]> git.madduck.net Git - etc/vim.git/blobdiff - src/black/linegen.py

madduck's git repository

Every one of the projects in this repository is available at the canonical URL git://git.madduck.net/madduck/pub/<projectpath> — see each project's metadata for the exact URL.

All patches and comments are welcome. Please squash your changes to logical commits before using git-format-patch and git-send-email to patches@git.madduck.net. If you'd read over the Git project's submission guidelines and adhered to them, I'd be especially grateful.

SSH access, as well as push access can be individually arranged.

If you use my repositories frequently, consider adding the following snippet to ~/.gitconfig and using the third clone URL listed for each project:

[url "git://git.madduck.net/madduck/"]
  insteadOf = madduck:

Fix a crash in ESP where a standalone comment is placed before a dict's value (#3469)
[etc/vim.git] / src / black / linegen.py
index 2cf9cf3130a998273c0de6055775a3f5e13dc627..2e75bc945066d148f1cc03f673107cc0918e6f22 100644 (file)
@@ -1,38 +1,75 @@
 """
 Generating lines of code.
 """
 """
 Generating lines of code.
 """
-from functools import partial, wraps
 import sys
 import sys
-from typing import Collection, Iterator, List, Optional, Set, Union
+from dataclasses import dataclass
+from enum import Enum, auto
+from functools import partial, wraps
+from typing import Collection, Iterator, List, Optional, Set, Union, cast
 
 
-from black.nodes import WHITESPACE, RARROW, STATEMENT, STANDALONE_COMMENT
-from black.nodes import ASSIGNMENTS, OPENING_BRACKETS, CLOSING_BRACKETS
-from black.nodes import Visitor, syms, is_arith_like, ensure_visible
+from black.brackets import (
+    COMMA_PRIORITY,
+    DOT_PRIORITY,
+    get_leaves_inside_matching_brackets,
+    max_delimiter_priority_in_atom,
+)
+from black.comments import FMT_OFF, generate_comments, list_comments
+from black.lines import (
+    Line,
+    append_leaves,
+    can_be_split,
+    can_omit_invisible_parens,
+    is_line_short_enough,
+    line_to_string,
+)
+from black.mode import Feature, Mode, Preview
 from black.nodes import (
 from black.nodes import (
+    ASSIGNMENTS,
+    BRACKETS,
+    CLOSING_BRACKETS,
+    OPENING_BRACKETS,
+    RARROW,
+    STANDALONE_COMMENT,
+    STATEMENT,
+    WHITESPACE,
+    Visitor,
+    ensure_visible,
+    is_arith_like,
+    is_atom_with_invisible_parens,
     is_docstring,
     is_empty_tuple,
     is_docstring,
     is_empty_tuple,
-    is_one_tuple,
+    is_lpar_token,
+    is_multiline_string,
+    is_name_token,
     is_one_sequence_between,
     is_one_sequence_between,
+    is_one_tuple,
+    is_rpar_token,
+    is_stub_body,
+    is_stub_suite,
+    is_vararg,
+    is_walrus_assignment,
+    is_yield,
+    syms,
+    wrap_in_parentheses,
 )
 )
-from black.nodes import is_name_token, is_lpar_token, is_rpar_token
-from black.nodes import is_walrus_assignment, is_yield, is_vararg, is_multiline_string
-from black.nodes import is_stub_suite, is_stub_body, is_atom_with_invisible_parens
-from black.nodes import wrap_in_parentheses
-from black.brackets import max_delimiter_priority_in_atom
-from black.brackets import DOT_PRIORITY, COMMA_PRIORITY
-from black.lines import Line, line_to_string, is_line_short_enough
-from black.lines import can_omit_invisible_parens, can_be_split, append_leaves
-from black.comments import generate_comments, list_comments, FMT_OFF
 from black.numerics import normalize_numeric_literal
 from black.numerics import normalize_numeric_literal
-from black.strings import get_string_prefix, fix_docstring
-from black.strings import normalize_string_prefix, normalize_string_quotes
-from black.trans import Transformer, CannotTransform, StringMerger, StringSplitter
-from black.trans import StringParenWrapper, StringParenStripper, hug_power_op
-from black.mode import Mode, Feature, Preview
-
-from blib2to3.pytree import Node, Leaf
+from black.strings import (
+    fix_docstring,
+    get_string_prefix,
+    normalize_string_prefix,
+    normalize_string_quotes,
+)
+from black.trans import (
+    CannotTransform,
+    StringMerger,
+    StringParenStripper,
+    StringParenWrapper,
+    StringSplitter,
+    Transformer,
+    hug_power_op,
+)
 from blib2to3.pgen2 import token
 from blib2to3.pgen2 import token
-
+from blib2to3.pytree import Leaf, Node
 
