Issue #3129: Trailing digits in format string are no longer ignored.
diff --git a/Modules/_struct.c b/Modules/_struct.c
index 26179cc..2e594e8 100644
--- a/Modules/_struct.c
+++ b/Modules/_struct.c
@@ -1195,8 +1195,11 @@
                 }
                 num = x;
             }
-            if (c == '\0')
-                break;
+            if (c == '\0') {
+                PyErr_SetString(StructError,
+                                "repeat count given without format specifier");
+                return -1;
+            }
         }
         else
             num = 1;