET_IMPLEMENTED_StmtImportFrom  # some noqa comment
+ 
 -# Some comment before a function.
 +NOT_YET_IMPLEMENTED_StmtTry
  y = 1
  (
      # some strings
-@@ -30,67 +21,39 @@
+@@ -30,67 +21,46 @@
  
  
  def function(default=None):
@@ -154,11 +154,13 @@ async def wat():
 +    NOT_YET_IMPLEMENTED_StmtImport
  
 -    if inner_imports.are_evil():
--        # Explains why we have this if.
--        # In great detail indeed.
++    if NOT_IMPLEMENTED_call():
+         # Explains why we have this if.
+         # In great detail indeed.
 -        x = X()
 -        return x.method1()  # type: ignore
-+    NOT_YET_IMPLEMENTED_StmtIf
++        x = NOT_IMPLEMENTED_call()
++        return NOT_IMPLEMENTED_call()  # type: ignore
  
      # This return is also commented for some reason.
      return default
@@ -171,7 +173,7 @@ async def wat():
  
  # Another comment!
  # This time two lines.
--
+ 
  
 -class Foo:
 -    """Docstring for class Foo.  Example from Sphinx docs."""
@@ -179,7 +181,7 @@ async def wat():
 -    #: Doc comment for class attribute Foo.bar.
 -    #: It can have multiple lines.
 -    bar = 1
- 
+-
 -    flox = 1.5  #: Doc comment for Foo.flox. One line only.
 -
 -    baz = 2
@@ -206,11 +208,12 @@ async def wat():
 -        result = await x.method1()
 +    NOT_YET_IMPLEMENTED_StmtAsyncWith  # Some more comments
      # Comment after ending a block.
--    if result:
+     if result:
 -        print("A OK", file=sys.stdout)
--        # Comment between things.
++        NOT_IMPLEMENTED_call()
+         # Comment between things.
 -        print()
-+    NOT_YET_IMPLEMENTED_StmtIf
++        NOT_IMPLEMENTED_call()
  
  
  # Some closing comments.
@@ -250,7 +253,11 @@ def function(default=None):
     # FIXME: Some comment about why this function is crap but still in production.
     NOT_YET_IMPLEMENTED_StmtImport
 
-    NOT_YET_IMPLEMENTED_StmtIf
+    if NOT_IMPLEMENTED_call():
+        # Explains why we have this if.
+        # In great detail indeed.
+        x = NOT_IMPLEMENTED_call()
+        return NOT_IMPLEMENTED_call()  # type: ignore
 
     # This return is also commented for some reason.
     return default
@@ -276,7 +283,10 @@ async def wat():
     # contains a trailing backslash.
     NOT_YET_IMPLEMENTED_StmtAsyncWith  # Some more comments
     # Comment after ending a block.
-    NOT_YET_IMPLEMENTED_StmtIf
+    if result:
+        NOT_IMPLEMENTED_call()
+        # Comment between things.
+        NOT_IMPLEMENTED_call()
 
 
 # Some closing comments.

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__empty_lines_py.snap

@@ -105,7 +105,7 @@ def g():
 ```diff
 --- Black
 +++ Ruff
-@@ -1,89 +1,45 @@
+@@ -1,89 +1,70 @@
 -"""Docstring."""
 +"NOT_YET_IMPLEMENTED_STRING"
  
@@ -115,31 +115,36 @@ def g():
 -    NO = ""
 -    SPACE = " "
 -    DOUBLESPACE = "  "
--
--    t = leaf.type
--    p = leaf.parent  # trailing comment
--    v = leaf.value
--
--    if t in ALWAYS_NO_SPACE:
--        pass
--    if t == token.COMMENT:  # another trailing comment
--        return DOUBLESPACE
 +    NO = "NOT_YET_IMPLEMENTED_STRING"
 +    SPACE = "NOT_YET_IMPLEMENTED_STRING"
 +    DOUBLESPACE = "NOT_YET_IMPLEMENTED_STRING"
  
--    assert p is not None, f"INTERNAL ERROR: hand-made leaf without parent: {leaf!r}"
+-    t = leaf.type
+-    p = leaf.parent  # trailing comment
+-    v = leaf.value
 +    t = leaf.NOT_IMPLEMENTED_attr
 +    p = leaf.NOT_IMPLEMENTED_attr  # trailing comment
 +    v = leaf.NOT_IMPLEMENTED_attr
  
+-    if t in ALWAYS_NO_SPACE:
++    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+         pass
+-    if t == token.COMMENT:  # another trailing comment
++    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:  # another trailing comment
+         return DOUBLESPACE
+ 
+-    assert p is not None, f"INTERNAL ERROR: hand-made leaf without parent: {leaf!r}"
++    NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -    prev = leaf.prev_sibling
 -    if not prev:
 -        prevp = preceding_leaf(p)
 -        if not prevp or prevp.type in OPENING_BRACKETS:
--            return NO
-+    NOT_YET_IMPLEMENTED_StmtIf
-+    NOT_YET_IMPLEMENTED_StmtIf  # another trailing comment
++    prev = leaf.NOT_IMPLEMENTED_attr
++    if NOT_YET_IMPLEMENTED_ExprUnaryOp:
++        prevp = NOT_IMPLEMENTED_call()
++        if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+             return NO
  
 -        if prevp.type == token.EQUAL:
 -            if prevp.parent and prevp.parent.type in {
@@ -149,8 +154,9 @@ def g():
 -                syms.arglist,
 -                syms.argument,
 -            }:
--                return NO
-+    NOT_YET_IMPLEMENTED_StmtAssert
++        if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
++            if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+                 return NO
  
 -        elif prevp.type == token.DOUBLESTAR:
 -            if prevp.parent and prevp.parent.type in {
@@ -160,9 +166,9 @@ def g():
 -                syms.arglist,
 -                syms.dictsetmaker,
 -            }:
--                return NO
-+    prev = leaf.NOT_IMPLEMENTED_attr
-+    NOT_YET_IMPLEMENTED_StmtIf
++        elif NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
++            if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+                 return NO
  
  
  ###############################################################################
@@ -188,25 +194,29 @@ def g():
      # Comment because comments
  
 -    if t in ALWAYS_NO_SPACE:
--        pass
++    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+         pass
 -    if t == token.COMMENT:
--        return DOUBLESPACE
-+    NOT_YET_IMPLEMENTED_StmtIf
-+    NOT_YET_IMPLEMENTED_StmtIf
++    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+         return DOUBLESPACE
  
      # Another comment because more comments
 -    assert p is not None, f"INTERNAL ERROR: hand-made leaf without parent: {leaf!r}"
--
++    NOT_YET_IMPLEMENTED_StmtAssert
+ 
 -    prev = leaf.prev_sibling
 -    if not prev:
 -        prevp = preceding_leaf(p)
-+    NOT_YET_IMPLEMENTED_StmtAssert
++    prev = leaf.NOT_IMPLEMENTED_attr
++    if NOT_YET_IMPLEMENTED_ExprUnaryOp:
++        prevp = NOT_IMPLEMENTED_call()
  
 -        if not prevp or prevp.type in OPENING_BRACKETS:
--            # Start of the line or a bracketed expression.
--            # More than one line for the comment.
--            return NO
--
++        if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+             # Start of the line or a bracketed expression.
+             # More than one line for the comment.
+             return NO
+ 
 -        if prevp.type == token.EQUAL:
 -            if prevp.parent and prevp.parent.type in {
 -                syms.typedargslist,
@@ -215,9 +225,9 @@ def g():
 -                syms.arglist,
 -                syms.argument,
 -            }:
--                return NO
-+    prev = leaf.NOT_IMPLEMENTED_attr
-+    NOT_YET_IMPLEMENTED_StmtIf
++        if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
++            if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+                 return NO
 ```
 
