Merge branch 'pw/advise-rebase-skip'

The mechanism to prevent "git commit" from making an empty commit
or amending during an interrupted cherry-pick was broken during the
rewrite of "git rebase" in C, which has been corrected.

* pw/advise-rebase-skip:
  commit: give correct advice for empty commit during a rebase
  commit: encapsulate determine_whence() for sequencer
  commit: use enum value for multiple cherry-picks
  sequencer: write CHERRY_PICK_HEAD for reword and edit
  cherry-pick: check commit error messages
  cherry-pick: add test for `--skip` advice in `git commit`
  t3404: use test_cmp_rev

4 files changed, 149 insertions, 20 deletions

diff --git a/t/t3403-rebase-skip.sh b/t/t3403-rebase-skip.sh
index ee8a8dba52..a927774910 100755
--- a/t/t3403-rebase-skip.sh
+++ b/t/t3403-rebase-skip.sh
@@ -29,6 +29,13 @@ test_expect_success setup '
 	test_tick &&
 	git commit -m reverted-goodbye &&
 	git tag reverted-goodbye &&
+	git checkout goodbye &&
+	test_tick &&
+	GIT_AUTHOR_NAME="Another Author" \
+		GIT_AUTHOR_EMAIL="another.author@example.com" \
+		git commit --amend --no-edit -m amended-goodbye &&
+	test_tick &&
+	git tag amended-goodbye &&
 
 	git checkout -f skip-reference &&
 	echo moo > hello &&
@@ -85,6 +92,78 @@ test_expect_success 'moved back to branch correctly' '
 
 test_debug 'gitk --all & sleep 1'
 
+test_expect_success 'correct advice upon picking empty commit' '
+	test_when_finished "git rebase --abort" &&
+	test_must_fail git rebase -i --onto goodbye \
+		amended-goodbye^ amended-goodbye 2>err &&
+	test_i18ngrep "previous cherry-pick is now empty" err &&
+	test_i18ngrep "git rebase --skip" err &&
+	test_must_fail git commit &&
+	test_i18ngrep "git rebase --skip" err
+'
+
+test_expect_success 'correct authorship when committing empty pick' '
+	test_when_finished "git rebase --abort" &&
+	test_must_fail git rebase -i --onto goodbye \
+		amended-goodbye^ amended-goodbye &&
+	git commit --allow-empty &&
+	git log --pretty=format:"%an <%ae>%n%ad%B" -1 amended-goodbye >expect &&
+	git log --pretty=format:"%an <%ae>%n%ad%B" -1 HEAD >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'correct advice upon rewording empty commit' '
+	test_when_finished "git rebase --abort" &&
+	(
+		set_fake_editor &&
+		test_must_fail env FAKE_LINES="reword 1" git rebase -i \
+			--onto goodbye amended-goodbye^ amended-goodbye 2>err
+	) &&
+	test_i18ngrep "previous cherry-pick is now empty" err &&
+	test_i18ngrep "git rebase --skip" err &&
+	test_must_fail git commit &&
+	test_i18ngrep "git rebase --skip" err
+'
+
+test_expect_success 'correct advice upon editing empty commit' '
+	test_when_finished "git rebase --abort" &&
+	(
+		set_fake_editor &&
+		test_must_fail env FAKE_LINES="edit 1" git rebase -i \
+			--onto goodbye amended-goodbye^ amended-goodbye 2>err
+	) &&
+	test_i18ngrep "previous cherry-pick is now empty" err &&
+	test_i18ngrep "git rebase --skip" err &&
+	test_must_fail git commit &&
+	test_i18ngrep "git rebase --skip" err
+'
+
+test_expect_success 'correct advice upon cherry-picking an empty commit during a rebase' '
+	test_when_finished "git rebase --abort" &&
+	(
+		set_fake_editor &&
+		test_must_fail env FAKE_LINES="1 exec_git_cherry-pick_amended-goodbye" \
+			git rebase -i goodbye^ goodbye 2>err
+	) &&
+	test_i18ngrep "previous cherry-pick is now empty" err &&
+	test_i18ngrep "git cherry-pick --skip" err &&
+	test_must_fail git commit 2>err &&
+	test_i18ngrep "git cherry-pick --skip" err
+'
+
+test_expect_success 'correct advice upon multi cherry-pick picking an empty commit during a rebase' '
+	test_when_finished "git rebase --abort" &&
+	(
+		set_fake_editor &&
+		test_must_fail env FAKE_LINES="1 exec_git_cherry-pick_goodbye_amended-goodbye" \
+			git rebase -i goodbye^^ goodbye 2>err
+	) &&
+	test_i18ngrep "previous cherry-pick is now empty" err &&
+	test_i18ngrep "git cherry-pick --skip" err &&
+	test_must_fail git commit 2>err &&
+	test_i18ngrep "git cherry-pick --skip" err
+'
+
 test_expect_success 'fixup that empties commit fails' '
 	test_when_finished "git rebase --abort" &&
 	(
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index c5ce3ab760..4a7d21f898 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -187,7 +187,7 @@ test_expect_success 'no changes are a nop' '
 	git checkout branch2 &&
 	git rebase -i F &&
 	test "$(git symbolic-ref -q HEAD)" = "refs/heads/branch2" &&
-	test $(git rev-parse I) = $(git rev-parse HEAD)
+	test_cmp_rev I HEAD
 '
 
