Code review comment for lp:~ian-clatworthy/bzr/eol-st-ci-fix

This patch fixes some very bad bugs in content filtering. There are actually 2 separate issues fixed:

1. Branching from a non-content-filtered tree to a content-filtered one would produce an incorrect dirstate because the optimisation to reuse the source dirstate wasn't being disabled

2. Status detection was relying on size matching to determine equivalence when that assumption doesn't hold in the presence of content filtering.

Both code changes are quite straightforward, though the latter one requires fixes in both Python and Pyrex code. Testing all of this is far more complex though. I've added a heap more units tests and I'm comfortable that status on content filtered trees now has pretty good coverage.

I'm yet to add detailed tests for the branch/commit issue, because the monkey-patching approach used to test status isn't at the right level to work for branch. I have tested it manually though and one of the bug reporters (Frits) has confirmed that the code fixes works correctly for him. Given the related code change - switching off an optional optimisation - is very straight forward, I think this patch can land as is for 1.16rc1.

FWIW, my plan is to add those additional tests soon. (Some pending changes to the monkey-patching used here to fix some other bugs will make that easier, but they aren't ready to go, and this really needs to be landed for content filtering to be unbroken for users.)