Re: Fix recent 'unpack_trees()'-related changes breaking 'git stash'

[Junio C Hamano <gitster@pobox.com>]

Linus Torvalds <torvalds@linux-foundation.org> writes:

> Damn, this series has had more subtle issues than I ever expected.
>
> 'git stash' creates its saved working tree object with:
>
>         # state of the working tree
>         w_tree=$( (
>                 rm -f "$TMP-index" &&
>                 cp -p ${GIT_INDEX_FILE-"$GIT_DIR/index"} "$TMP-index" &&
>                 GIT_INDEX_FILE="$TMP-index" &&
>                 export GIT_INDEX_FILE &&
>                 git read-tree -m $i_tree &&
>                 git add -u &&
>                 git write-tree &&
>                 rm -f "$TMP-index"
>         ) ) ||
>                 die "Cannot save the current worktree state"
>
> which creates a new index file with the updates, and writes the tree from 
> that.

It would be slightly simpler to write the above sequence like this:

	w_tree=$( (
		rm -f "$TMP-index" &&
                git read-tree --index-output="$TMP-index" -m $i_tree &&
                GIT_INDEX_FILE="$TMP-index" &&
                export GIT_INDEX_FILE &&
                git add -u &&
                git write-tree &&
                rm -f "$TMP-index"
	) )

I think your fix would apply equally well if we rewrite stash to work like
this.