 ## Ruff Output
@@ -236,13 +246,26 @@ def f():
     p = leaf.NOT_IMPLEMENTED_attr  # trailing comment
     v = leaf.NOT_IMPLEMENTED_attr
 
-    NOT_YET_IMPLEMENTED_StmtIf
-    NOT_YET_IMPLEMENTED_StmtIf  # another trailing comment
+    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+        pass
+    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:  # another trailing comment
+        return DOUBLESPACE
 
     NOT_YET_IMPLEMENTED_StmtAssert
 
     prev = leaf.NOT_IMPLEMENTED_attr
-    NOT_YET_IMPLEMENTED_StmtIf
+    if NOT_YET_IMPLEMENTED_ExprUnaryOp:
+        prevp = NOT_IMPLEMENTED_call()
+        if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+            return NO
+
+        if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+            if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+                return NO
+
+        elif NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+            if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+                return NO
 
 
 ###############################################################################
@@ -260,14 +283,26 @@ def g():
 
     # Comment because comments
 
-    NOT_YET_IMPLEMENTED_StmtIf
-    NOT_YET_IMPLEMENTED_StmtIf
+    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+        pass
+    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+        return DOUBLESPACE
 
     # Another comment because more comments
     NOT_YET_IMPLEMENTED_StmtAssert
 
     prev = leaf.NOT_IMPLEMENTED_attr
-    NOT_YET_IMPLEMENTED_StmtIf
+    if NOT_YET_IMPLEMENTED_ExprUnaryOp:
+        prevp = NOT_IMPLEMENTED_call()
+
+        if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+            # Start of the line or a bracketed expression.
+            # More than one line for the comment.
+            return NO
+
+        if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+            if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+                return NO
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__expression_py.snap

