From 54485557855d58d9a5027511025d5ab22f721c6d Mon Sep 17 00:00:00 2001 From: James Aylett Date: Tue, 4 Jun 2013 12:31:06 +0100 Subject: [PATCH] Fixed #17601 -- expose underlying db exceptions under py2 Use __cause__ to expose the underlying database exceptions even under python 2. --- django/db/utils.py | 3 +-- docs/ref/exceptions.txt | 8 +++++++- 2 files changed, 8 insertions(+), 3 deletions(-) diff --git a/django/db/utils.py b/django/db/utils.py index 99804ee8fa..bd7e10d24c 100644 --- a/django/db/utils.py +++ b/django/db/utils.py @@ -91,8 +91,7 @@ class DatabaseErrorWrapper(object): except AttributeError: args = (exc_value,) dj_exc_value = dj_exc_type(*args) - if six.PY3: - dj_exc_value.__cause__ = exc_value + dj_exc_value.__cause__ = exc_value # Only set the 'errors_occurred' flag for errors that may make # the connection unusable. if dj_exc_type not in (DataError, IntegrityError): diff --git a/docs/ref/exceptions.txt b/docs/ref/exceptions.txt index 6a5e6f49d5..b15bbea8fa 100644 --- a/docs/ref/exceptions.txt +++ b/docs/ref/exceptions.txt @@ -152,10 +152,16 @@ The Django wrappers for database exceptions behave exactly the same as the underlying database exceptions. See :pep:`249`, the Python Database API Specification v2.0, for further information. +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.) + .. versionchanged:: 1.6 Previous version of Django only wrapped ``DatabaseError`` and - ``IntegrityError``. + ``IntegrityError``, and did not provide ``__cause__``. .. exception:: models.ProtectedError