 test_expect_success 'test the [branch] option' '
@@ -196,16 +196,16 @@ test_expect_success 'test the [branch] option' '
 	git commit -m "stop here" &&
 	git rebase -i F branch2 &&
 	test "$(git symbolic-ref -q HEAD)" = "refs/heads/branch2" &&
-	test $(git rev-parse I) = $(git rev-parse branch2) &&
-	test $(git rev-parse I) = $(git rev-parse HEAD)
+	test_cmp_rev I branch2 &&
+	test_cmp_rev I HEAD
 '
 
 test_expect_success 'test --onto <branch>' '
 	git checkout -b test-onto branch2 &&
 	git rebase -i --onto branch1 F &&
 	test "$(git symbolic-ref -q HEAD)" = "refs/heads/test-onto" &&
-	test $(git rev-parse HEAD^) = $(git rev-parse branch1) &&
-	test $(git rev-parse I) = $(git rev-parse branch2)
+	test_cmp_rev HEAD^ branch1 &&
+	test_cmp_rev I branch2
 '
 
 test_expect_success 'rebase on top of a non-conflicting commit' '
@@ -214,12 +214,12 @@ test_expect_success 'rebase on top of a non-conflicting commit' '
 	git rebase -i branch2 &&
 	test file6 = $(git diff --name-only original-branch1) &&
 	test "$(git symbolic-ref -q HEAD)" = "refs/heads/branch1" &&
-	test $(git rev-parse I) = $(git rev-parse branch2) &&
-	test $(git rev-parse I) = $(git rev-parse HEAD~2)
+	test_cmp_rev I branch2 &&
+	test_cmp_rev I HEAD~2
 '
 
 test_expect_success 'reflog for the branch shows state before rebase' '
-	test $(git rev-parse branch1@{1}) = $(git rev-parse original-branch1)
+	test_cmp_rev branch1@{1} original-branch1
 '
 
 test_expect_success 'reflog for the branch shows correct finish message' '
@@ -279,7 +279,7 @@ test_expect_success 'show conflicted patch' '
 
 test_expect_success 'abort' '
 	git rebase --abort &&
-	test $(git rev-parse new-branch1) = $(git rev-parse HEAD) &&
+	test_cmp_rev new-branch1 HEAD &&
 	test "$(git symbolic-ref -q HEAD)" = "refs/heads/branch1" &&
 	test_path_is_missing .git/rebase-merge
 '
@@ -322,7 +322,7 @@ test_expect_success 'retain authorship w/ conflicts' '
 	echo resolved >conflict &&
 	git add conflict &&
 	git rebase --continue &&
-	test $(git rev-parse conflict-a^0) = $(git rev-parse HEAD^) &&
+	test_cmp_rev conflict-a^0 HEAD^ &&
 	git show >out &&
 	grep AttributeMe out
 '
@@ -339,7 +339,7 @@ test_expect_success 'squash' '
 			git rebase -i --onto master HEAD~2
 	) &&
 	test B = $(cat file7) &&
-	test $(git rev-parse HEAD^) = $(git rev-parse master)
+	test_cmp_rev HEAD^ master
 '
 
 test_expect_success 'retain authorship when squashing' '
@@ -398,9 +398,9 @@ test_expect_success REBASE_P 'preserve merges with -p' '
 	git update-index --refresh &&
 	git diff-files --quiet &&
 	git diff-index --quiet --cached HEAD -- &&
-	test $(git rev-parse HEAD~6) = $(git rev-parse branch1) &&
-	test $(git rev-parse HEAD~4^2) = $(git rev-parse to-be-preserved) &&
-	test $(git rev-parse HEAD^^2^) = $(git rev-parse HEAD^^^) &&
+	test_cmp_rev HEAD~6 branch1 &&
+	test_cmp_rev HEAD~4^2 to-be-preserved &&
+	test_cmp_rev HEAD^^2^ HEAD^^^ &&
 	test $(git show HEAD~5:file1) = B &&
 	test $(git show HEAD~3:file1) = C &&
 	test $(git show HEAD:file1) = E &&
@@ -432,7 +432,7 @@ test_expect_success '--continue tries to commit' '
 		git add file1 &&
 		FAKE_COMMIT_MESSAGE="chouette!" git rebase --continue
 	) &&
-	test $(git rev-parse HEAD^) = $(git rev-parse new-branch1) &&
+	test_cmp_rev HEAD^ new-branch1 &&
 	git show HEAD | grep chouette
 '
 
