diff --git a/Lib/test/test_fstring.py b/Lib/test/test_fstring.py index ea4e589929e..9048e89689d 100644 --- a/Lib/test/test_fstring.py +++ b/Lib/test/test_fstring.py @@ -725,9 +725,11 @@ def test_yield(self): # a function into a generator def fn(y): f'y:{yield y*2}' + f'{yield}' g = fn(4) self.assertEqual(next(g), 8) + self.assertEqual(next(g), None) def test_yield_send(self): def fn(x): diff --git a/Misc/NEWS.d/next/Core and Builtins/2020-06-08-01-08-57.bpo-40904.76qQzo.rst b/Misc/NEWS.d/next/Core and Builtins/2020-06-08-01-08-57.bpo-40904.76qQzo.rst new file mode 100644 index 00000000000..09009b18c63 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2020-06-08-01-08-57.bpo-40904.76qQzo.rst @@ -0,0 +1,2 @@ +Fix possible segfault in the new PEG parser when parsing f-string containing +yield statements with no value (:code:`f"{yield}"`). Patch by Pablo Galindo diff --git a/Parser/pegen/parse_string.c b/Parser/pegen/parse_string.c index efe82df4765..94241e1965e 100644 --- a/Parser/pegen/parse_string.c +++ b/Parser/pegen/parse_string.c @@ -278,6 +278,9 @@ static void fstring_shift_argument(expr_ty parent, arg_ty args, int lineno, int static inline void shift_expr(expr_ty parent, expr_ty n, int line, int col) { + if (n == NULL) { + return; + } if (parent->lineno < n->lineno) { col = 0; }