Avoid removing whitespace for walrus operators within subscripts (#3823)

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

diff --git a/src/black/nodes.py b/src/black/nodes.py
index 45423b2596be6946b203151c9a93200e25eb92df..edd201a21e9f2311d3482c1183f1d100e1f073ef 100644 (file)
--- a/src/black/nodes.py
+++ b/src/black/nodes.py
@@ -13,6 +13,7 @@ else:
 from mypy_extensions import mypyc_attr
 
 from black.cache import CACHE_DIR
+from black.mode import Mode, Preview
 from black.strings import has_triple_quotes
 from blib2to3 import pygram
 from blib2to3.pgen2 import token
@@ -171,7 +172,7 @@ class Visitor(Generic[T]):
                 yield from self.visit(child)
 
 
-def whitespace(leaf: Leaf, *, complex_subscript: bool) -> str:  # noqa: C901
+def whitespace(leaf: Leaf, *, complex_subscript: bool, mode: Mode) -> str:  # noqa: C901
     """Return whitespace prefix if needed for the given `leaf`.
 
     `complex_subscript` signals whether the given leaf is part of a subscription
@@ -345,6 +346,11 @@ def whitespace(leaf: Leaf, *, complex_subscript: bool) -> str:  # noqa: C901
 
             return NO
 
+        elif Preview.walrus_subscript in mode and (
+            t == token.COLONEQUAL or prev.type == token.COLONEQUAL
+        ):
+            return SPACE
+
         elif not complex_subscript:
             return NO