@@ -276,7 +276,7 @@ last_call()
  Name
  None
  True
-@@ -7,346 +8,245 @@
+@@ -7,294 +8,236 @@
  1
  1.0
  1j
@@ -395,6 +395,11 @@ last_call()
 -    *a,
      4,
      5,
+-]
+-[
+-    4,
+-    *a,
+-    5,
 +    6,
 +    7,
 +    8,
@@ -403,11 +408,6 @@ last_call()
 +    (NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2),
 +    (NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2),
  ]
--[
--    4,
--    *a,
--    5,
--]
 +[1, 2, 3]
 +[NOT_YET_IMPLEMENTED_ExprStarred]
 +[NOT_YET_IMPLEMENTED_ExprStarred]
@@ -541,9 +541,6 @@ last_call()
 -    int,
 -    float,
 -    dict[str, int],
--]
--very_long_variable_name_filters: t.List[
--    t.Tuple[str, t.Union[str, t.List[t.Optional[str]]]],
 +[
 +    1,
 +    2,
@@ -558,6 +555,9 @@ last_call()
 +    NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2,
 +    NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2,
  ]
+-very_long_variable_name_filters: t.List[
+-    t.Tuple[str, t.Union[str, t.List[t.Optional[str]]]],
+-]
 -xxxx_xxxxx_xxxx_xxx: Callable[..., List[SomeClass]] = classmethod(  # type: ignore
 -    sync(async_xxxx_xxx_xxxx_xxxxx_xxxx_xxx.__func__)
 -)
@@ -756,49 +756,50 @@ last_call()
 -    and threading.current_thread() != threading.main_thread()
 -    or signal.getsignal(signal.SIGINT) != signal.default_int_handler
 -):
--    return True
--if (
--    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--    | aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--):
--    return True
--if (
--    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--    & aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--):
--    return True
--if (
--    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--    + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--):
--    return True
--if (
--    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--    - aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--):
--    return True
--if (
--    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--    * aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--):
--    return True
--if (
--    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--    / aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
--):
--    return True
--if (
++NOT_YET_IMPLEMENTED_StmtFor
++a = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
++a = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
++a = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
++a = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
++if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+     return True
+ if (
+     aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+@@ -327,24 +270,44 @@
+ ):
+     return True
+ if (
 -    ~aaaa.a + aaaa.b - aaaa.c * aaaa.d / aaaa.e
 -    | aaaa.f & aaaa.g % aaaa.h ^ aaaa.i << aaaa.k >> aaaa.l**aaaa.m // aaaa.n
--):
--    return True
--if (
++    NOT_YET_IMPLEMENTED_ExprUnaryOp
++    + aaaa.NOT_IMPLEMENTED_attr
++    - aaaa.NOT_IMPLEMENTED_attr * aaaa.NOT_IMPLEMENTED_attr / aaaa.NOT_IMPLEMENTED_attr
++    | aaaa.NOT_IMPLEMENTED_attr
++    & aaaa.NOT_IMPLEMENTED_attr % aaaa.NOT_IMPLEMENTED_attr
++    ^ aaaa.NOT_IMPLEMENTED_attr
++    << aaaa.NOT_IMPLEMENTED_attr
++    >> aaaa.NOT_IMPLEMENTED_attr**aaaa.NOT_IMPLEMENTED_attr // aaaa.NOT_IMPLEMENTED_attr
+ ):
+     return True
+ if (
 -    ~aaaaaaaa.a + aaaaaaaa.b - aaaaaaaa.c @ aaaaaaaa.d / aaaaaaaa.e
 -    | aaaaaaaa.f & aaaaaaaa.g % aaaaaaaa.h
 -    ^ aaaaaaaa.i << aaaaaaaa.k >> aaaaaaaa.l**aaaaaaaa.m // aaaaaaaa.n
--):
--    return True
--if (
++    NOT_YET_IMPLEMENTED_ExprUnaryOp
++    + aaaaaaaa.NOT_IMPLEMENTED_attr
++    - aaaaaaaa.NOT_IMPLEMENTED_attr
++    @ aaaaaaaa.NOT_IMPLEMENTED_attr
++    / aaaaaaaa.NOT_IMPLEMENTED_attr
++    | aaaaaaaa.NOT_IMPLEMENTED_attr
++    & aaaaaaaa.NOT_IMPLEMENTED_attr % aaaaaaaa.NOT_IMPLEMENTED_attr
++    ^ aaaaaaaa.NOT_IMPLEMENTED_attr
++    << aaaaaaaa.NOT_IMPLEMENTED_attr
++    >> aaaaaaaa.NOT_IMPLEMENTED_attr
++    **aaaaaaaa.NOT_IMPLEMENTED_attr
++    // aaaaaaaa.NOT_IMPLEMENTED_attr
+ ):
+     return True
+ if (
 -    ~aaaaaaaaaaaaaaaa.a
 -    + aaaaaaaaaaaaaaaa.b
 -    - aaaaaaaaaaaaaaaa.c * aaaaaaaaaaaaaaaa.d @ aaaaaaaaaaaaaaaa.e
@@ -806,27 +807,22 @@ last_call()
 -    ^ aaaaaaaaaaaaaaaa.i
 -    << aaaaaaaaaaaaaaaa.k
 -    >> aaaaaaaaaaaaaaaa.l**aaaaaaaaaaaaaaaa.m // aaaaaaaaaaaaaaaa.n
--):
--    return True
-+NOT_YET_IMPLEMENTED_StmtFor
-+a = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
-+a = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
-+a = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
-+a = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
-+NOT_YET_IMPLEMENTED_StmtIf
-+NOT_YET_IMPLEMENTED_StmtIf
-+NOT_YET_IMPLEMENTED_StmtIf
-+NOT_YET_IMPLEMENTED_StmtIf
-+NOT_YET_IMPLEMENTED_StmtIf
-+NOT_YET_IMPLEMENTED_StmtIf
-+NOT_YET_IMPLEMENTED_StmtIf
-+NOT_YET_IMPLEMENTED_StmtIf
-+NOT_YET_IMPLEMENTED_StmtIf
-+NOT_YET_IMPLEMENTED_StmtIf
++    NOT_YET_IMPLEMENTED_ExprUnaryOp
++    + aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
++    - aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
++    * aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
++    @ aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
++    | aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
++    & aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr % aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
++    ^ aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
++    << aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
++    >> aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
++    **aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
++    // aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
+ ):
+     return True
  (
-     aaaaaaaaaaaaaaaa
-     + aaaaaaaaaaaaaaaa
-@@ -363,8 +263,9 @@
+@@ -363,8 +326,9 @@
  bbbb >> bbbb * bbbb
  (
      aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
@@ -1082,16 +1078,79 @@ a = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
 a = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
 a = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
 a = NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right
-NOT_YET_IMPLEMENTED_StmtIf
-NOT_YET_IMPLEMENTED_StmtIf
-NOT_YET_IMPLEMENTED_StmtIf
-NOT_YET_IMPLEMENTED_StmtIf
-NOT_YET_IMPLEMENTED_StmtIf
-NOT_YET_IMPLEMENTED_StmtIf
-NOT_YET_IMPLEMENTED_StmtIf
-NOT_YET_IMPLEMENTED_StmtIf
-NOT_YET_IMPLEMENTED_StmtIf
-NOT_YET_IMPLEMENTED_StmtIf
+if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+    return True
+if (
+    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    | aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+):
+    return True
+if (
+    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    & aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+):
+    return True
+if (
+    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    + aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+):
+    return True
+if (
+    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    - aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+):
+    return True
+if (
+    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    * aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+):
+    return True
+if (
+    aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+    / aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
+):
+    return True
+if (
+    NOT_YET_IMPLEMENTED_ExprUnaryOp
+    + aaaa.NOT_IMPLEMENTED_attr
+    - aaaa.NOT_IMPLEMENTED_attr * aaaa.NOT_IMPLEMENTED_attr / aaaa.NOT_IMPLEMENTED_attr
+    | aaaa.NOT_IMPLEMENTED_attr
+    & aaaa.NOT_IMPLEMENTED_attr % aaaa.NOT_IMPLEMENTED_attr
+    ^ aaaa.NOT_IMPLEMENTED_attr
+    << aaaa.NOT_IMPLEMENTED_attr
+    >> aaaa.NOT_IMPLEMENTED_attr**aaaa.NOT_IMPLEMENTED_attr // aaaa.NOT_IMPLEMENTED_attr
+):
+    return True
+if (
+    NOT_YET_IMPLEMENTED_ExprUnaryOp
+    + aaaaaaaa.NOT_IMPLEMENTED_attr
+    - aaaaaaaa.NOT_IMPLEMENTED_attr
+    @ aaaaaaaa.NOT_IMPLEMENTED_attr
+    / aaaaaaaa.NOT_IMPLEMENTED_attr
+    | aaaaaaaa.NOT_IMPLEMENTED_attr
+    & aaaaaaaa.NOT_IMPLEMENTED_attr % aaaaaaaa.NOT_IMPLEMENTED_attr
+    ^ aaaaaaaa.NOT_IMPLEMENTED_attr
+    << aaaaaaaa.NOT_IMPLEMENTED_attr
+    >> aaaaaaaa.NOT_IMPLEMENTED_attr
+    **aaaaaaaa.NOT_IMPLEMENTED_attr
+    // aaaaaaaa.NOT_IMPLEMENTED_attr
+):
+    return True
+if (
+    NOT_YET_IMPLEMENTED_ExprUnaryOp
+    + aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
+    - aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
+    * aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
+    @ aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
+    | aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
+    & aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr % aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
+    ^ aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
+    << aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
+    >> aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
+    **aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
+    // aaaaaaaaaaaaaaaa.NOT_IMPLEMENTED_attr
+):
+    return True
 (
     aaaaaaaaaaaaaaaa
     + aaaaaaaaaaaaaaaa

