From 9f4e031bd3cb13d5879fe9ad3d889ce861b0babe Mon Sep 17 00:00:00 2001 From: Raphaël Hertzog Date: Wed, 25 Nov 2015 12:54:52 +0100 Subject: Fixed #25761 -- Added __cause__.__traceback__ to reraised exceptions. When Django reraises an exception, it sets the __cause__ attribute even in Python 2, mimicking Python's 3 behavior for "raise Foo from Bar". However, Python 3 also ensures that all exceptions have a __traceback__ attribute and thus the "traceback2" Python 2 module (backport of Python 3's "traceback" module) relies on the fact that whenever you have a __cause__ attribute, the recorded exception also has a __traceback__ attribute. This is breaking testtools which is using traceback2 (see https://github.com/testing-cabal/testtools/issues/162). This commit fixes this inconsistency by ensuring that Django sets the __traceback__ attribute on any exception stored in a __cause__ attribute of a reraised exception. --- docs/ref/exceptions.txt | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'docs/ref') diff --git a/docs/ref/exceptions.txt b/docs/ref/exceptions.txt index f847019c52..7e03c42286 100644 --- a/docs/ref/exceptions.txt +++ b/docs/ref/exceptions.txt @@ -196,7 +196,13 @@ As per :pep:`3134`, a ``__cause__`` attribute is set with the original (underlying) database exception, allowing access to any additional information provided. (Note that this attribute is available under both Python 2 and Python 3, although :pep:`3134` normally only applies -to Python 3.) +to Python 3. To avoid unexpected differences with Python 3, Django will also +ensure that the exception made available via ``__cause__`` has a usable +``__traceback__`` attribute.) + +.. versionchanged:: 1.10 + + The ``__traceback__`` attribute described above was added. .. exception:: models.ProtectedError -- cgit v1.3