X-Git-Url: https://git.madduck.net/etc/vim.git/blobdiff_plain/98fcccee55acba04afdd933676f56927cfe9bbe4..c6800e0c659eba5b22190bf6ae0ba563a4170661:/src/black/linegen.py

diff --git a/src/black/linegen.py b/src/black/linegen.py
index c2b0616..91fdeef 100644
--- a/src/black/linegen.py
+++ b/src/black/linegen.py
@@ -3,7 +3,7 @@ Generating lines of code.
 """
 from functools import partial, wraps
 import sys
-from typing import Collection, Iterator, List, Optional, Set, Union
+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
@@ -253,6 +253,9 @@ class LineGenerator(Visitor[Line]):
             ):
                 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]:
@@ -912,6 +915,15 @@ def normalize_invisible_parens(
                     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)
@@ -923,6 +935,42 @@ 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