[3.14] gh-143517: Fix an edge case in rewriting stringified starred annotations (GH-143518) (#143540)

gh-143517: Fix an edge case in rewriting stringified starred annotations (GH-143518)
(cherry picked from commit 6c9f7b4)

Co-authored-by: Bartosz Sławecki <bartosz@ilikepython.com>

Author: miss-islington

Lib/annotationlib.py

@@ -1096,7 +1096,7 @@ def _rewrite_star_unpack(arg):
     """If the given argument annotation expression is a star unpack e.g. `'*Ts'`
        rewrite it to a valid expression.
        """
-    if arg.startswith("*"):
+    if arg.lstrip().startswith("*"):
         return f"({arg},)[0]"  # E.g. (*Ts,)[0] or (*tuple[int, int],)[0]
     else:
         return arg

Lib/test/test_annotationlib.py

@@ -885,6 +885,9 @@ def test_stringized_annotations_with_star_unpack(self):
         def f(*args: "*tuple[int, ...]"): ...
         self.assertEqual(get_annotations(f, eval_str=True),
                          {'args': (*tuple[int, ...],)[0]})
+        def f(*args: " *tuple[int, ...]"): ...
+        self.assertEqual(get_annotations(f, eval_str=True),
+                         {'args': (*tuple[int, ...],)[0]})
 
 
     def test_stringized_annotations_on_wrapper(self):

Misc/NEWS.d/next/Library/2026-01-07-15-49-06.gh-issue-143517.FP5KgL.rst

@@ -0,0 +1,4 @@
+:func:`annotationlib.get_annotations` no longer raises a :exc:`SyntaxError`
+when evaluating a stringified starred annotation that starts with one
+or more whitespace characters followed by a ``*``.
+Patch by Bartosz Sławecki.