Hmm, I think I have a possible solution.

First of all this error message logic could be moved tothe baseget_attribute function. It doesn't seem right that the error handling logic is split between theget_attribute function and the method. One catchesObjectDoesNotExist, the other catchesKeyError andAttributeError. Why not do that all in one place.

Secondly, instead of catchingKeyError andAttributeError exceptions, we could usegetitem andgetattr withdefaults and respond to the default being returned.

Then we can be precise about the issue we're trying to catch, and avoid confusing a exception thrown by code triggered by thegetattr orgetitem / property call, for an error retrieving the key/attr itself.

How does that sound?

I'm having this issue as well, just here to add some more background.

This is somewhat related to#2598, but instead of callables raising an attribute exception this is on property fields. Here's a reproduction:

"""requirements.txt:Django==1.8.2djangorestframework==3.1.3"""fromdjango.confimportsettingsSETTINGS=dict(DATABASES= {},DEBUG=True,TEMPLATE_DEBUG=True,ROOT_URLCONF=None,)settings.configure(**SETTINGS)fromrest_frameworkimportserializersclassExampleSerializer(serializers.Serializer):example_property=serializers.CharField(read_only=True)example_fail_property=serializers.CharField(read_only=True)classExampleInstance(object):@propertydefexample_property(self):return"foobar"@propertydefexample_fail_property(self):raiseAttributeError('property failed')serializer=ExampleSerializer(ExampleInstance())print(serializer.data.items())# ItemsView({'example_property': 'foobar'})

@johtso my first thought is that is feels wrong to have aKeyError orAttributeError.
I'm going to keep this opened to dig a bit more into the issue before I make a final decision.

Just another note as I'm digging further into this: this problem only manifests forread_only=True fields. The exceptions otherwise bubble up properly.

Just got bitten by this again.. any more thoughts on this problem/solution?

just got bit. ouch.

Not obvious how to proceed with this. Thoughts/suggestions welcome.

Just for any googlers arriving here trying to solve a KeyError on get_attribute, it may be due to accessing serializer.data in a situation where validation has already been done. In that case you should be using serializer.validated_data.

http://stackoverflow.com/questions/32236958/keyerror-on-relation-field-in-django-rest

Something to think about later -#5600 could be adapted to fix this.

@chidg: Good point; still appears in 2018.

Was caught by this. Some other package I rely on for a property had a non-obvious breaking change. My serializer tests failed instantly -- just dropped the field fromserializer.data with no warning/error. Spent half a day tracing the source (thought it was something else breaking the dict comparison in my tests).

A warning log at the least would have been immensely helpful.

Just found out about this discussion and the very same thing still happens today. I also created a simple code snippet that illustrates this behavior:

fromrest_frameworkimportserializersclassExampleSerializer(serializers.Serializer):title=serializers.CharField(read_only=True)classExampleObject:@propertydeftitle(self):returnself.fooobj=ExampleObject()serializer=ExampleSerializer()# Doesn't trigger any errorserializer.to_representation(obj)# Triggers an AttributeErrorobj.title