 # types
 LeafID = int
 
 # types
 LeafID = int
@@ -144,6 +181,50 @@ class LineGenerator(Visitor[Line]):
 
             yield from self.visit(child)
 
 
             yield from self.visit(child)
 
+    def visit_dictsetmaker(self, node: Node) -> Iterator[Line]:
+        if Preview.wrap_long_dict_values_in_parens in self.mode:
+            for i, child in enumerate(node.children):
+                if i == 0:
+                    continue
+                if node.children[i - 1].type == token.COLON:
+                    if child.type == syms.atom and child.children[0].type == token.LPAR:
+                        if maybe_make_parens_invisible_in_atom(
+                            child,
+                            parent=node,
+                            remove_brackets_around_comma=False,
+                        ):
+                            wrap_in_parentheses(node, child, visible=False)
+                    else:
+                        wrap_in_parentheses(node, child, visible=False)
+        yield from self.visit_default(node)
+
+    def visit_funcdef(self, node: Node) -> Iterator[Line]:
+        """Visit function definition."""
+        if Preview.annotation_parens not in self.mode:
+            yield from self.visit_stmt(node, keywords={"def"}, parens=set())
+        else:
+            yield from self.line()
+
+            # Remove redundant brackets around return type annotation.
+            is_return_annotation = False
+            for child in node.children:
+                if child.type == token.RARROW:
+                    is_return_annotation = True
+                elif is_return_annotation:
+                    if child.type == syms.atom and child.children[0].type == token.LPAR:
+                        if maybe_make_parens_invisible_in_atom(
+                            child,
+                            parent=node,
+                            remove_brackets_around_comma=False,
+                        ):
+                            wrap_in_parentheses(node, child, visible=False)
+                    else:
+                        wrap_in_parentheses(node, child, visible=False)
+                    is_return_annotation = False
+
+            for child in node.children:
+                yield from self.visit(child)
+
     def visit_match_case(self, node: Node) -> Iterator[Line]:
         """Visit either a match or case statement."""
         normalize_invisible_parens(node, parens_after=set(), preview=self.mode.preview)
     def visit_match_case(self, node: Node) -> Iterator[Line]:
         """Visit either a match or case statement."""
         normalize_invisible_parens(node, parens_after=set(), preview=self.mode.preview)
@@ -193,7 +274,9 @@ class LineGenerator(Visitor[Line]):
         for child in children:
             yield from self.visit(child)
 
         for child in children:
             yield from self.visit(child)
 
-            if child.type == token.ASYNC:
+            if child.type == token.ASYNC or child.type == STANDALONE_COMMENT:
+                # STANDALONE_COMMENT happens when `# fmt: skip` is applied on the async
+                # line.
                 break
 
         internal_stmt = next(children)
                 break
 
         internal_stmt = next(children)
@@ -226,6 +309,9 @@ class LineGenerator(Visitor[Line]):
             ):
                 wrap_in_parentheses(node, leaf)
 
             ):
                 wrap_in_parentheses(node, leaf)
 
