[PATCH 0/2] diffcore-rename with duplicate tree entries can segfault

On Wed, Feb 25, 2015 at 01:50:38PM -0800, Junio C Hamano wrote:

quoted

So to go forward, I'm happy to prepare a patch, but I'd like to know:

  1. Does something like the above look reasonable to you (I'd probably
     refactor it to avoid the bizarre return value semantics from
     locate_rename_dst, though)?

  2. If so, do you want something minimal like what's above, or do you
     mind if I build it on top of a hashmap conversion? I suspect the
     logic may also end up more clear with the hashmap (since inserting
     versus lookup will be more distinct in the callers).

No, I don't mind.  The diff-b-m topic seems to need a lot deeper
rethink than I originally anticipated anyway, and it can wait for a
clean-up to use hashmap to stabilize.

I tried switching to a hashmap, but the diff_score code actually wants
to index into the array using an int. In a hashmap, we'd use a pointer
instead, but that increases the size of "struct diff_score", which is
something that we have to allocate a lot of (src * dst, I think).

So I punted on that and just cleaned up the locate_rename_dst interface
a bit.  Here's the result.

  [1/2]: diffcore-rename: split locate_rename_dst into two functions
  [2/2]: diffcore-rename: avoid processing duplicate destinations

-Peff