#31672: debug error view shows no traceback if exc.__traceback__ is None for
innermost exception
-------------------------------------+-------------------------------------
Reporter: Chris | Owner: (none)
Jerdonek |
Type: | Status: new
Uncategorized |
Component: Error | Version: 3.0
reporting | Keywords:
Severity: Normal | technical_500_response,traceback,chain
Triage Stage: | Has patch: 0
Unreviewed |
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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Consider this test view which raises an exception:
{{{
#!python
class TestView(View):
def get(self, request, *args, **kwargs):
try:
raise RuntimeError('my error')
except Exception as exc:
# Uncommenting these two lines causes the debug
# server error view not to show **any** portion
# of the traceback.
# new_exc = RuntimeError('my context')
# exc.__context__ = new_exc
raise
}}}
If the indicated lines are uncommented, then the debug error view shows no
traceback info at all.
This is because `django.views.debug.get_traceback_frames()` starts at the
innermost exception in the chain, and then stops adding frames when it
encounters the first exception with `None`-valued
`exc_value.__traceback__`:
https://github.com/django/django/blob/38a21f2d9ed4f556af934498ec6a242f6a20418a/django/views/debug.py#L391
{{{
#!python
exc_value = exceptions.pop()
tb = self.tb if not exceptions else exc_value.__traceback__
while tb is not None:
# Get frame.
...
frames.append({
...
})
# If the traceback for current exception is consumed, try the
# other exception.
if not tb.tb_next and exceptions:
exc_value = exceptions.pop()
tb = exc_value.__traceback__
else:
tb = tb.tb_next
return frames
}}}
It would probably be better and simpler if instead the while loop were
structured to iterate over every exception in the chain no matter what,
and include traceback info only for those exceptions with non-`None`
`__traceback__`. In other words, something like the following:
{{{
#!python
while exceptions:
exc_value = exceptions.pop()
# Returns placeholder frame with no `tb` info if
# `exc_value.__traceback__ is None`.
exc_frames = self.get_traceback_frames(exc_value)
frames.extend(exc_frames)
}}}
This way, the debug error view would always show the complete exception
chain, even if some exceptions in the chain have a `None`-valued traceback
attribute.
--
Ticket URL: <https://code.djangoproject.com/ticket/31672>
Django <https://code.djangoproject.com/>
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