gh-117557: Improve error messages when a string, bytes or bytearray of length 1 are expected (GH-117631)

1 files changed, 9 insertions, 7 deletions

diff --git a/Objects/unicodeobject.c b/Objects/unicodeobject.c
index 048f9a8..92db31f 100644
--- a/Objects/unicodeobject.c
+++ b/Objects/unicodeobject.c
@@ -14057,14 +14057,21 @@ formatchar(PyObject *v)
         if (PyUnicode_GET_LENGTH(v) == 1) {
             return PyUnicode_READ_CHAR(v, 0);
         }
-        goto onError;
+        PyErr_Format(PyExc_TypeError,
+                     "%%c requires an int or a unicode character, "
+                     "not a string of length %zd",
+                     PyUnicode_GET_LENGTH(v));
+        return (Py_UCS4) -1;
     }
     else {
         int overflow;
         long x = PyLong_AsLongAndOverflow(v, &overflow);
         if (x == -1 && PyErr_Occurred()) {
             if (PyErr_ExceptionMatches(PyExc_TypeError)) {
-                goto onError;
+                PyErr_Format(PyExc_TypeError,
+                             "%%c requires an int or a unicode character, not %T",
+                             v);
+                return (Py_UCS4) -1;
             }
             return (Py_UCS4) -1;
         }
@@ -14078,11 +14085,6 @@ formatchar(PyObject *v)
 
         return (Py_UCS4) x;
     }
-
-  onError:
-    PyErr_SetString(PyExc_TypeError,
-                    "%c requires int or char");
-    return (Py_UCS4) -1;
 }
 
 /* Parse options of an argument: flags, width, precision.