+        if Preview.remove_redundant_parens in self.mode:
+            remove_await_parens(node)
+
         yield from self.visit_default(node)
 
     def visit_SEMI(self, leaf: Leaf) -> Iterator[Line]:
         yield from self.visit_default(node)
 
     def visit_SEMI(self, leaf: Leaf) -> Iterator[Line]:
@@ -263,7 +349,24 @@ class LineGenerator(Visitor[Line]):
         if is_docstring(leaf) and "\\\n" not in leaf.value:
             # We're ignoring docstrings with backslash newline escapes because changing
             # indentation of those changes the AST representation of the code.
         if is_docstring(leaf) and "\\\n" not in leaf.value:
             # We're ignoring docstrings with backslash newline escapes because changing
             # indentation of those changes the AST representation of the code.
-            docstring = normalize_string_prefix(leaf.value)
+            if Preview.normalize_docstring_quotes_and_prefixes_properly in self.mode:
+                # There was a bug where --skip-string-normalization wouldn't stop us
+                # from normalizing docstring prefixes. To maintain stability, we can
+                # only address this buggy behaviour while the preview style is enabled.
+                if self.mode.string_normalization:
+                    docstring = normalize_string_prefix(leaf.value)
+                    # visit_default() does handle string normalization for us, but
+                    # since this method acts differently depending on quote style (ex.
+                    # see padding logic below), there's a possibility for unstable
+                    # formatting as visit_default() is called *after*. To avoid a
+                    # situation where this function formats a docstring differently on
+                    # the second pass, normalize it early.
+                    docstring = normalize_string_quotes(docstring)
+                else:
+                    docstring = leaf.value
+            else:
+                # ... otherwise, we'll keep the buggy behaviour >.<
+                docstring = normalize_string_prefix(leaf.value)
             prefix = get_string_prefix(docstring)
             docstring = docstring[len(prefix) :]  # Remove the prefix
             quote_char = docstring[0]
             prefix = get_string_prefix(docstring)
             docstring = docstring[len(prefix) :]  # Remove the prefix
             quote_char = docstring[0]
@@ -275,9 +378,9 @@ class LineGenerator(Visitor[Line]):
             quote_len = 1 if docstring[1] != quote_char else 3
             docstring = docstring[quote_len:-quote_len]
             docstring_started_empty = not docstring
             quote_len = 1 if docstring[1] != quote_char else 3
             docstring = docstring[quote_len:-quote_len]
             docstring_started_empty = not docstring
+            indent = " " * 4 * self.current_line.depth
 
             if is_multiline_string(leaf):
 
             if is_multiline_string(leaf):
-                indent = " " * 4 * self.current_line.depth
                 docstring = fix_docstring(docstring, indent)
             else:
                 docstring = docstring.strip()
                 docstring = fix_docstring(docstring, indent)
             else:
                 docstring = docstring.strip()
@@ -299,7 +402,29 @@ class LineGenerator(Visitor[Line]):
 
             # We could enforce triple quotes at this point.
             quote = quote_char * quote_len
 
             # We could enforce triple quotes at this point.
             quote = quote_char * quote_len
-            leaf.value = prefix + quote + docstring + quote
+
+            # It's invalid to put closing single-character quotes on a new line.
+            if Preview.long_docstring_quotes_on_newline in self.mode and quote_len == 3:
+                # We need to find the length of the last line of the docstring
+                # to find if we can add the closing quotes to the line without
+                # exceeding the maximum line length.
+                # If docstring is one line, we don't put the closing quotes on a
+                # separate line because it looks ugly (#3320).
+                lines = docstring.splitlines()
+                last_line_length = len(lines[-1]) if docstring else 0
+
+                # If adding closing quotes would cause the last line to exceed
+                # the maximum line length then put a line break before the
+                # closing quotes
+                if (
+                    len(lines) > 1
+                    and last_line_length + quote_len > self.mode.line_length
+                ):
+                    leaf.value = prefix + quote + docstring + "\n" + indent + quote
+                else:
+                    leaf.value = prefix + quote + docstring + quote
+            else:
+                leaf.value = prefix + quote + docstring + quote
 
         yield from self.visit_default(leaf)
 
 
         yield from self.visit_default(leaf)
 
