Database on commit error logging fails for partials

[Krishnaprasad MG]

The on commit handler here: ​https://github.com/django/django/blob/main/django/db/backends/base/base.py#L763 accepts both callback functions and partials but the error logging has a bug which expects property __qualname__ on the callback method but this doesn't work with partials.

A fix is implemented here: ​https://github.com/django/django/pull/19609

[Simon Charette]

There is effectively a bug here as not all callable will have a __qualname__. Maybe we could simply name = getattr(func, "__qualname__", func) instead?

[Krishnaprasad MG]

This also can be done, the current fix effectively prints the wrapped function name in case of partial, but yes may be this is fine (copied from the tests)

def robust_callback():
raise ForcedError("robust callback")

robust_callback_partial = partial(robust_callback)

>>> getattr(robust_callback_partial, "__qualname__", robust_callback_partial)
functools.partial(<function robust_callback at 0x101287600>)
>>> getattr(robust_callback, "__qualname__", robust_callback)
'robust_callback'

I could update the PR

[Krishnaprasad MG]

One more possible improvement would be to replace the f-string with %s placeholder in log messages if that makes sense

logger.exception(f"Error calling {name} in on_commit() (%s).", e) to logger.exception("Error calling %s in on_commit() (%s).", name, e)

because this helps log collecting systems like Sentry to effectively aggregate log messages without creating separate log messages. Also mentioned in google style guide: ​https://google.github.io/styleguide/pyguide.html#3101-logging

[Krishnaprasad MG]

I have updated the PR. The logging improvements (switching to %s placeholders) are now addressed. Tests are passing on the PR.

[Jacob Walls]

Very close -- just asking to evaluate the feasibility of a third test.

[Jacob Walls <jacobtylerwalls@…>]

In 7a2f35b:

Fixed #36487 -- Fixed logger error message with partial callbacks.