Fix crash when a tuple is used as a ContextManager (#4646)

Pedro-Muller29 · web-flow · commit d0ff3bd6cb82 · 2025-04-08T21:42:17.000-07:00
diff --git a/CHANGES.md b/CHANGES.md
@@ -15,6 +15,7 @@
 - Handle `# fmt: skip` followed by a comment at the end of file (#4635)
 - Fix crash when a tuple appears in the `as` clause of a `with` statement
   (#4634)
+- Fix crash when tuple is used as a context manager inside a `with` statement (#4646)
 
 ### Preview style
 
diff --git a/src/black/linegen.py b/src/black/linegen.py
@@ -40,6 +40,7 @@
     ensure_visible,
     fstring_to_string,
     get_annotation_type,
+    has_sibling_with_type,
     is_arith_like,
     is_async_stmt_or_funcdef,
     is_atom_with_invisible_parens,
@@ -1628,6 +1629,11 @@ def maybe_make_parens_invisible_in_atom(
         or is_empty_tuple(node)
         or is_one_tuple(node)
         or (is_tuple(node) and parent.type == syms.asexpr_test)
+        or (
+            is_tuple(node)
+            and parent.type == syms.with_stmt
+            and has_sibling_with_type(node, token.COMMA)
+        )
         or (is_yield(node) and parent.type != syms.expr_stmt)
         or (
             # This condition tries to prevent removing non-optional brackets
diff --git a/src/black/nodes.py b/src/black/nodes.py
@@ -1058,3 +1058,21 @@ def furthest_ancestor_with_last_leaf(leaf: Leaf) -> LN:
     while node.parent and node.parent.children and node is node.parent.children[-1]:
         node = node.parent
     return node
+
+
+def has_sibling_with_type(node: LN, type: int) -> bool:
+    # Check previous siblings
+    sibling = node.prev_sibling
+    while sibling is not None:
+        if sibling.type == type:
+            return True
+        sibling = sibling.prev_sibling
+
+    # Check next siblings
+    sibling = node.next_sibling
+    while sibling is not None:
+        if sibling.type == type:
+            return True
+        sibling = sibling.next_sibling
+
+    return False
diff --git a/tests/data/cases/context_managers_39.py b/tests/data/cases/context_managers_39.py
@@ -89,6 +89,26 @@ async def func():
 with (x, y) as z:
     pass
 
+
+# don't remove the brackets here, it changes the meaning of the code.
+# even though the code will always trigger a runtime error
+with (name_5, name_4), name_5:
+    pass
+
+
+def test_tuple_as_contextmanager():
+    from contextlib import nullcontext
+
+    try:
+        with (nullcontext(),nullcontext()),nullcontext():
+            pass
+    except TypeError: 
+        # test passed
+        pass
+    else:
+        # this should be a type error
+        assert False
+
 # output
 
 
@@ -182,3 +202,23 @@ async def func():
 # don't remove the brackets here, it changes the meaning of the code.
 with (x, y) as z:
     pass
+
+
+# don't remove the brackets here, it changes the meaning of the code.
+# even though the code will always trigger a runtime error
+with (name_5, name_4), name_5:
+    pass
+
+
+def test_tuple_as_contextmanager():
+    from contextlib import nullcontext
+
+    try:
+        with (nullcontext(), nullcontext()), nullcontext():
+            pass
+    except TypeError:
+        # test passed
+        pass
+    else:
+        # this should be a type error
+        assert False
