Unlike moving a patch to the index, applying or reverting a patch didn't
auto-stash, which means that applying a patch when there's a modified (but
unstaged) file in the working tree would error out with the message "error:
file1: does not match index", regardless of whether those modifications conflict
with the patch or not.
To fix this, we *could* add auto-stashing like we do for the "move patch to
index" command. However, in this case we rather simply stage the affected files
(after asking for confirmation). This has a few advantages:
- it only changes the staging state of those files that are contained in the
patch (whereas auto-stashing always changes all files to unstaged)
- it doesn't unnecessarily show a confirmation if none of the modified files are
affected by the patch
- if the patch conflicts with the modified files, the conflicts were "backwards"
("ours" was the patch, "theirs" the modified file); it is more logical if "ours"
is the current state of the file, and "theirs" is the patch.
It's a little unfortunate that the behavior isn't exactly the same as for "move
patch to index", but for that one we do need the auto-stash because of the
rebase that runs behind the scenes.
3df894ec92