Re: "git apply --check" successes but git am says "does not match index"

[Jeff King <peff@peff.net>]

On Sun, Aug 14, 2011 at 09:36:30AM +0000, Zemacsh wrote:

> Before applying a mbox patch, "git apply --check" reports OK. Then, I run 'git 
> am', however, it complains "does not match index". Actually, both working tree 
> and index are clean. what might be the problem?
> 
> If I run "git am --abort" now, and re-turn "git am". To my surprise, everything 
> goes well.

Hmm. I don't think this has anything to do with the "apply --check". But
rather the problem is that "git am" doesn't ever refresh the index. For
example:

  git init repo &&
  cd repo &&
  echo one >file && git add . && git commit -m one &&
  echo two >file && git add . && git commit -m two &&
  git format-patch -1 --stdout >patch &&
  git reset --hard HEAD^ &&
  sleep 1 &&
  touch file &&
  git am patch

This fails with:

  Applying: two
  error: file: does not match index
  Patch failed at 0001 two

Running "git am --abort" resets the index, which freshens it, and then a
further "git am" works:

  $ git am --abort
  $ git am patch
  Applying: two

We should perhaps call "update-index --refresh" at the start to avoid
these sorts of false positives. Probably it should happen whenever we
"git am --continue", as well. But for efficiency reasons, not between
each patch.

I dunno. Do people want to call "git am" in a tight loop, where the
index refresh would be a problem? I would think they should instead feed
a whole mbox in one go.

-Peff