git-am: Keep index in case of abort with dirty index

git am --abort resets the index unconditionally. But in case a previous
git am exited due to a dirty index it is preferable to keep that index.
Make it so.

Signed-off-by: Michael J Gruber <git@drmicha.warpmail.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-am.sh b/git-am.sh
index 8bcb206..351b4f8 100755 (executable)
--- a/git-am.sh
+++ b/git-am.sh
@@ -230,11 +230,14 @@ then
                ;;
        ,t)
                git rerere clear
-               git read-tree --reset -u HEAD ORIG_HEAD
-               git reset ORIG_HEAD
+               test -f "$dotest/dirtyindex" || {
+                       git read-tree --reset -u HEAD ORIG_HEAD
+                       git reset ORIG_HEAD
+               }
                rm -fr "$dotest"
                exit ;;
        esac
+       rm -f "$dotest/dirtyindex"
 else
        # Make sure we are not given --skip, --resolved, nor --abort
        test "$skip$resolved$abort" = "" ||
@@ -287,7 +290,11 @@ fi
 case "$resolved" in
 '')
        files=$(git diff-index --cached --name-only HEAD --) || exit
-       test "$files" && die "Dirty index: cannot apply patches (dirty: $files)"
+       if test "$files"
+       then
+               : >"$dotest/dirtyindex"
+               die "Dirty index: cannot apply patches (dirty: $files)"
+       fi
 esac
 
 if test "$(cat "$dotest/utf8")" = t