@@ -326,7 +451,6 @@ class LineGenerator(Visitor[Line]):
         else:
             self.visit_except_clause = partial(v, keywords={"except"}, parens=Ø)
             self.visit_with_stmt = partial(v, keywords={"with"}, parens=Ø)
         else:
             self.visit_except_clause = partial(v, keywords={"except"}, parens=Ø)
             self.visit_with_stmt = partial(v, keywords={"with"}, parens=Ø)
-        self.visit_funcdef = partial(v, keywords={"def"}, parens=Ø)
         self.visit_classdef = partial(v, keywords={"class"}, parens=Ø)
         self.visit_expr_stmt = partial(v, keywords=Ø, parens=ASSIGNMENTS)
         self.visit_return_stmt = partial(v, keywords={"return"}, parens={"return"})
         self.visit_classdef = partial(v, keywords={"class"}, parens=Ø)
         self.visit_expr_stmt = partial(v, keywords=Ø, parens=ASSIGNMENTS)
         self.visit_return_stmt = partial(v, keywords={"return"}, parens={"return"})
@@ -461,6 +585,12 @@ def transform_line(
         yield line
 
 
         yield line
 
 
+class _BracketSplitComponent(Enum):
+    head = auto()
+    body = auto()
+    tail = auto()
+
+
 def left_hand_split(line: Line, _features: Collection[Feature] = ()) -> Iterator[Line]:
     """Split line into many lines, starting with the first matching bracket pair.
 
 def left_hand_split(line: Line, _features: Collection[Feature] = ()) -> Iterator[Line]:
     """Split line into many lines, starting with the first matching bracket pair.
 
@@ -478,7 +608,10 @@ def left_hand_split(line: Line, _features: Collection[Feature] = ()) -> Iterator
             current_leaves is body_leaves
             and leaf.type in CLOSING_BRACKETS
             and leaf.opening_bracket is matching_bracket
             current_leaves is body_leaves
             and leaf.type in CLOSING_BRACKETS
             and leaf.opening_bracket is matching_bracket
+            and isinstance(matching_bracket, Leaf)
         ):
         ):
+            ensure_visible(leaf)
+            ensure_visible(matching_bracket)
             current_leaves = tail_leaves if body_leaves else head_leaves
         current_leaves.append(leaf)
         if current_leaves is head_leaves:
             current_leaves = tail_leaves if body_leaves else head_leaves
         current_leaves.append(leaf)
         if current_leaves is head_leaves:
@@ -488,15 +621,32 @@ def left_hand_split(line: Line, _features: Collection[Feature] = ()) -> Iterator
     if not matching_bracket:
         raise CannotSplit("No brackets found")
 
     if not matching_bracket:
         raise CannotSplit("No brackets found")
 
-    head = bracket_split_build_line(head_leaves, line, matching_bracket)
-    body = bracket_split_build_line(body_leaves, line, matching_bracket, is_body=True)
-    tail = bracket_split_build_line(tail_leaves, line, matching_bracket)
+    head = bracket_split_build_line(
+        head_leaves, line, matching_bracket, component=_BracketSplitComponent.head
+    )
+    body = bracket_split_build_line(
+        body_leaves, line, matching_bracket, component=_BracketSplitComponent.body
+    )
+    tail = bracket_split_build_line(
+        tail_leaves, line, matching_bracket, component=_BracketSplitComponent.tail
+    )
     bracket_split_succeeded_or_raise(head, body, tail)
     for result in (head, body, tail):
         if result:
             yield result
 
 
     bracket_split_succeeded_or_raise(head, body, tail)
     for result in (head, body, tail):
         if result:
             yield result
 
