Issue #22836: Keep exception reports sensible despite errors

This commit is contained in:
Martin Panter 2016-02-28 03:16:11 +00:00
parent 738f88f688
commit 3263f6874a
5 changed files with 92 additions and 9 deletions

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@ -74,8 +74,8 @@ Printing and clearing
:meth:`__del__` method.
The function is called with a single argument *obj* that identifies the context
in which the unraisable exception occurred. The repr of *obj* will be printed in
the warning message.
in which the unraisable exception occurred. If possible,
the repr of *obj* will be printed in the warning message.
Raising exceptions

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@ -7,7 +7,7 @@ import pickle
import weakref
import errno
from test.support import (TESTFN, captured_output, check_impl_detail,
from test.support import (TESTFN, captured_stderr, check_impl_detail,
check_warnings, cpython_only, gc_collect, run_unittest,
no_tracing, unlink, import_module)
@ -20,6 +20,10 @@ class SlottedNaiveException(Exception):
def __init__(self, x):
self.x = x
class BrokenStrException(Exception):
def __str__(self):
raise Exception("str() is broken")
# XXX This is not really enough, each *operation* should be tested!
class ExceptionTests(unittest.TestCase):
@ -882,7 +886,7 @@ class ExceptionTests(unittest.TestCase):
class MyException(Exception, metaclass=Meta):
pass
with captured_output("stderr") as stderr:
with captured_stderr() as stderr:
try:
raise KeyError()
except MyException as e:
@ -1011,6 +1015,66 @@ class ExceptionTests(unittest.TestCase):
os.listdir(__file__)
self.assertEqual(cm.exception.errno, errno.ENOTDIR, cm.exception)
def test_unraisable(self):
# Issue #22836: PyErr_WriteUnraisable() should give sensible reports
class BrokenDel:
def __del__(self):
exc = ValueError("del is broken")
# The following line is included in the traceback report:
raise exc
class BrokenRepr(BrokenDel):
def __repr__(self):
raise AttributeError("repr() is broken")
class BrokenExceptionDel:
def __del__(self):
exc = BrokenStrException()
# The following line is included in the traceback report:
raise exc
for test_class in (BrokenDel, BrokenRepr, BrokenExceptionDel):
with self.subTest(test_class):
obj = test_class()
with captured_stderr() as stderr:
del obj
report = stderr.getvalue()
self.assertIn("Exception ignored", report)
if test_class is BrokenRepr:
self.assertIn("<object repr() failed>", report)
else:
self.assertIn(test_class.__del__.__qualname__, report)
self.assertIn("test_exceptions.py", report)
self.assertIn("raise exc", report)
if test_class is BrokenExceptionDel:
self.assertIn("BrokenStrException", report)
self.assertIn("<exception str() failed>", report)
else:
self.assertIn("ValueError", report)
self.assertIn("del is broken", report)
self.assertTrue(report.endswith("\n"))
def test_unhandled(self):
# Check for sensible reporting of unhandled exceptions
for exc_type in (ValueError, BrokenStrException):
with self.subTest(exc_type):
try:
exc = exc_type("test message")
# The following line is included in the traceback report:
raise exc
except exc_type:
with captured_stderr() as stderr:
sys.__excepthook__(*sys.exc_info())
report = stderr.getvalue()
self.assertIn("test_exceptions.py", report)
self.assertIn("raise exc", report)
self.assertIn(exc_type.__name__, report)
if exc_type is BrokenStrException:
self.assertIn("<exception str() failed>", report)
else:
self.assertIn("test message", report)
self.assertTrue(report.endswith("\n"))
class ImportErrorTests(unittest.TestCase):

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@ -10,6 +10,11 @@ Release date: tba
Core and Builtins
-----------------
- Issue #22836: Ensure exception reports from PyErr_Display() and
PyErr_WriteUnraisable() are sensible even when formatting them produces
secondary errors. This affects the reports produced by
sys.__excepthook__() and when __del__() raises an exception.
- Issue #26302: Correct behavior to reject comma as a legal character for
cookie names.

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@ -900,8 +900,12 @@ PyErr_WriteUnraisable(PyObject *obj)
if (obj) {
if (PyFile_WriteString("Exception ignored in: ", f) < 0)
goto done;
if (PyFile_WriteObject(obj, f, 0) < 0)
goto done;
if (PyFile_WriteObject(obj, f, 0) < 0) {
PyErr_Clear();
if (PyFile_WriteString("<object repr() failed>", f) < 0) {
goto done;
}
}
if (PyFile_WriteString("\n", f) < 0)
goto done;
}
@ -946,8 +950,12 @@ PyErr_WriteUnraisable(PyObject *obj)
if (v && v != Py_None) {
if (PyFile_WriteString(": ", f) < 0)
goto done;
if (PyFile_WriteObject(v, f, Py_PRINT_RAW) < 0)
goto done;
if (PyFile_WriteObject(v, f, Py_PRINT_RAW) < 0) {
PyErr_Clear();
if (PyFile_WriteString("<exception str() failed>", f) < 0) {
goto done;
}
}
}
if (PyFile_WriteString("\n", f) < 0)
goto done;

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@ -766,8 +766,11 @@ print_exception(PyObject *f, PyObject *value)
/* only print colon if the str() of the
object is not the empty string
*/
if (s == NULL)
if (s == NULL) {
PyErr_Clear();
err = -1;
PyFile_WriteString(": <exception str() failed>", f);
}
else if (!PyUnicode_Check(s) ||
PyUnicode_GetLength(s) != 0)
err = PyFile_WriteString(": ", f);
@ -776,6 +779,9 @@ print_exception(PyObject *f, PyObject *value)
Py_XDECREF(s);
}
/* try to write a newline in any case */
if (err < 0) {
PyErr_Clear();
}
err += PyFile_WriteString("\n", f);
Py_XDECREF(tb);
Py_DECREF(value);