revert: introduce --abort to cancel a failed cherry-pick

After running some ill-advised command like "git cherry-pick
HEAD..linux-next", the bewildered novice may want to return to more
familiar territory.  Introduce a "git cherry-pick --abort" command
that rolls back the entire cherry-pick sequence and places the
repository back on solid ground.

Just like "git merge --abort", this internally uses "git reset
--merge", so local changes not involved in the conflict resolution are
preserved.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 96 insertions, 0 deletions

diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index bb67cdcb5..e97397f96 100755
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -2,6 +2,7 @@
 
 test_description='Test cherry-pick continuation features
 
+  + yetanotherpick: rewrites foo to e
   + anotherpick: rewrites foo to d
   + picked: rewrites foo to c
   + unrelatedpick: rewrites unrelated to reallyunrelated
@@ -19,6 +20,12 @@ pristine_detach () {
 	git clean -d -f -f -q -x
 }
 
+test_cmp_rev () {
+	git rev-parse --verify "$1" >expect.rev &&
+	git rev-parse --verify "$2" >actual.rev &&
+	test_cmp expect.rev actual.rev
+}
+
 test_expect_success setup '
 	echo unrelated >unrelated &&
 	git add unrelated &&
@@ -27,6 +34,7 @@ test_expect_success setup '
 	test_commit unrelatedpick unrelated reallyunrelated &&
 	test_commit picked foo c &&
 	test_commit anotherpick foo d &&
+	test_commit yetanotherpick foo e &&
 	git config advice.detachedhead false
 
 '
@@ -75,6 +83,11 @@ test_expect_success '--quit does not complain when no cherry-pick is in progress
 	git cherry-pick --quit
 '
 
+test_expect_success '--abort requires cherry-pick in progress' '
+	pristine_detach initial &&
+	test_must_fail git cherry-pick --abort
+'
+
 test_expect_success '--quit cleans up sequencer state' '
 	pristine_detach initial &&
 	test_must_fail git cherry-pick base..picked &&
@@ -103,6 +116,79 @@ test_expect_success 'cherry-pick --reset (another name for --quit)' '
 	test_cmp expect actual
 '
 
+test_expect_success '--abort to cancel multiple cherry-pick' '
+	pristine_detach initial &&
+	test_must_fail git cherry-pick base..anotherpick &&
+	git cherry-pick --abort &&
+	test_path_is_missing .git/sequencer &&
+	test_cmp_rev initial HEAD &&
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD
+'
+
+test_expect_success '--abort to cancel single cherry-pick' '
+	pristine_detach initial &&
+	test_must_fail git cherry-pick picked &&
+	git cherry-pick --abort &&
+	test_path_is_missing .git/sequencer &&
+	test_cmp_rev initial HEAD &&
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD
+'
+
+test_expect_success 'cherry-pick --abort to cancel multiple revert' '
+	pristine_detach anotherpick &&
+	test_must_fail git revert base..picked &&
+	git cherry-pick --abort &&
+	test_path_is_missing .git/sequencer &&
+	test_cmp_rev anotherpick HEAD &&
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD
+'
+
+test_expect_success 'revert --abort works, too' '
+	pristine_detach anotherpick &&
+	test_must_fail git revert base..picked &&
+	git revert --abort &&
+	test_path_is_missing .git/sequencer &&
+	test_cmp_rev anotherpick HEAD
+'
+
+test_expect_success '--abort to cancel single revert' '
+	pristine_detach anotherpick &&
+	test_must_fail git revert picked &&
+	git revert --abort &&
+	test_path_is_missing .git/sequencer &&
+	test_cmp_rev anotherpick HEAD &&
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD
+'
+
+test_expect_success '--abort keeps unrelated change, easy case' '
+	pristine_detach unrelatedpick &&
+	echo changed >expect &&
+	test_must_fail git cherry-pick picked..yetanotherpick &&
+	echo changed >unrelated &&
+	git cherry-pick --abort &&
+	test_cmp expect unrelated
+'
+
+test_expect_success '--abort refuses to clobber unrelated change, harder case' '
+	pristine_detach initial &&
+	echo changed >expect &&
+	test_must_fail git cherry-pick base..anotherpick &&
+	echo changed >unrelated &&
+	test_must_fail git cherry-pick --abort &&
+	test_cmp expect unrelated &&
+	git rev-list HEAD >log &&
+	test_line_count = 2 log &&
+	test_must_fail git update-index --refresh &&
+
+	git checkout unrelated &&
+	git cherry-pick --abort &&
+	test_cmp_rev initial HEAD
+'
+
 test_expect_success 'cherry-pick cleans up sequencer state when one commit is left' '
 	pristine_detach initial &&
 	test_must_fail git cherry-pick base..picked &&
@@ -127,6 +213,16 @@ test_expect_success 'cherry-pick cleans up sequencer state when one commit is le
 	test_cmp expect actual
 '
 
+test_expect_failure '--abort after last commit in sequence' '
+	pristine_detach initial &&
+	test_must_fail git cherry-pick base..picked &&
+	git cherry-pick --abort &&
+	test_path_is_missing .git/sequencer &&
+	test_cmp_rev initial HEAD &&
+	git update-index --refresh &&
+	git diff-index --exit-code HEAD
+'
+
 test_expect_success 'cherry-pick does not implicitly stomp an existing operation' '
 	pristine_detach initial &&
 	test_must_fail git cherry-pick base..anotherpick &&