 
+@dataclass
+class _RHSResult:
+    """Intermediate split result from a right hand split."""
+
+    head: Line
+    body: Line
+    tail: Line
+    opening_bracket: Leaf
+    closing_bracket: Leaf
+
+
 def right_hand_split(
     line: Line,
     line_length: int,
 def right_hand_split(
     line: Line,
     line_length: int,
@@ -511,6 +661,22 @@ def right_hand_split(
 
     Note: running this function modifies `bracket_depth` on the leaves of `line`.
     """
 
     Note: running this function modifies `bracket_depth` on the leaves of `line`.
     """
+    rhs_result = _first_right_hand_split(line, omit=omit)
+    yield from _maybe_split_omitting_optional_parens(
+        rhs_result, line, line_length, features=features, omit=omit
+    )
+
+
+def _first_right_hand_split(
+    line: Line,
+    omit: Collection[LeafID] = (),
+) -> _RHSResult:
+    """Split the line into head, body, tail starting with the last bracket pair.
+
+    Note: this function should not have side effects. It's relied upon by
+    _maybe_split_omitting_optional_parens to get an opinion whether to prefer
+    splitting on the right side of an assignment statement.
+    """
     tail_leaves: List[Leaf] = []
     body_leaves: List[Leaf] = []
     head_leaves: List[Leaf] = []
     tail_leaves: List[Leaf] = []
     body_leaves: List[Leaf] = []
     head_leaves: List[Leaf] = []
@@ -536,41 +702,81 @@ def right_hand_split(
     tail_leaves.reverse()
     body_leaves.reverse()
     head_leaves.reverse()
     tail_leaves.reverse()
     body_leaves.reverse()
     head_leaves.reverse()
-    head = bracket_split_build_line(head_leaves, line, opening_bracket)
-    body = bracket_split_build_line(body_leaves, line, opening_bracket, is_body=True)
-    tail = bracket_split_build_line(tail_leaves, line, opening_bracket)
+    head = bracket_split_build_line(
+        head_leaves, line, opening_bracket, component=_BracketSplitComponent.head
+    )
+    body = bracket_split_build_line(
+        body_leaves, line, opening_bracket, component=_BracketSplitComponent.body
+    )
+    tail = bracket_split_build_line(
+        tail_leaves, line, opening_bracket, component=_BracketSplitComponent.tail
+    )
     bracket_split_succeeded_or_raise(head, body, tail)
     bracket_split_succeeded_or_raise(head, body, tail)
+    return _RHSResult(head, body, tail, opening_bracket, closing_bracket)
+
+
+def _maybe_split_omitting_optional_parens(
+    rhs: _RHSResult,
+    line: Line,
+    line_length: int,
+    features: Collection[Feature] = (),
+    omit: Collection[LeafID] = (),
+) -> Iterator[Line]:
     if (
         Feature.FORCE_OPTIONAL_PARENTHESES not in features
         # the opening bracket is an optional paren
     if (
         Feature.FORCE_OPTIONAL_PARENTHESES not in features
         # the opening bracket is an optional paren
-        and opening_bracket.type == token.LPAR
-        and not opening_bracket.value
+        and rhs.opening_bracket.type == token.LPAR
+        and not rhs.opening_bracket.value
         # the closing bracket is an optional paren
         # the closing bracket is an optional paren
-        and closing_bracket.type == token.RPAR
-        and not closing_bracket.value
+        and rhs.closing_bracket.type == token.RPAR
+        and not rhs.closing_bracket.value
         # it's not an import (optional parens are the only thing we can split on
         # in this case; attempting a split without them is a waste of time)
         and not line.is_import
         # there are no standalone comments in the body
         # it's not an import (optional parens are the only thing we can split on
         # in this case; attempting a split without them is a waste of time)
         and not line.is_import
         # there are no standalone comments in the body
-        and not body.contains_standalone_comments(0)
+        and not rhs.body.contains_standalone_comments(0)
         # and we can actually remove the parens
         # and we can actually remove the parens
-        and can_omit_invisible_parens(body, line_length)
+        and can_omit_invisible_parens(rhs.body, line_length)
     ):
     ):
-        omit = {id(closing_bracket), *omit}
+        omit = {id(rhs.closing_bracket), *omit}
         try:
         try:
-            yield from right_hand_split(line, line_length, features=features, omit=omit)
-            return
+            # The _RHSResult Omitting Optional Parens.
+            rhs_oop = _first_right_hand_split(line, omit=omit)
+            if not (
+                Preview.prefer_splitting_right_hand_side_of_assignments in line.mode
+                # the split is right after `=`
+                and len(rhs.head.leaves) >= 2
+                and rhs.head.leaves[-2].type == token.EQUAL
+                # the left side of assignement contains brackets
+                and any(leaf.type in BRACKETS for leaf in rhs.head.leaves[:-1])
+                # the left side of assignment is short enough (the -1 is for the ending
+                # optional paren)
+                and is_line_short_enough(rhs.head, line_length=line_length - 1)
+                # the left side of assignment won't explode further because of magic
+                # trailing comma
+                and rhs.head.magic_trailing_comma is None
+                # the split by omitting optional parens isn't preferred by some other
+                # reason
+                and not _prefer_split_rhs_oop(rhs_oop, line_length=line_length)
+            ):
+                yield from _maybe_split_omitting_optional_parens(
+                    rhs_oop, line, line_length, features=features, omit=omit
+                )
+                return
 
