QuerySet._combine does not combine where clause

[graham@…]

In db/models/query.py, QuerySet, the _combine method does not actually combine the two query sets. Instead if clones the second one and returns that.

To reproduce:

• Create a custom manager for an object that uses the admin interface, and has a search box.

• Make that custom manager change the 'where' clause of it's query set, for example by using the 'extra' method to limit the query via a join.

• List the objects in the admin interface. You will see the limited set, which is correct.

• Use the search box on the list admin page. The results now returned are not limited by your manager, because the 'where' clause gets lost.

[graham@…]

Adding this in QuerySet._combine from line 384 fixes it:

        if self._select: combined._select.update(self._select)
        if self._where: combined._where.extend(self._where)
        if self._params: combined._params.extend(self._params)
        if self._tables: combined._tables.extend(self._tables) 

I can provide a patch if needed.

[Adrian Holovaty]

(In [3019]) Fixed #2038 -- QuerySet._combine now combines where clause. Thanks, graham@…