https://github.com/python/cpython/commit/968f6e523afb9840d96cc18ba2eae7fdc7856b44
commit: 968f6e523afb9840d96cc18ba2eae7fdc7856b44
branch: main
author: Semyon Moroz <[email protected]>
committer: serhiy-storchaka <[email protected]>
date: 2025-08-14T11:04:41+03:00
summary:
gh-130821: Add type information to error messages for invalid return type
(GH-130835)
files:
A
Misc/NEWS.d/next/Core_and_Builtins/2025-04-28-18-59-11.gh-issue-130821.B11LU1.rst
M Lib/test/test_coroutines.py
M Lib/test/test_type_annotations.py
M Objects/abstract.c
M Objects/bytesobject.c
M Objects/complexobject.c
M Objects/fileobject.c
M Objects/floatobject.c
M Objects/funcobject.c
M Objects/genobject.c
M Objects/iterobject.c
M Objects/moduleobject.c
M Objects/object.c
M Objects/typeobject.c
diff --git a/Lib/test/test_coroutines.py b/Lib/test/test_coroutines.py
index 42b13064befaa9..6ad7e7994f32b0 100644
--- a/Lib/test/test_coroutines.py
+++ b/Lib/test/test_coroutines.py
@@ -1008,7 +1008,7 @@ async def foo():
return (await Awaitable())
with self.assertRaisesRegex(
- TypeError, "__await__.*returned non-iterator of type"):
+ TypeError, "__await__.*must return an iterator, not"):
run_async(foo())
@@ -1106,7 +1106,7 @@ async def foo():
return await Awaitable()
with self.assertRaisesRegex(
- TypeError, r"__await__\(\) returned a coroutine"):
+ TypeError, r"__await__\(\) must return an iterator, not
coroutine"):
run_async(foo())
c.close()
@@ -1120,7 +1120,7 @@ async def foo():
return await Awaitable()
with self.assertRaisesRegex(
- TypeError, "__await__.*returned non-iterator of type"):
+ TypeError, "__await__.*must return an iterator, not"):
run_async(foo())
@@ -2490,7 +2490,7 @@ async def foo():
return (await future)
with self.assertRaisesRegex(
- TypeError, "__await__.*returned non-iterator of type 'int'"):
+ TypeError, "__await__.*must return an iterator, not int"):
self.assertEqual(foo().send(None), 1)
diff --git a/Lib/test/test_type_annotations.py
b/Lib/test/test_type_annotations.py
index c66cb058552643..1415bbca22707c 100644
--- a/Lib/test/test_type_annotations.py
+++ b/Lib/test/test_type_annotations.py
@@ -309,7 +309,7 @@ def check_annotations(self, f):
print(f.__annotations__)
f.__annotate__ = lambda x: 42
- with self.assertRaisesRegex(TypeError, r"__annotate__ returned
non-dict of type 'int'"):
+ with self.assertRaisesRegex(TypeError, r"__annotate__\(\) must return
a dict, not int"):
print(f.__annotations__)
f.__annotate__ = lambda x: {"x": x}
diff --git
a/Misc/NEWS.d/next/Core_and_Builtins/2025-04-28-18-59-11.gh-issue-130821.B11LU1.rst
b/Misc/NEWS.d/next/Core_and_Builtins/2025-04-28-18-59-11.gh-issue-130821.B11LU1.rst
new file mode 100644
index 00000000000000..09ffaf80a6d535
--- /dev/null
+++
b/Misc/NEWS.d/next/Core_and_Builtins/2025-04-28-18-59-11.gh-issue-130821.B11LU1.rst
@@ -0,0 +1,2 @@
+Enhance wrong type error messages and make them more consistent. Patch by
+Semyon Moroz.