         except CannotSplit as e:
             if not (
 
         except CannotSplit as e:
             if not (
-                can_be_split(body)
-                or is_line_short_enough(body, line_length=line_length)
+                can_be_split(rhs.body)
+                or is_line_short_enough(rhs.body, line_length=line_length)
             ):
                 raise CannotSplit(
                     "Splitting failed, body is still too long and can't be split."
                 ) from e
 
             ):
                 raise CannotSplit(
                     "Splitting failed, body is still too long and can't be split."
                 ) from e
 
-            elif head.contains_multiline_strings() or tail.contains_multiline_strings():
+            elif (
+                rhs.head.contains_multiline_strings()
+                or rhs.tail.contains_multiline_strings()
+            ):
                 raise CannotSplit(
                     "The current optional pair of parentheses is bound to fail to"
                     " satisfy the splitting algorithm because the head or the tail"
                 raise CannotSplit(
                     "The current optional pair of parentheses is bound to fail to"
                     " satisfy the splitting algorithm because the head or the tail"
@@ -578,13 +784,42 @@ def right_hand_split(
                     " line."
                 ) from e
 
                     " line."
                 ) from e
 
-    ensure_visible(opening_bracket)
-    ensure_visible(closing_bracket)
-    for result in (head, body, tail):
+    ensure_visible(rhs.opening_bracket)
+    ensure_visible(rhs.closing_bracket)
+    for result in (rhs.head, rhs.body, rhs.tail):
         if result:
             yield result
 
 
         if result:
             yield result
 
 
+def _prefer_split_rhs_oop(rhs_oop: _RHSResult, line_length: int) -> bool:
+    """
+    Returns whether we should prefer the result from a split omitting optional parens.
+    """
+    has_closing_bracket_after_assign = False
+    for leaf in reversed(rhs_oop.head.leaves):
+        if leaf.type == token.EQUAL:
+            break
+        if leaf.type in CLOSING_BRACKETS:
+            has_closing_bracket_after_assign = True
+            break
+    return (
+        # contains matching brackets after the `=` (done by checking there is a
+        # closing bracket)
+        has_closing_bracket_after_assign
+        or (
+            # the split is actually from inside the optional parens (done by checking
+            # the first line still contains the `=`)
+            any(leaf.type == token.EQUAL for leaf in rhs_oop.head.leaves)
+            # the first line is short enough
+            and is_line_short_enough(rhs_oop.head, line_length=line_length)
+        )
+        # contains unsplittable type ignore
+        or rhs_oop.head.contains_unsplittable_type_ignore()
+        or rhs_oop.body.contains_unsplittable_type_ignore()
+        or rhs_oop.tail.contains_unsplittable_type_ignore()
+    )
+
+
 def bracket_split_succeeded_or_raise(head: Line, body: Line, tail: Line) -> None:
     """Raise :exc:`CannotSplit` if the last left- or right-hand split failed.
 
 def bracket_split_succeeded_or_raise(head: Line, body: Line, tail: Line) -> None:
     """Raise :exc:`CannotSplit` if the last left- or right-hand split failed.
 
