Opened 2 months ago

Closed 2 months ago

#29486 closed Bug (needsinfo)

Odd behaviour with ForeignKey to non-integer field since Django 2.0.5 with PostgreSQL

Reported by: Henrik Ossipoff Hansen Owned by: nobody
Component: Migrations Version: 2.0
Severity: Normal Keywords:
Cc: Triage Stage: Unreviewed
Has patch: no Needs documentation: no
Needs tests: no Patch needs improvement: no
Easy pickings: no UI/UX: no


I was upgrading one of our projects from 1.11.x to the newest Django 2.0.x when encountering a rather odd thing - all of our tests were literally failing with seemingly a database error:

django.db.utils.DataError: value "1111222233334444" is out of range for type integer

The field, however, is not an integer field, but rather a char field - so that particular string shouldn't be of any problem - and the fact that it appears to report back being an integer field is rather bizarre.

While I know that this error returned is simply a psycopg2.DataError in disguise, it turns out that this error seem to have been introduced in 2.0.5 specifically - all of our tests passes in 2.0.4.

The slight problem here is that I've been unable to reproduce a minimal working example that can reproduce the error, even though it's really consistent for us.

Our models look something like this (simplified):

class Giftcard(Model):

        (STATUS_CREATED, 'Created'),
        (STATUS_ACTIVATED, 'Activated'),
        (STATUS_SUSPENDED, 'Suspended'),
        (STATUS_EXPIRED, 'Expired'),
        (STATUS_CLOSED, 'Closed'),

    code = models.CharField(max_length=16, primary_key=True)
    status = models.CharField(max_length=20, choices=STATUS_CHOICE, default=STATUS_CREATED, db_index=True)

    def status_change(self, reason, to):
        StatusChangeLog.objects.create(giftcard=self, reason=reason, from_status=self.status, to_status=to)

class StatusChangeLog(Model):
    giftcard = models.ForeignKey('giftcards.Giftcard', related_name='status_logs', on_delete=models.PROTECT)
    reason = models.TextField(blank=True, default='')
    from_status = models.CharField(max_length=20, choices=Giftcard.STATUS_CHOICE)
    to_status = models.CharField(max_length=20, choices=Giftcard.STATUS_CHOICE)

When the Giftcard model is instantiated with a code of "1111222233334444" (as a string), saved, and then the status_change method is called, the above exception occurs.

I've been through some of code that went into 2.0.5, but I'm not well enough into the inner workings of Django know exactly what caused this - I just know that this behaviour wasn't in 1.11.x, and also wasn't in 2.0.4.

Change History (6)

comment:1 Changed 2 months ago by Alexandr Tatarinov

Cannot reproduce at 2.0.5 with PostgreSQL.Try to bisect to find the commit at which tests starts to fail.

comment:2 Changed 2 months ago by Alexandr Tatarinov

Component: UncategorizedDatabase layer (models, ORM)
Type: UncategorizedBug

comment:3 Changed 2 months ago by Henrik Ossipoff Hansen

I've bisected the commit to be d5018abf1c4e3c68f1a825d05eb9035325707e16

I'm not entirely sure why this commit in particular is causing problems though - and I'm a bit puzzled that we're unable to reproduce it with a "clean" model. Could this mean it's related to applying the migration history during our unit tests?

I suppose I could try to get together a working test set tomorrow.

comment:4 Changed 2 months ago by Alexandr Tatarinov

Component: Database layer (models, ORM)Migrations

comment:5 Changed 2 months ago by Tim Graham

Yes, it looks like it's related to migrations and an AlterField operation.

comment:6 Changed 2 months ago by Tim Graham

Resolution: needsinfo
Status: newclosed

Please reopen when you provide a sample project and confirm that Django is at fault.

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