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__fmtonoff5_py.snap

@@ -97,7 +97,7 @@ elif   unformatted:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,87 +1,33 @@
+@@ -1,33 +1,15 @@
  # Regression test for https://github.com/psf/black/issues/3129.
 -setup(
 -    entry_points={
@@ -130,25 +130,23 @@ elif   unformatted:
  def test_func():
      # yapf: disable
 -    if  unformatted(  args  ):
--        return True
--    # yapf: enable
--    elif b:
--        return True
-+    NOT_YET_IMPLEMENTED_StmtIf
- 
-     return False
- 
- 
++    if NOT_IMPLEMENTED_call():
+         return True
+     # yapf: enable
+     elif b:
+@@ -39,49 +21,27 @@
  # Regression test for https://github.com/psf/black/issues/2567.
--if True:
--    # fmt: off
+ if True:
+     # fmt: off
 -    for _ in range( 1 ):
 -    # fmt: on
 -        print ( "This won't be formatted" )
 -    print ( "This won't be formatted either" )
--else:
++    NOT_YET_IMPLEMENTED_StmtFor
++    NOT_IMPLEMENTED_call()
+ else:
 -    print("This will be formatted")
-+NOT_YET_IMPLEMENTED_StmtIf
++    NOT_IMPLEMENTED_call()
  
  
  # Regression test for https://github.com/psf/black/issues/3184.
@@ -161,14 +159,14 @@ elif   unformatted:
 -            )  :
 -                # fmt: on
 -                print ( "This won't be formatted" )
-+NOT_YET_IMPLEMENTED_StmtClassDef
- 
+-
 -            elif param[0:4] in ("ZZZZ",):
 -                print ( "This won't be formatted either" )
- 
+-
 -        print("This will be formatted")
--
--
++NOT_YET_IMPLEMENTED_StmtClassDef
+ 
+ 
  # Regression test for https://github.com/psf/black/issues/2985.
 -class Named(t.Protocol):
 -    # fmt: off
@@ -186,13 +184,14 @@ elif   unformatted:
  
