When RelatedModel.__unicode__ fails, InlineModelAdmin are not displayed

[benjaoming]

Example code:

class RelatedModel:
    def __unicode__(self):
        return self.invalid_property

class SomeInline(admin.TabularInline):
    model = RelatedModel

class SomeAdmin(admin.ModelAdmin):
    inlines = [SomeInline]

When RelatedModel.__unicode__ is called, an exception occurs but is silently ignored. The inlines work fine when adding new objects with SomeAdmin, since __unicode__ is not called here. But when editing an object, the inlines simply disappear!

Expected result: An exception should occur.

Similar experiences here: ​http://stackoverflow.com/questions/4102241/django-admin-missing-inlines-for-some-records

[Russell Keith-Magee]

Can't reproduce. With models of

class Author(models.Model):
    name = models.CharField(max_length=100)

    def __unicode__(self):
        return u'Author called %s' % self.name


class Book(models.Model):
    title = models.CharField(max_length=100)
    author = models.ForeignKey(Author)

    def __unicode__(self):
        return u'Book called %s' % self.invalid

and admin registration:

class BookInline(admin.TabularInline):
    model = Book

class AuthorAdmin(admin.ModelAdmin):
    inlines = [BookInline]


admin.site.register(Author, AuthorAdmin)

I get a full page exception, reading

AttributeError at /admin/testapp/author/1/
'Book' object has no attribute 'invalid'

Which is exactly what I'd expect to see.

If you can provide models that cause the error, feel free to reopen.

[anonymous]

Confirmed that I'm unable to produce this. Will reopen if I get the scenario right again.

[Luke Plant]

I had something like this not long ago, but found it depended on the value of DEBUG. With DEBUG==True, everything worked fine, but with DEBUG==False you got silent failure and the inline simply disappeared.

In my case, it was a UnicodeDecodeError or UnicodeEncodeError in the __unicode__ method. I ran out of time debugging in.

[benjaoming]

Yesterday, I also ran out of time trying to debug this on an invalid ascii string ("æøå" instead of u"æøå"). It was fed to a proxy object (ugettext_lazy) inside a template tag, and when the rendering happened, it only failed with DEBUG=False.

Something strange happens in the template compiler, in this case using classy-tags and a template tag from django-cms. Somehow, a DjangoUnicodeDecodeError is lost when DEBUG=True, but replacing that exception (in django.utils.encoding) with a different exception class, and it gets raised.