diff --git a/Lib/test/test_warnings.py b/Lib/test/test_warnings.py index 4bcc210f989..292c018ca22 100644 --- a/Lib/test/test_warnings.py +++ b/Lib/test/test_warnings.py @@ -338,6 +338,20 @@ class WarnTests(unittest.TestCase): self.module.warn_explicit, None, Warning, None, 1, registry=42) + def test_bad_str(self): + # issue 6415 + # Warnings instance with a bad format string for __str__ should not + # trigger a bus error. + class BadStrWarning(Warning): + """Warning with a bad format string for __str__.""" + def __str__(self): + return ("A bad formatted string %(err)" % + {"err" : "there is no %(err)s"}) + + with self.assertRaises(ValueError): + self.module.warn(BadStrWarning()) + + class CWarnTests(BaseTest, WarnTests): module = c_warnings diff --git a/Misc/NEWS b/Misc/NEWS index 0009115dab2..2f9c12a4ec8 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -34,6 +34,8 @@ C-API Library ------- +- Issue #6415: Fixed warnings.warn sagfault on bad formatted string. + - Issue #6358: The exit status of a command started with os.popen() was reported differently than it did with python 2.x. diff --git a/Python/_warnings.c b/Python/_warnings.c index da52e357c3e..ef7f373bddc 100644 --- a/Python/_warnings.c +++ b/Python/_warnings.c @@ -320,6 +320,8 @@ warn_explicit(PyObject *category, PyObject *message, } if (rc == 1) { text = PyObject_Str(message); + if (text == NULL) + goto cleanup; category = (PyObject*)message->ob_type; } else {