Merge branch 'pw/sequencer-in-process-commit'

The sequencer infrastructure is shared across "git cherry-pick",
"git rebase -i", etc., and has always spawned "git commit" when it
needs to create a commit.  It has been taught to do so internally,
when able, by reusing the codepath "git commit" itself uses, which
gives performance boost for a few tens of percents in some sample
scenarios.

* pw/sequencer-in-process-commit:
  sequencer: run 'prepare-commit-msg' hook
  t7505: add tests for cherry-pick and rebase -i/-p
  t7505: style fixes
  sequencer: assign only free()able strings to gpg_sign
  sequencer: improve config handling
  t3512/t3513: remove KNOWN_FAILURE_CHERRY_PICK_SEES_EMPTY_COMMIT=1
  sequencer: try to commit without forking 'git commit'
  sequencer: load commit related config
  sequencer: simplify adding Signed-off-by: trailer
  commit: move print_commit_summary() to libgit
  commit: move post-rewrite code to libgit
  Add a function to update HEAD after creating a commit
  commit: move empty message checks to libgit
  t3404: check intermediate squash messages

t/t3404-rebase-interactive.sh

@@ -453,6 +453,10 @@ test_expect_success C_LOCALE_OUTPUT 'squash and fixup generate correct log messa
 		git rebase -i $base &&
 	git cat-file commit HEAD | sed -e 1,/^\$/d > actual-squash-fixup &&
 	test_cmp expect-squash-fixup actual-squash-fixup &&
+	git cat-file commit HEAD@{2} |
+		grep "^# This is a combination of 3 commits\."  &&
+	git cat-file commit HEAD@{3} |
+		grep "^# This is a combination of 2 commits\."  &&
 	git checkout to-be-rebased &&
 	git branch -D squash-fixup
 '
@@ -1336,6 +1340,16 @@ test_expect_success 'editor saves as CR/LF' '
 
 SQ="'"
 test_expect_success 'rebase -i --gpg-sign=<key-id>' '
+	test_when_finished "test_might_fail git rebase --abort" &&
+	set_fake_editor &&
+	FAKE_LINES="edit 1" git rebase -i --gpg-sign="\"S I Gner\"" HEAD^ \
+		>out 2>err &&
+	test_i18ngrep "$SQ-S\"S I Gner\"$SQ" err
+'
+
+test_expect_success 'rebase -i --gpg-sign=<key-id> overrides commit.gpgSign' '
+	test_when_finished "test_might_fail git rebase --abort" &&
+	test_config commit.gpgsign true &&
 	set_fake_editor &&
 	FAKE_LINES="edit 1" git rebase -i --gpg-sign="\"S I Gner\"" HEAD^ \
 		>out 2>err &&

t/t3512-cherry-pick-submodule.sh

@@ -5,7 +5,6 @@ test_description='cherry-pick can handle submodules'
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/lib-submodule-update.sh
 
-KNOWN_FAILURE_CHERRY_PICK_SEES_EMPTY_COMMIT=1
 KNOWN_FAILURE_NOFF_MERGE_DOESNT_CREATE_EMPTY_SUBMODULE_DIR=1
 KNOWN_FAILURE_NOFF_MERGE_ATTEMPTS_TO_MERGE_REMOVED_SUBMODULE_FILES=1
 test_submodule_switch "git cherry-pick"

t/t3513-revert-submodule.sh

@@ -25,7 +25,6 @@ git_revert () {
 	git revert HEAD
 }
 
-KNOWN_FAILURE_CHERRY_PICK_SEES_EMPTY_COMMIT=1
 KNOWN_FAILURE_NOFF_MERGE_DOESNT_CREATE_EMPTY_SUBMODULE_DIR=1
 test_submodule_switch "git_revert"
 

t/t7505-prepare-commit-msg-hook.sh

@@ -4,6 +4,38 @@ test_description='prepare-commit-msg hook'
 
 . ./test-lib.sh
 
+test_expect_success 'set up commits for rebasing' '
+	test_commit root &&
+	test_commit a a a &&
+	test_commit b b b &&
+	git checkout -b rebase-me root &&
+	test_commit rebase-a a aa &&
+	test_commit rebase-b b bb &&
+	for i in $(test_seq 1 13)
+	do
+		test_commit rebase-$i c $i
+	done &&
+	git checkout master &&
+
+	cat >rebase-todo <<-EOF
+	pick $(git rev-parse rebase-a)
+	pick $(git rev-parse rebase-b)
+	fixup $(git rev-parse rebase-1)
+	fixup $(git rev-parse rebase-2)
+	pick $(git rev-parse rebase-3)
+	fixup $(git rev-parse rebase-4)
+	squash $(git rev-parse rebase-5)
+	reword $(git rev-parse rebase-6)
+	squash $(git rev-parse rebase-7)
+	fixup $(git rev-parse rebase-8)
+	fixup $(git rev-parse rebase-9)
+	edit $(git rev-parse rebase-10)
+	squash $(git rev-parse rebase-11)
+	squash $(git rev-parse rebase-12)
+	edit $(git rev-parse rebase-13)
+	EOF
+'
+
 test_expect_success 'with no hook' '
 
 	echo "foo" > file &&
@@ -31,17 +63,41 @@ mkdir -p "$HOOKDIR"
 echo "#!$SHELL_PATH" > "$HOOK"
 cat >> "$HOOK" <<'EOF'
 
