Poor error message when many field not set to True when passed a list of instances

[justin107d]

It would be nice if when multiple instances are passed to the serializer that it told you the error was because many=True was not set.

This happened on a ModelSerializer with certain fields excluded shortly after adding a field to the model. The error received referred to the 'missing' field instead of receiving multiple instances. Setting many=True fixed the issue.

I am new to open source and would like to help if I can or if it is appropriate here.

I think adding something similar to the following around line 117-118 of the serializer.py

from django.db.models.query import QuerySet
...
if isinstance(instance, QuerySet) and kwargs.get('many', None) != True:
    raise TypeError('Queryset has multiple instances.  Try submitting only one instance or set many=True')

[tomchristie]

Interesting idea. Could be worth a go yup.
If you're up for submitting a pull request for this we could review and go from there.

[justin107d]

Thanks Tom. I submitted a request with commit id: 63981ec