Raise error on unsupported ISO 8601 time strings

ben-c-at-moz · ben-c-at-moz · commit 3bdb0814bb83 · 2024-05-21T14:37:58.000-04:00
Some time strings that contain fractional hours or minutes are permitted by
ISO 8601, but such strings are very unlikely to be intentional. The current
parser does not parse such strings correctly or raise an error. This change
raises a ValueError when hours or minutes contain a decimal mark.
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
@@ -859,6 +859,9 @@ parse_hh_mm_ss_ff(const char *tstr, const char *tstr_end, int *hour,
             continue;
         }
         else if (c == '.' || c == ',') {
+            if (i < 2) {
+                return -3; // Decimal mark on hour or minute
+            }
             break;
         } else if (!has_separator) {
             --p;