@@ -612,15 +847,23 @@ def bracket_split_succeeded_or_raise(head: Line, body: Line, tail: Line) -> None
 
 
 def bracket_split_build_line(
 
 
 def bracket_split_build_line(
-    leaves: List[Leaf], original: Line, opening_bracket: Leaf, *, is_body: bool = False
+    leaves: List[Leaf],
+    original: Line,
+    opening_bracket: Leaf,
+    *,
+    component: _BracketSplitComponent,
 ) -> Line:
     """Return a new line with given `leaves` and respective comments from `original`.
 
 ) -> Line:
     """Return a new line with given `leaves` and respective comments from `original`.
 
-    If `is_body` is True, the result line is one-indented inside brackets and as such
-    has its first leaf's prefix normalized and a trailing comma added when expected.
+    If it's the head component, brackets will be tracked so trailing commas are
+    respected.
+
+    If it's the body component, the result line is one-indented inside brackets and as
+    such has its first leaf's prefix normalized and a trailing comma added when
+    expected.
     """
     result = Line(mode=original.mode, depth=original.depth)
     """
     result = Line(mode=original.mode, depth=original.depth)
-    if is_body:
+    if component is _BracketSplitComponent.body:
         result.inside_brackets = True
         result.depth += 1
         if leaves:
         result.inside_brackets = True
         result.depth += 1
         if leaves:
@@ -658,12 +901,24 @@ def bracket_split_build_line(
                         leaves.insert(i + 1, new_comma)
                     break
 
                         leaves.insert(i + 1, new_comma)
                     break
 
+    leaves_to_track: Set[LeafID] = set()
+    if (
+        Preview.handle_trailing_commas_in_head in original.mode
+        and component is _BracketSplitComponent.head
+    ):
+        leaves_to_track = get_leaves_inside_matching_brackets(leaves)
     # Populate the line
     for leaf in leaves:
     # Populate the line
     for leaf in leaves:
-        result.append(leaf, preformatted=True)
+        result.append(
+            leaf,
+            preformatted=True,
+            track_bracket=id(leaf) in leaves_to_track,
+        )
         for comment_after in original.comments_after(leaf):
             result.append(comment_after, preformatted=True)
         for comment_after in original.comments_after(leaf):
             result.append(comment_after, preformatted=True)
-    if is_body and should_split_line(result, opening_bracket):
+    if component is _BracketSplitComponent.body and should_split_line(
+        result, opening_bracket
+    ):
         result.should_split_rhs = True
     return result
 
         result.should_split_rhs = True
     return result
 
@@ -883,6 +1138,15 @@ def normalize_invisible_parens(
                     node.insert_child(index, Leaf(token.LPAR, ""))
                     node.append_child(Leaf(token.RPAR, ""))
                 break
                     node.insert_child(index, Leaf(token.LPAR, ""))
                     node.append_child(Leaf(token.RPAR, ""))
                 break
+            elif (
+                index == 1
+                and child.type == token.STAR
+                and node.type == syms.except_clause
+            ):
+                # In except* (PEP 654), the star is actually part of
+                # of the keyword. So we need to skip the insertion of
+                # invisible parentheses to work more precisely.
+                continue
 
             elif not (isinstance(child, Leaf) and is_multiline_string(child)):
                 wrap_in_parentheses(node, child, visible=False)
 
             elif not (isinstance(child, Leaf) and is_multiline_string(child)):
                 wrap_in_parentheses(node, child, visible=False)
@@ -894,6 +1158,42 @@ def normalize_invisible_parens(
         )
 
