Remove unnecessary parentheses from `except` clauses (#2939)

[etc/vim.git] / src / black / linegen.py

diff --git a/src/black/linegen.py b/src/black/linegen.py
index 79475a83f0e363c5f9f223278c5a3ebdf5f7fad6..8a28c3901bbeb90dd68806f4e0adaac7241ab861 100644 (file)
--- a/src/black/linegen.py
+++ b/src/black/linegen.py
@@ -8,7 +8,12 @@ from typing import Collection, Iterator, List, Optional, Set, Union
 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.nodes import is_docstring, is_empty_tuple, is_one_tuple, is_one_tuple_between
+from black.nodes import (
+    is_docstring,
+    is_empty_tuple,
+    is_one_tuple,
+    is_one_sequence_between,
+)
 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
@@ -313,7 +318,12 @@ class LineGenerator(Visitor[Line]):
         self.visit_try_stmt = partial(
             v, keywords={"try", "except", "else", "finally"}, parens=Ø
         )
-        self.visit_except_clause = partial(v, keywords={"except"}, parens=Ø)
+        if self.mode.preview:
+            self.visit_except_clause = partial(
+                v, keywords={"except"}, parens={"except"}
+            )
+        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)
@@ -665,9 +675,9 @@ def dont_increase_indentation(split_func: Transformer) -> Transformer:
 
     @wraps(split_func)
     def split_wrapper(line: Line, features: Collection[Feature] = ()) -> Iterator[Line]:
-        for line in split_func(line, features):
-            normalize_prefix(line.leaves[0], inside_brackets=True)
-            yield line
+        for split_line in split_func(line, features):
+            normalize_prefix(split_line.leaves[0], inside_brackets=True)
+            yield split_line
 
     return split_wrapper
 
@@ -836,7 +846,11 @@ def normalize_invisible_parens(
 
         if check_lpar:
             if child.type == syms.atom:
-                if maybe_make_parens_invisible_in_atom(child, parent=node):
+                if maybe_make_parens_invisible_in_atom(
+                    child,
+                    parent=node,
+                    preview=preview,
+                ):
                     wrap_in_parentheses(node, child, visible=False)
             elif is_one_tuple(child):
                 wrap_in_parentheses(node, child, visible=True)
@@ -860,7 +874,11 @@ def normalize_invisible_parens(
         check_lpar = isinstance(child, Leaf) and child.value in parens_after
 
 
-def maybe_make_parens_invisible_in_atom(node: LN, parent: LN) -> bool:
+def maybe_make_parens_invisible_in_atom(
+    node: LN,
+    parent: LN,
+    preview: bool = False,
+) -> bool:
     """If it's safe, make the parens in the atom `node` invisible, recursively.
     Additionally, remove repeated, adjacent invisible parens from the atom `node`
     as they are redundant.
@@ -868,13 +886,23 @@ def maybe_make_parens_invisible_in_atom(node: LN, parent: LN) -> bool:
     Returns whether the node should itself be wrapped in invisible parentheses.
 
     """
+    if (
+        preview
+        and parent.type == syms.for_stmt
+        and isinstance(node.prev_sibling, Leaf)
+        and node.prev_sibling.type == token.NAME
+        and node.prev_sibling.value == "for"
+    ):
+        for_stmt_check = False
+    else:
+        for_stmt_check = True
 
     if (
         node.type != syms.atom
         or is_empty_tuple(node)
         or is_one_tuple(node)
         or (is_yield(node) and parent.type != syms.expr_stmt)
-        or max_delimiter_priority_in_atom(node) >= COMMA_PRIORITY
+        or (max_delimiter_priority_in_atom(node) >= COMMA_PRIORITY and for_stmt_check)
     ):
         return False
 
@@ -897,7 +925,7 @@ def maybe_make_parens_invisible_in_atom(node: LN, parent: LN) -> bool:
         # make parentheses invisible
         first.value = ""
         last.value = ""
-        maybe_make_parens_invisible_in_atom(middle, parent=parent)
+        maybe_make_parens_invisible_in_atom(middle, parent=parent, preview=preview)
 
         if is_atom_with_invisible_parens(middle):
             # Strip the invisible parens from `middle` by replacing
@@ -973,7 +1001,7 @@ def generate_trailers_to_omit(line: Line, line_length: int) -> Iterator[Set[Leaf
                     prev
                     and prev.type == token.COMMA
                     and leaf.opening_bracket is not None
-                    and not is_one_tuple_between(
+                    and not is_one_sequence_between(
                         leaf.opening_bracket, leaf, line.leaves
                     )
                 ):
@@ -1001,7 +1029,7 @@ def generate_trailers_to_omit(line: Line, line_length: int) -> Iterator[Set[Leaf
                 prev
                 and prev.type == token.COMMA
                 and leaf.opening_bracket is not None
-                and not is_one_tuple_between(leaf.opening_bracket, leaf, line.leaves)
+                and not is_one_sequence_between(leaf.opening_bracket, leaf, line.leaves)
             ):
                 # Never omit bracket pairs with trailing commas.
                 # We need to explode on those.