diff --git a/Objects/abstract.c b/Objects/abstract.c
index df96b935eccb44..8adad8407d04d4 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -132,8 +132,9 @@ PyObject_LengthHint(PyObject *o, Py_ssize_t defaultvalue)
return defaultvalue;
}
if (!PyLong_Check(result)) {
- PyErr_Format(PyExc_TypeError, "__length_hint__ must be an integer, not
%.100s",
- Py_TYPE(result)->tp_name);
+ PyErr_Format(PyExc_TypeError,
+ "%T.__length_hint__() must return an int, not %T",
+ o, result);
Py_DECREF(result);
return -1;
}
@@ -143,7 +144,8 @@ PyObject_LengthHint(PyObject *o, Py_ssize_t defaultvalue)
return -1;
}
if (res < 0) {
- PyErr_Format(PyExc_ValueError, "__length_hint__() should return >= 0");
+ PyErr_Format(PyExc_ValueError,
+ "%T.__length_hint__() must return a non-negative int", o);
return -1;
}
return res;
@@ -887,8 +889,8 @@ PyObject_Format(PyObject *obj, PyObject *format_spec)
if (result && !PyUnicode_Check(result)) {
PyErr_Format(PyExc_TypeError,
- "__format__ must return a str, not %.200s",
- Py_TYPE(result)->tp_name);
+ "%T.__format__() must return a str, not %T",
+ obj, result);
Py_SETREF(result, NULL);
goto done;
}
@@ -1421,17 +1423,17 @@ _PyNumber_Index(PyObject *item)
if (!PyLong_Check(result)) {
PyErr_Format(PyExc_TypeError,
- "__index__ returned non-int (type %.200s)",
- Py_TYPE(result)->tp_name);
+ "%T.__index__() must return an int, not %T",
+ item, result);
Py_DECREF(result);
return NULL;
}
/* Issue #17576: warn if 'result' not of exact type int. */
if (PyErr_WarnFormat(PyExc_DeprecationWarning, 1,
- "__index__ returned non-int (type %.200s). "
+ "%T.__index__() must return an int, not %T. "
"The ability to return an instance of a strict subclass of int "
"is deprecated, and may be removed in a future version of Python.",
- Py_TYPE(result)->tp_name)) {
+ item, result)) {
Py_DECREF(result);
return NULL;
}
@@ -1531,17 +1533,17 @@ PyNumber_Long(PyObject *o)
if (!PyLong_Check(result)) {
PyErr_Format(PyExc_TypeError,
- "__int__ returned non-int (type %.200s)",
- Py_TYPE(result)->tp_name);
+ "%T.__int__() must return an int, not %T",
+ o, result);
Py_DECREF(result);
return NULL;
}
/* Issue #17576: warn if 'result' not of exact type int. */
if (PyErr_WarnFormat(PyExc_DeprecationWarning, 1,
- "__int__ returned non-int (type %.200s). "
+ "%T.__int__() must return an int, not %T. "
"The ability to return an instance of a strict subclass of int
"
"is deprecated, and may be removed in a future version of
Python.",
- Py_TYPE(result)->tp_name)) {
+ o, result)) {
Py_DECREF(result);
return NULL;
}
@@ -1609,17 +1611,16 @@ PyNumber_Float(PyObject *o)
if (!PyFloat_Check(res)) {
PyErr_Format(PyExc_TypeError,
- "%.50s.__float__ returned non-float (type %.50s)",
- Py_TYPE(o)->tp_name, Py_TYPE(res)->tp_name);
+ "%T.__float__() must return a float, not %T", o, res);
Py_DECREF(res);
return NULL;
}
/* Issue #26983: warn if 'res' not of exact type float. */
if (PyErr_WarnFormat(PyExc_DeprecationWarning, 1,
- "%.50s.__float__ returned non-float (type %.50s). "
+ "%T.__float__() must return a float, not %T. "
"The ability to return an instance of a strict subclass of
float "
"is deprecated, and may be removed in a future version of
Python.",
- Py_TYPE(o)->tp_name, Py_TYPE(res)->tp_name)) {
+ o, res)) {
Py_DECREF(res);