 
         )
 
 
+def remove_await_parens(node: Node) -> None:
+    if node.children[0].type == token.AWAIT and len(node.children) > 1:
+        if (
+            node.children[1].type == syms.atom
+            and node.children[1].children[0].type == token.LPAR
+        ):
+            if maybe_make_parens_invisible_in_atom(
+                node.children[1],
+                parent=node,
+                remove_brackets_around_comma=True,
+            ):
+                wrap_in_parentheses(node, node.children[1], visible=False)
+
+            # Since await is an expression we shouldn't remove
+            # brackets in cases where this would change
+            # the AST due to operator precedence.
+            # Therefore we only aim to remove brackets around
+            # power nodes that aren't also await expressions themselves.
+            # https://peps.python.org/pep-0492/#updated-operator-precedence-table
+            # N.B. We've still removed any redundant nested brackets though :)
+            opening_bracket = cast(Leaf, node.children[1].children[0])
+            closing_bracket = cast(Leaf, node.children[1].children[-1])
+            bracket_contents = cast(Node, node.children[1].children[1])
+            if bracket_contents.type != syms.power:
+                ensure_visible(opening_bracket)
+                ensure_visible(closing_bracket)
+            elif (
+                bracket_contents.type == syms.power
+                and bracket_contents.children[0].type == token.AWAIT
+            ):
+                ensure_visible(opening_bracket)
+                ensure_visible(closing_bracket)
+                # If we are in a nested await then recurse down.
+                remove_await_parens(bracket_contents)
+
+
 def remove_with_parens(node: Node, parent: Node) -> None:
     """Recursively hide optional parens in `with` statements."""
     # Removing all unnecessary parentheses in with statements in one pass is a tad
 def remove_with_parens(node: Node, parent: Node) -> None:
     """Recursively hide optional parens in `with` statements."""
     # Removing all unnecessary parentheses in with statements in one pass is a tad
@@ -968,6 +1268,8 @@ def maybe_make_parens_invisible_in_atom(
             syms.expr_stmt,
             syms.assert_stmt,
             syms.return_stmt,
             syms.expr_stmt,
             syms.assert_stmt,
             syms.return_stmt,
+            syms.except_clause,
+            syms.funcdef,
             # these ones aren't useful to end users, but they do please fuzzers
             syms.for_stmt,
             syms.del_stmt,
             # these ones aren't useful to end users, but they do please fuzzers
             syms.for_stmt,
             syms.del_stmt,
@@ -1117,8 +1419,10 @@ def run_transformer(
 
         result.extend(transform_line(transformed_line, mode=mode, features=features))
 
 
         result.extend(transform_line(transformed_line, mode=mode, features=features))
 
+    features_set = set(features)
     if (
     if (
-        transform.__class__.__name__ != "rhs"
+        Feature.FORCE_OPTIONAL_PARENTHESES in features_set
+        or transform.__class__.__name__ != "rhs"
         or not line.bracket_tracker.invisible
         or any(bracket.value for bracket in line.bracket_tracker.invisible)
         or line.contains_multiline_strings()
         or not line.bracket_tracker.invisible
         or any(bracket.value for bracket in line.bracket_tracker.invisible)
         or line.contains_multiline_strings()
@@ -1135,7 +1439,7 @@ def run_transformer(
 
     line_copy = line.clone()
     append_leaves(line_copy, line, line.leaves)
 
     line_copy = line.clone()
     append_leaves(line_copy, line, line.leaves)
-    features_fop = set(features) | {Feature.FORCE_OPTIONAL_PARENTHESES}
+    features_fop = features_set | {Feature.FORCE_OPTIONAL_PARENTHESES}
     second_opinion = run_transformer(
         line_copy, transform, mode, features_fop, line_str=line_str
     )
     second_opinion = run_transformer(
         line_copy, transform, mode, features_fop, line_str=line_str
     )