@@ -739,7 +739,7 @@ test_expect_success 'do "noop" when there is nothing to cherry-pick' '
 		--author="Somebody else <somebody@else.com>" &&
 	test $(git rev-parse branch3) != $(git rev-parse branch4) &&
 	git rebase -i branch3 &&
-	test $(git rev-parse branch3) = $(git rev-parse branch4)
+	test_cmp_rev branch3 branch4
 
 '
 
@@ -798,7 +798,7 @@ test_expect_success 'rebase -i continue with unstaged submodule' '
 	test_must_fail git rebase -i submodule-base &&
 	git reset &&
 	git rebase --continue &&
-	test $(git rev-parse submodule-base) = $(git rev-parse HEAD)
+	test_cmp_rev submodule-base HEAD
 '
 
 test_expect_success 'avoid unnecessary reset' '
@@ -821,7 +821,7 @@ test_expect_success 'reword' '
 			git rebase -i A &&
 		git show HEAD | grep "E changed" &&
 		test $(git rev-parse master) != $(git rev-parse HEAD) &&
-		test $(git rev-parse master^) = $(git rev-parse HEAD^) &&
+		test_cmp_rev master^ HEAD^ &&
 		FAKE_LINES="1 2 reword 3 4" FAKE_COMMIT_MESSAGE="D changed" \
 			git rebase -i A &&
 		git show HEAD^ | grep "D changed" &&
@@ -885,7 +885,7 @@ test_expect_success 'always cherry-pick with --no-ff' '
 		git diff HEAD~$p original-no-ff-branch~$p > out &&
 		test_must_be_empty out
 	done &&
-	test $(git rev-parse HEAD~3) = $(git rev-parse original-no-ff-branch~3) &&
+	test_cmp_rev HEAD~3 original-no-ff-branch~3 &&
 	git diff HEAD~3 original-no-ff-branch~3 > out &&
 	test_must_be_empty out
 '
@@ -1734,6 +1734,32 @@ test_expect_success 'post-commit hook is called' '
 	test_cmp expect actual
 '
 
+test_expect_success 'correct error message for partial commit after empty pick' '
+	test_when_finished "git rebase --abort" &&
+	(
+		set_fake_editor &&
+		FAKE_LINES="2 1 1" &&
+		export FAKE_LINES &&
+		test_must_fail git rebase -i A D
+	) &&
+	echo x >file1 &&
+	test_must_fail git commit file1 2>err &&
+	test_i18ngrep "cannot do a partial commit during a rebase." err
+'
+
+test_expect_success 'correct error message for commit --amend after empty pick' '
+	test_when_finished "git rebase --abort" &&
+	(
+		set_fake_editor &&
+		FAKE_LINES="1 1" &&
+		export FAKE_LINES &&
+		test_must_fail git rebase -i A D
+	) &&
+	echo x>file1 &&
+	test_must_fail git commit -a --amend 2>err &&
+	test_i18ngrep "middle of a rebase -- cannot amend." err
+'
+
 # This must be the last test in this file
 test_expect_success '$EDITOR and friends are unchanged' '
 	test_editor_unchanged
diff --git a/t/t3507-cherry-pick-conflict.sh b/t/t3507-cherry-pick-conflict.sh
index 9bd482ce3b..752bc43487 100755
--- a/t/t3507-cherry-pick-conflict.sh
+++ b/t/t3507-cherry-pick-conflict.sh
@@ -161,6 +161,29 @@ test_expect_success 'successful commit clears CHERRY_PICK_HEAD' '
 
 	test_must_fail git rev-parse --verify CHERRY_PICK_HEAD
 '
+
+test_expect_success 'partial commit of cherry-pick fails' '
+	pristine_detach initial &&
+
+	test_must_fail git cherry-pick picked &&
+	echo resolved >foo &&
+	git add foo &&
+	test_must_fail git commit foo 2>err &&
+
+	test_i18ngrep "cannot do a partial commit during a cherry-pick." err
+'
+
+test_expect_success 'commit --amend of cherry-pick fails' '
+	pristine_detach initial &&
+
+	test_must_fail git cherry-pick picked &&
+	echo resolved >foo &&
+	git add foo &&
+	test_must_fail git commit --amend 2>err &&
+
+	test_i18ngrep "in the middle of a cherry-pick -- cannot amend." err
+'
+
 test_expect_success 'successful final commit clears cherry-pick state' '
 	pristine_detach initial &&
 
diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
index 793bcc7fe3..5b94fdaa67 100755
--- a/t/t3510-cherry-pick-sequence.sh
+++ b/t/t3510-cherry-pick-sequence.sh
@@ -123,7 +123,8 @@ test_expect_success 'revert --skip to skip commit' '
 test_expect_success 'skip "empty" commit' '
 	pristine_detach picked &&
 	test_commit dummy foo d &&
-	test_must_fail git cherry-pick anotherpick &&
+	test_must_fail git cherry-pick anotherpick 2>err &&
+	test_i18ngrep "git cherry-pick --skip" err &&
 	git cherry-pick --skip &&
 	test_cmp_rev dummy HEAD
 '