Re: [PATCHv2] git-mv: Keep moved index entries inact

Petr Baudis [off-list ref] writes:

This patch introduces rename_index_entry_at() into the index toolkit,
which will rename an entry while removing any entries the new entry
might render duplicate. This is then used in git mv instead
of all the file queues, resulting in a major simplification
of the code and an inevitable change in git mv -n output format.

A new test has been added to the testsuite to reflect this change.
Also, based on suggestion by Junio about desired symlink behaviour
of git mv, I have added two tests for that; however, I do not have
need or desire to spend time fixing this, so they are expected
to fail for now until someone gets around to fixing that.

I haven't looked into the builtin-mv changes to see how involved that fix
would be yet (and I do not use "mv" and this is somewhat lower priority
for me myself), but I did look at changes to read-cache.c.  I've queued a
fixed up version in 'pu' for now but I am hoping that we can see some
comments from more competent people on the patch and move the review
result to 'next' shortly.

This may be a change in semantics, but after thinking about it a bit more,
I think this can even go into maintenance series.  IOW, it is really a
fix.  Nobody sane should have been relying on the old behaviour that new
contents of dirty paths are staged in the index sometimes, which was
simply just crazy.