am --skip: support skipping while on unborn branch

When git am --skip is run, git am will copy HEAD's tree entries to the
index with "git reset HEAD". However, on an unborn branch, HEAD does not
point to a tree, so "git reset HEAD" will fail.

Fix this by treating HEAD as en empty tree when we are on an unborn
branch.

Signed-off-by: Paul Tan <pyokagan@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-am.sh b/git-am.sh
index c5e139f..e0d067c 100755 (executable)
--- a/git-am.sh
+++ b/git-am.sh
@@ -499,9 +499,7 @@ then
                git read-tree --reset -u $head_tree $head_tree &&
                index_tree=$(git write-tree) &&
                git read-tree -m -u $index_tree $head_tree
-               orig_head=$(cat "$GIT_DIR/ORIG_HEAD")
-               git reset HEAD
-               git update-ref ORIG_HEAD $orig_head
+               git read-tree $head_tree
                ;;
        ,t)
                if test -f "$dotest/rebasing"

diff --git a/t/t4151-am-abort.sh b/t/t4151-am-abort.sh
index 2683ffa..2a7c524 100755 (executable)
--- a/t/t4151-am-abort.sh
+++ b/t/t4151-am-abort.sh
@@ -92,4 +92,14 @@ test_expect_success 'am -3 stops on conflict on unborn branch' '
        test 4 = "$(cat otherfile-4)"
 '
 
+test_expect_success 'am -3 --skip clears index on unborn branch' '
+       test_path_is_dir .git/rebase-apply &&
+       echo tmpfile >tmpfile &&
+       git add tmpfile &&
+       git am --skip &&
+       test -z "$(git ls-files)" &&
+       test_path_is_missing otherfile-4 &&
+       test_path_is_missing tmpfile
+'
+
 test_done