Transparently keep reference of routers in urls generated by routers

[dimitri-justeau]

This PR slightly change the behavior of routers, to ensure that when they create a url pattern (RegexURLPattern or RegexURLResolver), it keeps a reference of the router.

The reason for this is to enhance reflexion possibilities on DRF for third-party libraries (I actually decided to suggest this because working with django-rest-framework-docs, I figured out that the support of Viewsets was complicated because the library focuses on api endpoints, and then cannot automatically discover routers - and thus methods mapping).

Important: The changes made in this PR is completely transparent for DRF users.

What I actually did: I created a subclass of django's RegexURLPattern (DrfRegexURLPattern) and a subclass of django's RegexURLResolver (DrfRegexURLResolver), both adding a router property to their super class, but behaving exactly the same. I also rewrited thedjango.conf.urls.url function to make it instantiate DrfRegexURLPattern and DrfRegexURLResolver, and replaced django's one by this one in the get_urls method of routers.

[dimitri-justeau]

Can you give me a feedback on this proposition? Is it something worth considering?

[tomchristie]

The short answer is: Not terribly keen on the extra complexity, no.
It'd be worth you taking a look at the schema generation and seeing if any of the problems you've cited are addressed there. If not, then what are we getting wrong in the schema generation as a result? If so, can the schema generation approach be used with the third party tools you've mentioned.

[dimitri-justeau]

Ok, thank you, I'll have a look on schema generation!

[tomchristie]

Will close this for now, feel free to come back to it if you've further comments and we can consider re-opening if relevant.