[PATCH 0/2] merge-one-file and GIT_WORK_TREE

[Jeff King <peff@peff.net>]

[argh, resend, actually remembering to cc the list this time]

At GitHub, we're using read-tree, merge-index, and merge-one-file to do
trivial content-level merges from bare repositories (without having to
check out the entire repository contents each time).

However, we noticed a bug in git-merge-one-file when used with
GIT_WORK_TREE; it can silently create bogus results that ignore the
"theirs" side of files needing content-level merging.

The problem is that merge-one-file simply assumes it is in the root of
the working tree without any checking.  The only two places we use
merge-one-file in git itself are in the octopus and resolve strategies.
I think normal use is fine, because "git merge" will have changed to the
toplevel of the worktree already.

So I doubt anybody else is being affected by this. But we do expose the
commands for general use, with no disclaimer or check on the working
tree status or location. And the resulting bogus merge is a nasty
surprise.

  [1/2]: add tests for merge-index / merge-one-file
  [2/2]: merge-one-file: fix broken merges with GIT_WORK_TREE

-Peff