return NULL;
}
@@ -2435,10 +2436,8 @@ method_output_as_list(PyObject *o, PyObject *meth)
PyThreadState *tstate = _PyThreadState_GET();
if (_PyErr_ExceptionMatches(tstate, PyExc_TypeError)) {
_PyErr_Format(tstate, PyExc_TypeError,
- "%.200s.%U() returned a non-iterable (type %.200s)",
- Py_TYPE(o)->tp_name,
- meth,
- Py_TYPE(meth_output)->tp_name);
+ "%T.%U() must return an iterable, not %T",
+ o, meth, meth_output);
}
Py_DECREF(meth_output);
return NULL;
@@ -2818,9 +2817,8 @@ PyObject_GetIter(PyObject *o)
PyObject *res = (*f)(o);
if (res != NULL && !PyIter_Check(res)) {
PyErr_Format(PyExc_TypeError,
- "iter() returned non-iterator "
- "of type '%.100s'",
- Py_TYPE(res)->tp_name);
+ "%T.__iter__() must return an iterator, not %T",
+ o, res);
Py_SETREF(res, NULL);
}
return res;
@@ -2839,8 +2837,8 @@ PyObject_GetAIter(PyObject *o) {
PyObject *it = (*f)(o);
if (it != NULL && !PyAIter_Check(it)) {
PyErr_Format(PyExc_TypeError,
- "aiter() returned not an async iterator of type '%.100s'",
- Py_TYPE(it)->tp_name);
+ "%T.__aiter__() must return an async iterator, not %T",
+ o, it);
Py_SETREF(it, NULL);
}
return it;
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 87ea1162e03513..933a371f6bbcc0 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -566,8 +566,8 @@ format_obj(PyObject *v, const char **pbuf, Py_ssize_t *plen)
return NULL;
if (!PyBytes_Check(result)) {
PyErr_Format(PyExc_TypeError,
- "__bytes__ returned non-bytes (type %.200s)",
- Py_TYPE(result)->tp_name);
+ "%T.__bytes__() must return a bytes, not %T",
+ v, result);
Py_DECREF(result);
return NULL;
}
@@ -2793,8 +2793,8 @@ bytes_new_impl(PyTypeObject *type, PyObject *x, const
char *encoding,
return NULL;
if (!PyBytes_Check(bytes)) {
PyErr_Format(PyExc_TypeError,
- "__bytes__ returned non-bytes (type %.200s)",
- Py_TYPE(bytes)->tp_name);
+ "%T.__bytes__() must return a bytes, not %T",
+ x, bytes);
Py_DECREF(bytes);
return NULL;
}
diff --git a/Objects/complexobject.c b/Objects/complexobject.c
index b66ebe131ae605..9a5e11289a30a7 100644
--- a/Objects/complexobject.c
+++ b/Objects/complexobject.c
@@ -515,17 +515,17 @@ try_complex_special_method(PyObject *op)
}
if (!PyComplex_Check(res)) {
PyErr_Format(PyExc_TypeError,
- "__complex__ returned non-complex (type %.200s)",
- Py_TYPE(res)->tp_name);
+ "%T.__complex__() must return a complex, not %T",
+ op, res);
Py_DECREF(res);
return NULL;
}
/* Issue #29894: warn if 'res' not of exact type complex. */
if (PyErr_WarnFormat(PyExc_DeprecationWarning, 1,
- "__complex__ returned non-complex (type %.200s). "
+ "%T.__complex__() must return a complex, not %T. "
"The ability to return an instance of a strict subclass of
complex "
"is deprecated, and may be removed in a future version of
Python.",
- Py_TYPE(res)->tp_name)) {
+ op, res)) {
Py_DECREF(res);
return NULL;
}
diff --git a/Objects/fileobject.c b/Objects/fileobject.c
index e624405bd5f62f..05c3e75b4642ee 100644
--- a/Objects/fileobject.c
+++ b/Objects/fileobject.c
@@ -68,9 +68,9 @@ PyFile_GetLine(PyObject *f, int n)
}
if (result != NULL && !PyBytes_Check(result) &&
!PyUnicode_Check(result)) {
+ PyErr_Format(PyExc_TypeError,
+ "%T.readline() must return a str, not %T", f, result);
Py_SETREF(result, NULL);
- PyErr_SetString(PyExc_TypeError,
