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 90728f3c87c2e60e098f65ba905e4528d39052e0..edd201a21e9f2311d3482c1183f1d100e1f073ef 100644 (file)
--- a/src/black/nodes.py
+++ b/src/black/nodes.py
@@ -3,12 +3,8 @@ blib2to3 Node/Leaf transformation-related utility functions.
 """
 
 import sys
-from typing import Generic, Iterator, List, Optional, Set, Tuple, TypeVar, Union
+from typing import Final, Generic, Iterator, List, Optional, Set, Tuple, TypeVar, Union
 
-if sys.version_info >= (3, 8):
-    from typing import Final
-else:
-    from typing_extensions import Final
 if sys.version_info >= (3, 10):
     from typing import TypeGuard
 else:
@@ -17,6 +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
@@ -175,15 +172,15 @@ 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
     which has non-trivial arguments, like arithmetic expressions or function calls.
     """
-    NO: Final = ""
-    SPACE: Final = " "
-    DOUBLESPACE: Final = "  "
+    NO: Final[str] = ""
+    SPACE: Final[str] = " "
+    DOUBLESPACE: Final[str] = "  "
     t = leaf.type
     p = leaf.parent
     v = leaf.value
@@ -349,6 +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
 
@@ -718,6 +720,11 @@ def is_multiline_string(leaf: Leaf) -> bool:
 
 def is_stub_suite(node: Node) -> bool:
     """Return True if `node` is a suite with a stub body."""
+
+    # If there is a comment, we want to keep it.
+    if node.prefix.strip():
+        return False
+
     if (
         len(node.children) != 4
         or node.children[0].type != token.NEWLINE
@@ -726,6 +733,9 @@ def is_stub_suite(node: Node) -> bool:
     ):
         return False
 
+    if node.children[3].prefix.strip():
+        return False
+
     return is_stub_body(node.children[2])
 
 
@@ -739,7 +749,8 @@ def is_stub_body(node: LN) -> bool:
 
     child = node.children[0]
     return (
-        child.type == syms.atom
+        not child.prefix.strip()
+        and child.type == syms.atom
         and len(child.children) == 3
         and all(leaf == Leaf(token.DOT, ".") for leaf in child.children)
     )
@@ -789,22 +800,54 @@ def is_import(leaf: Leaf) -> bool:
     )
 
 
-def is_with_stmt(leaf: Leaf) -> bool:
-    """Return True if the given leaf starts a with statement."""
+def is_with_or_async_with_stmt(leaf: Leaf) -> bool:
+    """Return True if the given leaf starts a with or async with statement."""
     return bool(
         leaf.type == token.NAME
         and leaf.value == "with"
         and leaf.parent
         and leaf.parent.type == syms.with_stmt
+    ) or bool(
+        leaf.type == token.ASYNC
+        and leaf.next_sibling
+        and leaf.next_sibling.type == syms.with_stmt
+    )
+
+
+def is_async_stmt_or_funcdef(leaf: Leaf) -> bool:
+    """Return True if the given leaf starts an async def/for/with statement.
+
+    Note that `async def` can be either an `async_stmt` or `async_funcdef`,
+    the latter is used when it has decorators.
+    """
+    return bool(
+        leaf.type == token.ASYNC
+        and leaf.parent
+        and leaf.parent.type in {syms.async_stmt, syms.async_funcdef}
     )
 
 
-def is_type_comment(leaf: Leaf, suffix: str = "") -> bool:
-    """Return True if the given leaf is a special comment.
-    Only returns true for type comments for now."""
+def is_type_comment(leaf: Leaf) -> bool:
+    """Return True if the given leaf is a type comment. This function should only
+    be used for general type comments (excluding ignore annotations, which should
+    use `is_type_ignore_comment`). Note that general type comments are no longer
+    used in modern version of Python, this function may be deprecated in the future."""
     t = leaf.type
     v = leaf.value
-    return t in {token.COMMENT, STANDALONE_COMMENT} and v.startswith("# type:" + suffix)
+    return t in {token.COMMENT, STANDALONE_COMMENT} and v.startswith("# type:")
+
+
+def is_type_ignore_comment(leaf: Leaf) -> bool:
+    """Return True if the given leaf is a type comment with ignore annotation."""
+    t = leaf.type
+    v = leaf.value
+    return t in {token.COMMENT, STANDALONE_COMMENT} and is_type_ignore_comment_string(v)
+
+
+def is_type_ignore_comment_string(value: str) -> bool:
+    """Return True if the given string match with type comment with
+    ignore annotation."""
+    return value.startswith("# type: ignore")
 
 
 def wrap_in_parentheses(parent: Node, child: LN, *, visible: bool = True) -> None: