Issue #22894: TestCase.subTest() would cause the test suite to be stopped when in failfast mode, even in the absence of failures.

1 files changed, 7 insertions, 0 deletions

diff --git a/Python/formatter_unicode.c b/Python/formatter_unicode.c
index e3a8149841..056bb76902 100644
--- a/Python/formatter_unicode.c
+++ b/Python/formatter_unicode.c
@@ -846,6 +846,13 @@ format_long_internal(PyObject *value, const InternalFormatSpec *format,
                             " format specifier 'c'");
             goto done;
         }
+        /* error to request alternate format */
+        if (format->alternate) {
+            PyErr_SetString(PyExc_ValueError,
+                            "Alternate form (#) not allowed with integer"
+                            " format specifier 'c'");
+            goto done;
+        }
 
         /* taken from unicodeobject.c formatchar() */
         /* Integer input truncated to a character */