- "object.readline() returned non-string");
}
if (n < 0 && result != NULL && PyBytes_Check(result)) {
@@ -193,8 +193,8 @@ PyObject_AsFileDescriptor(PyObject *o)
Py_DECREF(fno);
}
else {
- PyErr_SetString(PyExc_TypeError,
- "fileno() returned a non-integer");
+ PyErr_Format(PyExc_TypeError,
+ "%T.fileno() must return an int, not %T", o, fno);
Py_DECREF(fno);
return -1;
}
diff --git a/Objects/floatobject.c b/Objects/floatobject.c
index 93e1973d6b32fc..4e54e0829d3def 100644
--- a/Objects/floatobject.c
+++ b/Objects/floatobject.c
@@ -288,16 +288,16 @@ PyFloat_AsDouble(PyObject *op)
if (!PyFloat_CheckExact(res)) {
if (!PyFloat_Check(res)) {
PyErr_Format(PyExc_TypeError,
- "%.50s.__float__ returned non-float (type %.50s)",
- Py_TYPE(op)->tp_name, Py_TYPE(res)->tp_name);
+ "%T.__float__() must return a float, not %T",
+ op, res);
Py_DECREF(res);
return -1;
}
if (PyErr_WarnFormat(PyExc_DeprecationWarning, 1,
- "%.50s.__float__ returned non-float (type %.50s). "
+ "%T.__float__() must return a float, not %T. "
"The ability to return an instance of a strict subclass of
float "
"is deprecated, and may be removed in a future version of
Python.",
- Py_TYPE(op)->tp_name, Py_TYPE(res)->tp_name)) {
+ op, res)) {
Py_DECREF(res);
return -1;
}
diff --git a/Objects/funcobject.c b/Objects/funcobject.c
index 9532c21fc7082e..d8a10075578087 100644
--- a/Objects/funcobject.c
+++ b/Objects/funcobject.c
@@ -560,8 +560,9 @@ func_get_annotation_dict(PyFunctionObject *op)
return NULL;
}
if (!PyDict_Check(ann_dict)) {
- PyErr_Format(PyExc_TypeError, "__annotate__ returned non-dict of
type '%.100s'",
- Py_TYPE(ann_dict)->tp_name);
+ PyErr_Format(PyExc_TypeError,
+ "__annotate__() must return a dict, not %T",
+ ann_dict);
Py_DECREF(ann_dict);
return NULL;
}
diff --git a/Objects/genobject.c b/Objects/genobject.c
index 3e7d6257006cfd..bcde9e1a7be07e 100644
--- a/Objects/genobject.c
+++ b/Objects/genobject.c
@@ -1092,14 +1092,14 @@ _PyCoro_GetAwaitableIter(PyObject *o)
if (PyCoro_CheckExact(res) || gen_is_coroutine(res)) {
/* __await__ must return an *iterator*, not
a coroutine or another awaitable (see PEP 492) */
- PyErr_SetString(PyExc_TypeError,
- "__await__() returned a coroutine");
+ PyErr_Format(PyExc_TypeError,
+ "%T.__await__() must return an iterator, "
+ "not coroutine", o);
Py_CLEAR(res);
} else if (!PyIter_Check(res)) {
PyErr_Format(PyExc_TypeError,
- "__await__() returned non-iterator "
- "of type '%.100s'",
- Py_TYPE(res)->tp_name);
+ "%T.__await__() must return an iterator, "
+ "not %T", o, res);
Py_CLEAR(res);
}
}
diff --git a/Objects/iterobject.c b/Objects/iterobject.c
index 5712e02ae828ab..e323987601d5d4 100644
--- a/Objects/iterobject.c
+++ b/Objects/iterobject.c
@@ -357,8 +357,9 @@ anextawaitable_getiter(anextawaitableobject *obj)
}
Py_SETREF(awaitable, new_awaitable);
if (!PyIter_Check(awaitable)) {
- PyErr_SetString(PyExc_TypeError,
- "__await__ returned a non-iterable");
+ PyErr_Format(PyExc_TypeError,
+ "%T.__await__() must return an iterable, not %T",
+ obj, awaitable);
Py_DECREF(awaitable);
return NULL;
}
diff --git a/Objects/moduleobject.c b/Objects/moduleobject.c
index 862395e7881870..47681e4251849c 100644
--- a/Objects/moduleobject.c
+++ b/Objects/moduleobject.c
