Allow using ExceptionReporter subclass in django.views.debug.technical_500_response

[Carlton Gibson]

#29714 allows using an ExceptionReporter subclass with AdminEmailHandler.

Ideally we'd make the similar available for the 500 debug error view.

​Currently the use of `ExceptionReporter` is hardcoded.

* Move this to a parameter
* Provide an example of using, e.g., functools.partial to configure a subclass when specifying handler500.

Updated for comment:5

• Add ExceptionReporter to the documentation, explaining the relation between the exception reporter class and the filter it uses, and showing a simple override of get_traceback_data().
• Add a DEFAULT_EXCEPTION_REPORTER setting to allow specifying this.

(At that point we could review deprecating DEFAULT_EXCEPTION_REPORTER_FILTER, as was discussed on #25167 — but maybe that's unnecessary. Thoughts?)

[Pavel Lysak]

Hi!

But as i see handler500 and technical_500_response are different things. The first is view which we can set in settings and which runs when DEBUG = False.
The second one runs when DEBUG = True. And it called from response_for_exception and handle_uncaught_exception. So i don't think that we can use functools.partial when providing the handler500 in the URLConf.

Am i wrong?

[Carlton Gibson]

Hi Pavel, thanks for your input.

You're absolutely correct re the handler500 suggestion. That's not sufficient at all. (I'm not sure quite what was in my head thinking about this.)
I've adjusted the description appropriately.

Looking at it, there's no nice way to pass down the exception reporter class so, I agree, a setting will be the easiest way forward.

Your PR looks more or less right, but I think we need to say more in the Custom error reports section of the docs. Specifically we should probably begin stating that the reports are created by the ExceptionReporter class, and that it uses an ExceptionReporterFilter to control the filtering. Then then existing filtering examples are OK — that's the first port of call ‚ before giving an override example for ExceptionReporter...

class CustomExceptionReporter(ExceptionReporter):
    def get_traceback_data(self):
        data = super().get_traceback_data()
        # ... remove/add something here...
        return data

That should be about it. (I'm not sure there's any demand to customise anything else on ExceptionReporter.)

Thanks again, super stuff.

[Pavel Lysak]

HI, thank you for review.

I added some more to the docs. Also considered what you mentioned in PR on github.

Also i thought about deprecating DEFAULT_EXCEPTION_REPORTER_FILTER. I like that idea because it may be confusing to have these similar settings.
I think it would not be a problem to use something like this if we only want to change filtering behavior.

class ExceptionReporter:

    filter_class = SafeExceptionReporterFilter

    def __init__(self, request, exc_type, exc_value, tb, is_email=False):
        self.filter = self.filter_class(self.request)
        ...

class CustomExceptionReporter(ExceptionReporter):

    filter_class = CustomExceptionReporterFilter

This will allow us to get rid of DEFAULT_EXCEPTION_REPORTER_FILTER

[Carlton Gibson <carlton@…>]

In 13e4abf8:

Fixed #30752 -- Allowed using ExceptionReporter subclasses in error reports.

[Mariusz Felisiak <felisiak.mariusz@…>]

In 56071826:

Refs #30752 -- Doc'd error reporting related optional request attributes.