Submission admin always takes last message

[gabn88]

Unless you take the flow with the right upper button, it seems like a submission always take the last message.

Confirmed steps for reproduction

1. Create two messages belonging to same newsletter, marking one explicitly as last
2. Create new submission from Newsletter admin (not from Message preview)
3. Select the newsletter first added
4. Click 'save and edit'

Expected result

Change form shows last newsletter

Found result

Last added newsletter is selected.

[dokterbob]

Possibly related to #171

[dokterbob]

When saving again, the value is preserved.

[dokterbob]

I still don't know what the cause is, however, the following factors are NOT causing it:

• The custom SubmissionAdminForm.
• The custom change_form.html template.
• The ExtensibleModelAdmin base class.

At this point I am quite clueless as to what might be the cause of this.

[dokterbob]

I've written a regression test but no clue as to the solution. Feel free to pick this one up at any time (but make sure to notify me so we won't accidentily do double work).

[claudep]

I think the culprit is the Sumission.save() method:

if self.pk is None:
            self.message = Message.get_default()

I think the intent was maybe to test if not self.message?

[dokterbob]

@claudep Thanks, that's obviously it.

I guess when I wrote it I wanted to give Submission a sensible default. Hence it should have been if not self.message. However, by now (several years later) it is obvious this should end up as a default value for the form.

Ref: https://docs.djangoproject.com/en/1.9/ref/forms/fields/#initial

[gabn88]

Great that this is resolved so fast! This is why I <3 the Django community!