gh-116325: Raise SyntaxError rather than IndexError on ForwardRef with empty string arg (#116341)

2024-03-05 12:14:18 +03:00
parent ffcc450a9b
commit a29998a06b
3 changed files with 9 additions and 1 deletions
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -880,7 +880,7 @@ class ForwardRef(_Final, _root=True):
        # If we do `def f(*args: *Ts)`, then we'll have `arg = '*Ts'`.
        # Unfortunately, this isn't a valid expression on its own, so we
        # do the unpacking manually.
-        if arg[0] == '*':
+        if arg.startswith('*'):
            arg_to_compile = f'({arg},)[0]'  # E.g. (*Ts,)[0] or (*tuple[int, int],)[0]
        else:
            arg_to_compile = arg