  
  # Regression test for https://github.com/psf/black/issues/3436.
--if x:
--    return x
--# fmt: off
+ if x:
+     return x
+ # fmt: off
 -elif   unformatted:
--    # fmt: on
++elif unformatted:
+     # fmt: on
 -    will_be_formatted()
-+NOT_YET_IMPLEMENTED_StmtIf
++    NOT_IMPLEMENTED_call()
 ```
 
 ## Ruff Output
@@ -209,13 +208,22 @@ NOT_IMPLEMENTED_call()
 # Regression test for https://github.com/psf/black/issues/3026.
 def test_func():
     # yapf: disable
-    NOT_YET_IMPLEMENTED_StmtIf
+    if NOT_IMPLEMENTED_call():
+        return True
+    # yapf: enable
+    elif b:
+        return True
 
     return False
 
 
 # Regression test for https://github.com/psf/black/issues/2567.
-NOT_YET_IMPLEMENTED_StmtIf
+if True:
+    # fmt: off
+    NOT_YET_IMPLEMENTED_StmtFor
+    NOT_IMPLEMENTED_call()
+else:
+    NOT_IMPLEMENTED_call()
 
 
 # Regression test for https://github.com/psf/black/issues/3184.
@@ -230,7 +238,12 @@ NOT_YET_IMPLEMENTED_StmtClassDef
 
 
 # Regression test for https://github.com/psf/black/issues/3436.
-NOT_YET_IMPLEMENTED_StmtIf
+if x:
+    return x
+# fmt: off
+elif unformatted:
+    # fmt: on
+    NOT_IMPLEMENTED_call()
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__fmtonoff_py.snap

@@ -222,7 +222,7 @@ d={'a':1,
  # Comment 1
  
  # Comment 2
-@@ -18,109 +16,109 @@
+@@ -18,109 +16,111 @@
  
  # fmt: off
  def func_no_args():
@@ -237,8 +237,10 @@ d={'a':1,
 +    a
 +    b
 +    c
-+    NOT_YET_IMPLEMENTED_StmtIf
-+    NOT_YET_IMPLEMENTED_StmtIf
++    if True:
++        NOT_YET_IMPLEMENTED_StmtRaise
++    if False:
++        ...
 +    NOT_YET_IMPLEMENTED_StmtFor
 +    NOT_IMPLEMENTED_call()
 +    return None
@@ -392,7 +394,7 @@ d={'a':1,
      # fmt: off
  
      # hey, that won't work
-@@ -130,13 +128,15 @@
+@@ -130,13 +130,15 @@
  
  
  def on_and_off_broken():
@@ -413,11 +415,10 @@ d={'a':1,
      # fmt: on
      # fmt: off
      # ...but comments still get reformatted even though they should not be
-@@ -144,81 +144,18 @@
- 
+@@ -145,80 +147,21 @@
  
  def long_lines():
--    if True:
+     if True:
 -        typedargslist.extend(
 -            gen_annotated_params(
 -                ast_args.kwonlyargs,
@@ -426,11 +427,13 @@ d={'a':1,
 -                implicit_default=True,
 -            )
 -        )
--        # fmt: off
++        NOT_IMPLEMENTED_call()
+         # fmt: off
 -        a = (
 -            unnecessary_bracket()
 -        )
--        # fmt: on
++        a = NOT_IMPLEMENTED_call()
+         # fmt: on
 -    _type_comment_re = re.compile(
 -        r"""
 -        ^
@@ -455,7 +458,6 @@ d={'a':1,
 -        re.MULTILINE|re.VERBOSE
 -        # fmt: on
 -    )
-+    NOT_YET_IMPLEMENTED_StmtIf
 +    _type_comment_re = NOT_IMPLEMENTED_call()
  
  
@@ -529,8 +531,10 @@ def func_no_args():
     a
     b
     c
-    NOT_YET_IMPLEMENTED_StmtIf
-    NOT_YET_IMPLEMENTED_StmtIf
+    if True:
+        NOT_YET_IMPLEMENTED_StmtRaise
+    if False:
+        ...
     NOT_YET_IMPLEMENTED_StmtFor
     NOT_IMPLEMENTED_call()
     return None
@@ -654,7 +658,11 @@ def on_and_off_broken():
 
 
 def long_lines():
-    NOT_YET_IMPLEMENTED_StmtIf
+    if True:
+        NOT_IMPLEMENTED_call()
+        # fmt: off
+        a = NOT_IMPLEMENTED_call()
+        # fmt: on
     _type_comment_re = NOT_IMPLEMENTED_call()
 
 

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__fmtskip5_py.snap

@@ -22,7 +22,7 @@ else:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,9 +1,2 @@
+@@ -1,9 +1,5 @@
 -a, b, c = 3, 4, 5
 -if (
 -    a == 3
@@ -30,17 +30,22 @@ else:
 -    and c is not None
 -):
 -    print("I'm good!")
--else:
--    print("I'm bad")
 +(1, 2) = (1, 2)
-+NOT_YET_IMPLEMENTED_StmtIf
++if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
++    NOT_IMPLEMENTED_call()
+ else:
+-    print("I'm bad")
++    NOT_IMPLEMENTED_call()
 ```
 
 ## Ruff Output
 
 ```py
 (1, 2) = (1, 2)
-NOT_YET_IMPLEMENTED_StmtIf
+if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+    NOT_IMPLEMENTED_call()
+else:
+    NOT_IMPLEMENTED_call()
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__fmtskip8_py.snap

@@ -75,7 +75,7 @@ async def test_async_with():
 ```diff
 --- Black
 +++ Ruff
-@@ -1,62 +1,40 @@
+@@ -1,62 +1,46 @@
  # Make sure a leading comment is not removed.
 -def some_func(  unformatted,  args  ):  # fmt: skip
 -    print("I am some_func")
@@ -109,12 +109,17 @@ async def test_async_with():
  # Make sure a leading comment is not removed.
 -if  unformatted_call(  args  ):  # fmt: skip
 -    print("First branch")
--    # Make sure this is not removed.
++if NOT_IMPLEMENTED_call():  # fmt: skip
++    NOT_IMPLEMENTED_call()
+     # Make sure this is not removed.
 -elif  another_unformatted_call(  args  ):  # fmt: skip
 -    print("Second branch")
 -else  :  # fmt: skip
 -    print("Last branch")
-+NOT_YET_IMPLEMENTED_StmtIf  # fmt: skip
++elif NOT_IMPLEMENTED_call():  # fmt: skip
++    NOT_IMPLEMENTED_call()
++else:  # fmt: skip
++    NOT_IMPLEMENTED_call()
  
  
 -while  some_condition(  unformatted,  args  ):  # fmt: skip
@@ -175,7 +180,13 @@ NOT_YET_IMPLEMENTED_StmtClassDef
 
 
 # Make sure a leading comment is not removed.
-NOT_YET_IMPLEMENTED_StmtIf  # fmt: skip
+if NOT_IMPLEMENTED_call():  # fmt: skip
+    NOT_IMPLEMENTED_call()
+    # Make sure this is not removed.
+elif NOT_IMPLEMENTED_call():  # fmt: skip
+    NOT_IMPLEMENTED_call()
+else:  # fmt: skip
+    NOT_IMPLEMENTED_call()
 
