Implement support for PEP 646 (#3071)

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

diff --git a/src/black/lines.py b/src/black/lines.py
index 1c4e38a96c14bdcbf4d8d74f79121d677987a41e..e455a5075392e6405b6c2472c371bbce36a7d1d5 100644 (file)
--- a/src/black/lines.py
+++ b/src/black/lines.py
@@ -3,7 +3,6 @@ import itertools
 import sys
 from typing import (
     Callable,
-    Collection,
     Dict,
     Iterator,
     List,
@@ -18,12 +17,12 @@ from blib2to3.pytree import Node, Leaf
 from blib2to3.pgen2 import token
 
 from black.brackets import BracketTracker, DOT_PRIORITY
-from black.mode import Mode
+from black.mode import Mode, Preview
 from black.nodes import STANDALONE_COMMENT, TEST_DESCENDANTS
 from black.nodes import BRACKETS, OPENING_BRACKETS, CLOSING_BRACKETS
 from black.nodes import syms, whitespace, replace_child, child_towards
-from black.nodes import is_multiline_string, is_import, is_type_comment, last_two_except
-from black.nodes import is_one_tuple_between
+from black.nodes import is_multiline_string, is_import, is_type_comment
+from black.nodes import is_one_sequence_between
 
 # types
 T = TypeVar("T")
@@ -255,6 +254,7 @@ class Line:
         """Return True if we have a magic trailing comma, that is when:
         - there's a trailing comma here
         - it's not a one-tuple
+        - it's not a single-element subscript
         Additionally, if ensure_removable:
         - it's not from square bracket indexing
         """
@@ -269,6 +269,20 @@ class Line:
             return True
 
         if closing.type == token.RSQB:
+            if (
+                Preview.one_element_subscript in self.mode
+                and closing.parent
+                and closing.parent.type == syms.trailer
+                and closing.opening_bracket
+                and is_one_sequence_between(
+                    closing.opening_bracket,
+                    closing,
+                    self.leaves,
+                    brackets=(token.LSQB, token.RSQB),
+                )
+            ):
+                return False
+
             if not ensure_removable:
                 return True
             comma = self.leaves[-1]
@@ -277,7 +291,7 @@ class Line:
         if self.is_import:
             return True
 
-        if closing.opening_bracket is not None and not is_one_tuple_between(
+        if closing.opening_bracket is not None and not is_one_sequence_between(
             closing.opening_bracket, closing, self.leaves
         ):
             return True
@@ -645,7 +659,6 @@ def can_be_split(line: Line) -> bool:
 def can_omit_invisible_parens(
     line: Line,
     line_length: int,
-    omit_on_explode: Collection[LeafID] = (),
 ) -> bool:
     """Does `line` have a shape safe to reformat without optional parens around it?
 
@@ -683,12 +696,6 @@ def can_omit_invisible_parens(
 
     penultimate = line.leaves[-2]
     last = line.leaves[-1]
-    if line.magic_trailing_comma:
-        try:
-            penultimate, last = last_two_except(line.leaves, omit=omit_on_explode)
-        except LookupError:
-            # Turns out we'd omit everything.  We cannot skip the optional parentheses.
-            return False
 
     if (
         last.type == token.RPAR
@@ -710,10 +717,6 @@ def can_omit_invisible_parens(
             # unnecessary.
             return True
 
-        if line.magic_trailing_comma and penultimate.type == token.COMMA:
-            # The rightmost non-omitted bracket pair is the one we want to explode on.
-            return True
-
         if _can_omit_closing_paren(line, last=last, line_length=line_length):
             return True