@@ -1329,8 +1329,9 @@ module_get_annotations(PyObject *self, void
*Py_UNUSED(ignored))
return NULL;
}
if (!PyDict_Check(annotations)) {
- PyErr_Format(PyExc_TypeError, "__annotate__ returned non-dict
of type '%.100s'",
- Py_TYPE(annotations)->tp_name);
+ PyErr_Format(PyExc_TypeError,
+ "__annotate__() must return a dict, not %T",
+ annotations);
Py_DECREF(annotate);
Py_DECREF(annotations);
Py_DECREF(dict);
diff --git a/Objects/object.c b/Objects/object.c
index 479f4176a46039..fba86e63cd4a11 100644
--- a/Objects/object.c
+++ b/Objects/object.c
@@ -784,8 +784,7 @@ PyObject_Repr(PyObject *v)
}
if (!PyUnicode_Check(res)) {
_PyErr_Format(tstate, PyExc_TypeError,
- "__repr__ returned non-string (type %.200s)",
- Py_TYPE(res)->tp_name);
+ "%T.__repr__() must return a str, not %T", v, res);
Py_DECREF(res);
return NULL;
}
@@ -827,8 +826,7 @@ PyObject_Str(PyObject *v)
}
if (!PyUnicode_Check(res)) {
_PyErr_Format(tstate, PyExc_TypeError,
- "__str__ returned non-string (type %.200s)",
- Py_TYPE(res)->tp_name);
+ "%T.__str__() must return a str, not %T", v, res);
Py_DECREF(res);
return NULL;
}
@@ -883,8 +881,8 @@ PyObject_Bytes(PyObject *v)
return NULL;
if (!PyBytes_Check(result)) {
PyErr_Format(PyExc_TypeError,
- "__bytes__ returned non-bytes (type %.200s)",
- Py_TYPE(result)->tp_name);
+ "%T.__bytes__() must return a bytes, not %T",
+ v, result);
Py_DECREF(result);
return NULL;
}
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 14bc5a4bc49f84..fb33bc747d885b 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -2168,8 +2168,9 @@ type_get_annotations(PyObject *tp, void
*Py_UNUSED(closure))
return NULL;
}
if (!PyDict_Check(annotations)) {
- PyErr_Format(PyExc_TypeError, "__annotate__ returned non-dict
of type '%.100s'",
- Py_TYPE(annotations)->tp_name);
+ PyErr_Format(PyExc_TypeError,
+ "__annotate__() must return a dict, not %T",
+ annotations);
Py_DECREF(annotations);
Py_DECREF(annotate);
Py_DECREF(dict);
@@ -3510,10 +3511,8 @@ mro_check(PyTypeObject *type, PyObject *mro)
for (i = 0; i < n; i++) {
PyObject *obj = PyTuple_GET_ITEM(mro, i);
if (!PyType_Check(obj)) {
- PyErr_Format(
- PyExc_TypeError,
- "mro() returned a non-class ('%.500s')",
- Py_TYPE(obj)->tp_name);
+ PyErr_Format(PyExc_TypeError,
+ "%N.mro() returned a non-class ('%T')", type, obj);
return -1;
}
PyTypeObject *base = (PyTypeObject*)obj;
@@ -3521,8 +3520,8 @@ mro_check(PyTypeObject *type, PyObject *mro)
if (!is_subtype_with_mro(lookup_tp_mro(solid), solid,
solid_base(base))) {
PyErr_Format(
PyExc_TypeError,
- "mro() returned base with unsuitable layout ('%.500s')",
- base->tp_name);
+ "%N.mro() returned base with unsuitable layout ('%N')",
+ type, base);
return -1;
}
}
@@ -10419,9 +10418,8 @@ slot_nb_bool(PyObject *self)
}
else {
PyErr_Format(PyExc_TypeError,
- "__bool__ should return "
- "bool, returned %s",
- Py_TYPE(value)->tp_name);
+ "%T.__bool__() must return a bool, not %T",
+ self, value);
result = -1;
}
Py_DECREF(value);
@@ -10901,7 +10899,8 @@ slot_bf_getbuffer(PyObject *self, Py_buffer *buffer,
int flags)
}
if (!PyMemoryView_Check(ret)) {
PyErr_Format(PyExc_TypeError,
- "__buffer__ returned non-memoryview object");
+ "%T.__buffer__() must return a memoryview, not %T",
+ self, ret);
goto fail;
}
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