 
 while NOT_IMPLEMENTED_call():  # fmt: skip

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__function2_py.snap

@@ -66,7 +66,7 @@ with hmm_but_this_should_get_two_preceding_newlines():
 ```diff
 --- Black
 +++ Ruff
-@@ -2,64 +2,27 @@
+@@ -2,64 +2,39 @@
      a,
      **kwargs,
  ) -> A:
@@ -99,42 +99,46 @@ with hmm_but_this_should_get_two_preceding_newlines():
  
  def h():
      def inner():
--        pass
--
--    print("Inner defs should breathe a little.")
--
--
--if os.name == "posix":
--    import termios
--
--    def i_should_be_followed_by_only_one_newline():
          pass
  
+-    print("Inner defs should breathe a little.")
++    NOT_IMPLEMENTED_call()
+ 
+ 
+-if os.name == "posix":
+-    import termios
++if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
++    NOT_YET_IMPLEMENTED_StmtImport
+ 
+     def i_should_be_followed_by_only_one_newline():
+         pass
+-
 -elif os.name == "nt":
 -    try:
 -        import msvcrt
-+    NOT_IMPLEMENTED_call()
- 
--        def i_should_be_followed_by_only_one_newline():
--            pass
- 
--    except ImportError:
-+NOT_YET_IMPLEMENTED_StmtIf
- 
+-
 -        def i_should_be_followed_by_only_one_newline():
 -            pass
 -
--elif False:
+-    except ImportError:
+-
+-        def i_should_be_followed_by_only_one_newline():
+-            pass
++elif NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
++    NOT_YET_IMPLEMENTED_StmtTry
+ 
+ elif False:
 -
 -    class IHopeYouAreHavingALovelyDay:
 -        def __call__(self):
 -            print("i_should_be_followed_by_only_one_newline")
 -
--else:
--
--    def foo():
--        pass
++    NOT_YET_IMPLEMENTED_StmtClassDef
+ else:
 -
+     def foo():
+         pass
+ 
 -
 -with hmm_but_this_should_get_two_preceding_newlines():
 -    pass
@@ -169,7 +173,19 @@ def h():
     NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtIf
+if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+    NOT_YET_IMPLEMENTED_StmtImport
+
+    def i_should_be_followed_by_only_one_newline():
+        pass
+elif NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+    NOT_YET_IMPLEMENTED_StmtTry
+
+elif False:
+    NOT_YET_IMPLEMENTED_StmtClassDef
+else:
+    def foo():
+        pass
 
 NOT_YET_IMPLEMENTED_StmtWith
 ```

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__function_py.snap

@@ -108,37 +108,36 @@ def __await__(): return (yield)
 ```diff
 --- Black
 +++ Ruff
-@@ -1,148 +1,94 @@
+@@ -1,12 +1,11 @@
  #!/usr/bin/env python3
 -import asyncio
 -import sys
-+NOT_YET_IMPLEMENTED_StmtImport
-+NOT_YET_IMPLEMENTED_StmtImport
- 
+-
 -from third_party import X, Y, Z
-+NOT_YET_IMPLEMENTED_StmtImportFrom
++NOT_YET_IMPLEMENTED_StmtImport
++NOT_YET_IMPLEMENTED_StmtImport
  
 -from library import some_connection, some_decorator
 +NOT_YET_IMPLEMENTED_StmtImportFrom
-+NOT_YET_IMPLEMENTED_ExprJoinedStr
  
 -f"trigger 3.6 mode"
--
++NOT_YET_IMPLEMENTED_StmtImportFrom
++NOT_YET_IMPLEMENTED_ExprJoinedStr
+ 
  
  def func_no_args():
-     a
+@@ -14,135 +13,86 @@
      b
      c
--    if True:
+     if True:
 -        raise RuntimeError
--    if False:
--        ...
++        NOT_YET_IMPLEMENTED_StmtRaise
+     if False:
+         ...
 -    for i in range(10):
 -        print(i)
 -        continue
 -    exec("new-style exec", {}, {})
-+    NOT_YET_IMPLEMENTED_StmtIf
-+    NOT_YET_IMPLEMENTED_StmtIf
 +    NOT_YET_IMPLEMENTED_StmtFor
 +    NOT_IMPLEMENTED_call()
      return None
@@ -229,7 +228,7 @@ def __await__(): return (yield)
  
  
  def long_lines():
--    if True:
+     if True:
 -        typedargslist.extend(
 -            gen_annotated_params(
 -                ast_args.kwonlyargs,
@@ -269,7 +268,8 @@ def __await__(): return (yield)
 -        """,
 -        re.MULTILINE | re.VERBOSE,
 -    )
-+    NOT_YET_IMPLEMENTED_StmtIf
++        NOT_IMPLEMENTED_call()
++        NOT_IMPLEMENTED_call()
 +    _type_comment_re = NOT_IMPLEMENTED_call()
  
  
@@ -319,8 +319,10 @@ def func_no_args():
     a
     b
     c
-    NOT_YET_IMPLEMENTED_StmtIf
-    NOT_YET_IMPLEMENTED_StmtIf
+    if True:
+        NOT_YET_IMPLEMENTED_StmtRaise
+    if False:
+        ...
     NOT_YET_IMPLEMENTED_StmtFor
     NOT_IMPLEMENTED_call()
     return None
@@ -382,7 +384,9 @@ def example(session):
 
 
 def long_lines():
-    NOT_YET_IMPLEMENTED_StmtIf
+    if True:
+        NOT_IMPLEMENTED_call()
+        NOT_IMPLEMENTED_call()
     _type_comment_re = NOT_IMPLEMENTED_call()
 
 

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__function_trailing_comma_py.snap

@@ -74,7 +74,7 @@ some_module.some_function(
 ```diff
 --- Black
 +++ Ruff
-@@ -1,69 +1,29 @@
+@@ -1,69 +1,30 @@
  def f(
      a,
  ):
@@ -130,11 +130,11 @@ some_module.some_function(
 -            "h": 8,
 -        }["a"]
 -    ):
--        pass
 +    NOT_IMPLEMENTED_call()
 +    NOT_IMPLEMENTED_call()
 +    x = NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
-+    NOT_YET_IMPLEMENTED_StmtIf
++    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+         pass
  
  
 -def xxxxxxxxxxxxxxxxxxxxxxxxxxxx() -> (
@@ -154,7 +154,7 @@ some_module.some_function(
  
  
  # The type annotation shouldn't get a trailing comma since that would change its type.
-@@ -80,35 +40,16 @@
+@@ -80,35 +41,16 @@
      pass
  
  
@@ -220,7 +220,8 @@ def f(
     NOT_IMPLEMENTED_call()
     NOT_IMPLEMENTED_call()
     x = NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]
-    NOT_YET_IMPLEMENTED_StmtIf
+    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+        pass
 
 
 def xxxxxxxxxxxxxxxxxxxxxxxxxxxx() -> NOT_IMPLEMENTED_value[NOT_IMPLEMENTED_key]:

