serializing foreignkeys assumes value is serializable

[Alex Burgel]

in django.core.serializers.python, handle_fk_field and handle_m2m_field assume that the foreignkey value requires no conversion, i.e. value_to_string is not called. handle_fk_field sometimes does not even convert the foreignkey value to a string (line 58).

if you're using custom fields whose values are not serializable, then you're given no opportunity for conversion, and in the case of json, if that value isn't a native json type, then you get an exception.

the way to work around this is to write your own serializer or to use natural keys, but given that value_to_string exists, it should be used.

[Claude Paroz]

A test case would be nice, or at least an example model wich would surely fail to serialize properly.

[Alex Burgel]

added a failing test case. i'm working on a fix as well.

[Alex Burgel]

added a patch with a test case and a fix for both python and xml serializers.

i didn't tackle the m2m case, but from the code it looks like you can only use a pk or a natural key, so maybe its not an issue.

[Alex Burgel]

btw, the patch is off the git mirror of the 1.3.X branch. let me know if i should create it off something different.

[Claude Paroz]

Yes, please provide the patch against master.

[Alex Burgel]

ok, patched against master.

[Claude Paroz]

Apparently, #24320 fixed this issue in 5c995dcfc251b55284e1ef16545acd2acad6be04.