Checklist

• I have verified that that issue exists against themaster branch of Django REST framework.
• I have searched for similar issues in both open and closed tickets and cannot find a duplicate.
• This is not a usage question. (Those should be directed to thediscussion group instead.)
• This cannot be dealt with as a third party library. (We prefer new functionality to bein the form of third party libraries where possible.)
• I have reduced the issue to the simplest possible case.
• I have included a failing test as a pull request. (If you are unable to do so we can still accept the issue.)

Steps to reproduce

1. Create aModelSerializer including a field inMeta with a custom name (that isn't on the model).
2. Set the source of the field, inextra_kwargs to a named field within the model.
3. Initialise the Serializer.

Expected behavior

• Creates a Serializer with a field with a custom field name, that has it's source as the specified field on the Model.

Actual behavior

• TypeError: hasattr(): attribute name must be string

Caused by#5138 when accounting for*-sourced fields.

In the case thatsource is specified AND is not'*',
extra_field_kwargs.get('source', '*') != '*' evaluates toTrue, and thussource = True,
leading to theTypeError

Pull Request with test that fails on master, and fix:#5388