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__power_op_spacing_py.snap

@@ -76,7 +76,7 @@ return np.divide(
 ```diff
 --- Black
 +++ Ruff
-@@ -8,56 +8,48 @@
+@@ -8,56 +8,49 @@
  
  
  def function_dont_replace_spaces():
@@ -164,7 +164,8 @@ return np.divide(
 -        out=np.full(view.sum_of_weights.shape, np.nan),  # type: ignore[union-attr]
 -        where=view.sum_of_weights**2 > view.sum_of_weights_squared,  # type: ignore[union-attr]
 -    )
-+NOT_YET_IMPLEMENTED_StmtIf
++if NOT_IMPLEMENTED_call():
++    return NOT_IMPLEMENTED_call()
  
 -return np.divide(
 -    where=view.sum_of_weights_of_weight_long**2 > view.sum_of_weights_squared,  # type: ignore
@@ -227,7 +228,8 @@ q = [i for i in []]
 
 
 # WE SHOULD DEFINITELY NOT EAT THESE COMMENTS (https://github.com/psf/black/issues/2873)
-NOT_YET_IMPLEMENTED_StmtIf
+if NOT_IMPLEMENTED_call():
+    return NOT_IMPLEMENTED_call()
 
 return NOT_IMPLEMENTED_call()
 ```

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__remove_newline_after_code_block_open_py.snap

@@ -121,7 +121,7 @@ with open("/path/to/file.txt", mode="r") as read_file:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,78 +1,64 @@
+@@ -1,78 +1,68 @@
 -import random
 +NOT_YET_IMPLEMENTED_StmtImport
  
@@ -175,18 +175,22 @@ with open("/path/to/file.txt", mode="r") as read_file:
  
 -if random.randint(0, 3) == 0:
 -    print("The new line above me is about to be removed!")
-+NOT_YET_IMPLEMENTED_StmtIf
++if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
++    NOT_IMPLEMENTED_call()
  
  
 -if random.randint(0, 3) == 0:
 -    print("The new lines above me is about to be removed!")
-+NOT_YET_IMPLEMENTED_StmtIf
++if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
++    NOT_IMPLEMENTED_call()
  
  
 -if random.randint(0, 3) == 0:
 -    if random.uniform(0, 1) > 0.5:
 -        print("Two lines above me are about to be removed!")
-+NOT_YET_IMPLEMENTED_StmtIf
++if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
++    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
++        NOT_IMPLEMENTED_call()
  
  
  while True:
@@ -259,13 +263,17 @@ NOT_YET_IMPLEMENTED_StmtFor
 NOT_YET_IMPLEMENTED_StmtFor
 
 
-NOT_YET_IMPLEMENTED_StmtIf
+if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+    NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtIf
+if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+    NOT_IMPLEMENTED_call()
 
 
-NOT_YET_IMPLEMENTED_StmtIf
+if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+        NOT_IMPLEMENTED_call()
 
 
 while True:

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__trailing_comma_optional_parens1_py.snap

@@ -38,16 +38,16 @@ class A:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,34 +1,9 @@
+@@ -1,34 +1,12 @@
 -if e1234123412341234.winerror not in (
 -    _winapi.ERROR_SEM_TIMEOUT,
 -    _winapi.ERROR_PIPE_BUSY,
 -) or _check_timeout(t):
--    pass
-+NOT_YET_IMPLEMENTED_StmtIf
++if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+     pass
  
--if x:
--    if y:
+ if x:
+     if y:
 -        new_id = (
 -            max(
 -                Vegetable.objects.order_by("-id")[0].id,
@@ -55,7 +55,7 @@ class A:
 -            )
 -            + 1
 -        )
-+NOT_YET_IMPLEMENTED_StmtIf
++        new_id = NOT_IMPLEMENTED_call() + 1
  
  
 -class X:
@@ -82,9 +82,12 @@ class A:
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtIf
+if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+    pass
 
-NOT_YET_IMPLEMENTED_StmtIf
+if x:
+    if y:
+        new_id = NOT_IMPLEMENTED_call() + 1
 
 
 NOT_YET_IMPLEMENTED_StmtClassDef

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__trailing_comma_optional_parens2_py.snap

@@ -16,20 +16,21 @@ if (e123456.get_tk_patchlevel() >= (8, 6, 0, 'final') or
 ```diff
 --- Black
 +++ Ruff
-@@ -1,6 +1 @@
+@@ -1,6 +1,2 @@
 -if e123456.get_tk_patchlevel() >= (8, 6, 0, "final") or (
 -    8,
 -    5,
 -    8,
 -) <= get_tk_patchlevel() < (8, 6):
--    pass
-+NOT_YET_IMPLEMENTED_StmtIf
++if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+     pass
 ```
 
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtIf
+if NOT_IMPLEMENTED_bool_op1 and NOT_IMPLEMENTED_bool_op2:
+    pass
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__black_test__trailing_comma_optional_parens3_py.snap

@@ -21,22 +21,31 @@ if True:
 ```diff
 --- Black
 +++ Ruff
-@@ -1,8 +1 @@
--if True:
--    if True:
--        if True:
+@@ -1,8 +1,7 @@
+ if True:
+     if True:
+         if True:
 -            return _(
 -                "qweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqweas "
 -                + "qweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqwegqweasdzxcqweasdzxc.",
 -                "qweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqweasdzxcqwe",
 -            ) % {"reported_username": reported_username, "report_reason": report_reason}
-+NOT_YET_IMPLEMENTED_StmtIf
++            return (
++                NOT_IMPLEMENTED_call()
++                % {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
++            )
 ```
 
 ## Ruff Output
 
 ```py
-NOT_YET_IMPLEMENTED_StmtIf
+if True:
+    if True:
+        if True:
+            return (
+                NOT_IMPLEMENTED_call()
+                % {NOT_IMPLEMENTED_dict_key: NOT_IMPLEMENTED_dict_value}
+            )
 ```
 
 ## Black Output

crates/ruff_python_formatter/src/snapshots/ruff_python_formatter__tests__ruff_test__statement__if_statement_py.snap

