bpo-38530: Offer suggestions on NameError (GH-25397)
When printing NameError raised by the interpreter, PyErr_Display
will offer suggestions of simmilar variable names in the function that the exception
was raised from:
>>> schwarzschild_black_hole = None
>>> schwarschild_black_hole
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'schwarschild_black_hole' is not defined. Did you mean: schwarzschild_black_hole?diff --git a/Python/ceval.c b/Python/ceval.c
index 53b596b..326930b 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -6319,6 +6319,20 @@ format_exc_check_arg(PyThreadState *tstate, PyObject *exc,
return;
_PyErr_Format(tstate, exc, format_str, obj_str);
+
+ if (exc == PyExc_NameError) {
+ // Include the name in the NameError exceptions to offer suggestions later.
+ _Py_IDENTIFIER(name);
+ PyObject *type, *value, *traceback;
+ PyErr_Fetch(&type, &value, &traceback);
+ PyErr_NormalizeException(&type, &value, &traceback);
+ if (PyErr_GivenExceptionMatches(value, PyExc_NameError)) {
+ // We do not care if this fails because we are going to restore the
+ // NameError anyway.
+ (void)_PyObject_SetAttrId(value, &PyId_name, obj);
+ }
+ PyErr_Restore(type, value, traceback);
+ }
}
static void