-if test "$2" = commit; then
-  source=$(git rev-parse "$3")
+GIT_DIR=$(git rev-parse --git-dir)
+if test -d "$GIT_DIR/rebase-merge"
+then
+	rebasing=1
 else
-  source=${2-default}
+	rebasing=0
 fi
-if test "$GIT_EDITOR" = :; then
-  sed -e "1s/.*/$source (no editor)/" "$1" > msg.tmp
+
+get_last_cmd () {
+	tail -n1 "$GIT_DIR/rebase-merge/done" | {
+		read cmd id _
+		git log --pretty="[$cmd %s]" -n1 $id
+	}
+}
+
+if test "$2" = commit
+then
+	if test $rebasing = 1
+	then
+		source="$3"
+	else
+		source=$(git rev-parse "$3")
+	fi
 else
-  sed -e "1s/.*/$source/" "$1" > msg.tmp
+	source=${2-default}
+fi
+test "$GIT_EDITOR" = : && source="$source (no editor)"
+
+if test $rebasing = 1
+then
+	echo "$source $(get_last_cmd)" >"$1"
+else
+	sed -e "1s/.*/$source/" "$1" >msg.tmp
+	mv msg.tmp "$1"
 fi
-mv msg.tmp "$1"
 exit 0
 EOF
 chmod +x "$HOOK"
@@ -156,6 +212,63 @@ test_expect_success 'with hook and editor (merge)' '
 	test "$(git log -1 --pretty=format:%s)" = "merge"
 '
 
+test_rebase () {
+	expect=$1 &&
+	mode=$2 &&
+	test_expect_$expect C_LOCALE_OUTPUT "with hook (rebase $mode)" '
+		test_when_finished "\
+			git rebase --abort
+			git checkout -f master
+			git branch -D tmp" &&
+		git checkout -b tmp rebase-me &&
+		GIT_SEQUENCE_EDITOR="cp rebase-todo" &&
+		GIT_EDITOR="\"$FAKE_EDITOR\"" &&
+		(
+			export GIT_SEQUENCE_EDITOR GIT_EDITOR &&
+			test_must_fail git rebase $mode b &&
+			echo x >a &&
+			git add a &&
+			test_must_fail git rebase --continue &&
+			echo x >b &&
+			git add b &&
+			git commit &&
+			git rebase --continue &&
+			echo y >a &&
+			git add a &&
+			git commit &&
+			git rebase --continue &&
+			echo y >b &&
+			git add b &&
+			git rebase --continue
+		) &&
+		if test $mode = -p # reword amended after pick
+		then
+			n=18
+		else
+			n=17
+		fi &&
+		git log --pretty=%s -g -n$n HEAD@{1} >actual &&
+		test_cmp "$TEST_DIRECTORY/t7505/expected-rebase$mode" actual
+	'
+}
+
+test_rebase success -i
+test_rebase success -p
+
+test_expect_success 'with hook (cherry-pick)' '
+	test_when_finished "git checkout -f master" &&
+	git checkout -B other b &&
+	git cherry-pick rebase-1 &&
+	test "$(git log -1 --pretty=format:%s)" = "message (no editor)"
+'
+
+test_expect_success 'with hook and editor (cherry-pick)' '
+	test_when_finished "git checkout -f master" &&
+	git checkout -B other b &&
+	git cherry-pick -e rebase-1 &&
+	test "$(git log -1 --pretty=format:%s)" = merge
+'
+
 cat > "$HOOK" <<'EOF'
 #!/bin/sh
 exit 1
@@ -197,4 +310,11 @@ test_expect_success 'with failing hook (merge)' '
 
 '
 
+test_expect_success C_LOCALE_OUTPUT 'with failing hook (cherry-pick)' '
+	test_when_finished "git checkout -f master" &&
+	git checkout -B other b &&
+	test_must_fail git cherry-pick rebase-1 2>actual &&
+	test $(grep -c prepare-commit-msg actual) = 1
+'
+
 test_done

t/t7505/expected-rebase-i

@@ -0,0 +1,17 @@
+message [edit rebase-13]
+message (no editor) [edit rebase-13]
+message [squash rebase-12]
+message (no editor) [squash rebase-11]
+default [edit rebase-10]
+message (no editor) [edit rebase-10]
+message [fixup rebase-9]
+message (no editor) [fixup rebase-8]
+message (no editor) [squash rebase-7]
+message [reword rebase-6]
+message [squash rebase-5]
+message (no editor) [fixup rebase-4]
+message (no editor) [pick rebase-3]
+message (no editor) [fixup rebase-2]
+message (no editor) [fixup rebase-1]
+merge [pick rebase-b]
+message [pick rebase-a]

t/t7505/expected-rebase-p

@@ -0,0 +1,18 @@
+message [edit rebase-13]
+message (no editor) [edit rebase-13]
+message [squash rebase-12]
+message (no editor) [squash rebase-11]
+default [edit rebase-10]
+message (no editor) [edit rebase-10]
+message [fixup rebase-9]
+message (no editor) [fixup rebase-8]
+message (no editor) [squash rebase-7]
+HEAD [reword rebase-6]
+message (no editor) [reword rebase-6]
+message [squash rebase-5]
+message (no editor) [fixup rebase-4]
+message (no editor) [pick rebase-3]
+message (no editor) [fixup rebase-2]
+message (no editor) [fixup rebase-1]
+merge [pick rebase-b]
+message [pick rebase-a]