@@ -0,0 +1,88 @@
+---
+source: crates/ruff_python_formatter/src/lib.rs
+expression: snapshot
+---
+## Input
+```py
+if x == y: # trailing if condition
+    pass # trailing `pass` comment
+    # Root `if` trailing comment
+
+# Leading elif comment
+elif x < y: # trailing elif condition
+    pass
+    # `elif` trailing comment
+
+# Leading else comment
+else: # trailing else condition
+    pass
+    # `else` trailing comment
+
+
+if x == y:
+    if y == z:
+        ...
+
+    if a == b:
+        ...
+    else: # trailing comment
+        ...
+
+    # trailing else comment
+
+# leading else if comment
+elif aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + [
+    11111111111111111111111111,
+    2222222222222222222222,
+    3333333333
+    ]:
+    ...
+
+
+else:
+    ...
+```
+
+
+
+## Output
+```py
+if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:  # trailing if condition
+    pass  # trailing `pass` comment
+    # Root `if` trailing comment
+
+# Leading elif comment
+elif NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:  # trailing elif condition
+    pass
+    # `elif` trailing comment
+
+# Leading else comment
+else:  # trailing else condition
+    pass
+    # `else` trailing comment
+
+
+if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+        ...
+
+    if NOT_IMPLEMENTED_left < NOT_IMPLEMENTED_right:
+        ...
+    else:  # trailing comment
+        ...
+
+    # trailing else comment
+
+# leading else if comment
+elif aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa + [
+    11111111111111111111111111,
+    2222222222222222222222,
+    3333333333,
+]:
+    ...
+
+else:
+    ...
+```
+
+

crates/ruff_python_formatter/src/statement/stmt_if.rs

@@ -1,12 +1,130 @@
-use crate::{not_yet_implemented, FormatNodeRule, PyFormatter};
-use ruff_formatter::{write, Buffer, FormatResult};
-use rustpython_parser::ast::StmtIf;
+use crate::comments::{leading_alternate_branch_comments, trailing_comments, SourceComment};
+use crate::expression::parentheses::Parenthesize;
+use crate::prelude::*;
+use crate::FormatNodeRule;
+use ruff_formatter::{write, FormatError};
+use rustpython_parser::ast::{Ranged, Stmt, StmtIf, Suite};
 
 #[derive(Default)]
 pub struct FormatStmtIf;
 
 impl FormatNodeRule<StmtIf> for FormatStmtIf {
     fn fmt_fields(&self, item: &StmtIf, f: &mut PyFormatter) -> FormatResult<()> {
-        write!(f, [not_yet_implemented(item)])
+        let comments = f.context().comments().clone();
+
+        let mut current = IfOrElIf::If(item);
+        let mut else_comments: &[SourceComment];
+        let mut last_node_of_previous_body = None;
+
+        loop {
+            let current_statement = current.statement();
+            let StmtIf {
+                test, body, orelse, ..
+            } = current_statement;
+
+            let first_statement = body.first().ok_or(FormatError::SyntaxError)?;
+            let trailing = comments.dangling_comments(current_statement.into());
+
+            let trailing_if_comments_end = trailing
+                .partition_point(|comment| comment.slice().start() < first_statement.start());
+
+            let (if_trailing_comments, trailing_alternate_comments) =
+                trailing.split_at(trailing_if_comments_end);
+
+            if current.is_elif() {
+                let elif_leading = comments.leading_comments(current_statement.into());
+                // Manually format the leading comments because the formatting bypasses `NodeRule::fmt`
+                write!(
+                    f,
+                    [
+                        leading_alternate_branch_comments(elif_leading, last_node_of_previous_body),
+                        source_position(current_statement.start())
+                    ]
+                )?;
+            }
+
+            write!(
+                f,
+                [
+                    text(current.keyword()),
+                    space(),
+                    test.format().with_options(Parenthesize::IfBreaks),
+                    text(":"),
+                    trailing_comments(if_trailing_comments),
+                    block_indent(&body.format())
+                ]
+            )?;
+
+            // RustPython models `elif` by setting the body to a single `if` statement. The `orelse`
+            // of the most inner `if` statement then becomes the `else` of the whole `if` chain.
+            // That's why it's necessary to take the comments here from the most inner `elif`.
+            else_comments = trailing_alternate_comments;
+            last_node_of_previous_body = body.last();
+
+            if let Some(elif) = else_if(orelse) {
+                current = elif;
+            } else {
+                break;
+            }
+        }
+
+        let orelse = &current.statement().orelse;
+
+        if !orelse.is_empty() {
+            // Leading comments are always own line comments
+            let leading_else_comments_end =
+                else_comments.partition_point(|comment| comment.position().is_own_line());
+            let (else_leading, else_trailing) = else_comments.split_at(leading_else_comments_end);
+
+            write!(
+                f,
+                [
+                    leading_alternate_branch_comments(else_leading, last_node_of_previous_body),
+                    text("else:"),
+                    trailing_comments(else_trailing),
+                    block_indent(&orelse.format())
+                ]
+            )?;
+        }
+
+        Ok(())
+    }
+
+    fn fmt_dangling_comments(&self, _node: &StmtIf, _f: &mut PyFormatter) -> FormatResult<()> {
+        // Handled by `fmt_fields`
+        Ok(())
+    }
+}
+
+fn else_if(or_else: &Suite) -> Option<IfOrElIf> {
+    if let [Stmt::If(if_stmt)] = or_else.as_slice() {
+        Some(IfOrElIf::ElIf(if_stmt))
+    } else {
+        None
+    }
+}
+
+enum IfOrElIf<'a> {
+    If(&'a StmtIf),
+    ElIf(&'a StmtIf),
+}
+
+impl<'a> IfOrElIf<'a> {
+    const fn statement(&self) -> &'a StmtIf {
+        match self {
+            IfOrElIf::If(statement) => statement,
+            IfOrElIf::ElIf(statement) => statement,
+        }
+    }
+
+    const fn keyword(&self) -> &'static str {
+        match self {
+            IfOrElIf::If(_) => "if",
+            IfOrElIf::ElIf(_) => "elif",
+        }
+    }
+
+    const fn is_elif(&self) -> bool {
+        matches!(self, IfOrElIf::ElIf(_))
     }
 }