Merge branch 'js/sequencer-and-root-commits'

The implementation of "git rebase -i --root" has been updated to use
the sequencer machinery more.

* js/sequencer-and-root-commits:
  rebase --rebase-merges: root commits can be cousins, too
  rebase --rebase-merges: a "merge" into a new root is a fast-forward
  sequencer: allow introducing new root commits
  rebase -i --root: let the sequencer handle even the initial part
  sequencer: learn about the special "fake root commit" handling
  sequencer: extract helper to update active_cache_tree

3 files changed, 88 insertions, 9 deletions

diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 59c766540e..c65826ddac 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -1204,10 +1204,6 @@ test_expect_success 'drop' '
 	test A = $(git cat-file commit HEAD^^ | sed -ne \$p)
 '
 
-cat >expect <<EOF
-Successfully rebased and updated refs/heads/missing-commit.
-EOF
-
 test_expect_success 'rebase -i respects rebase.missingCommitsCheck = ignore' '
 	test_config rebase.missingCommitsCheck ignore &&
 	rebase_setup_and_clean missing-commit &&
@@ -1215,7 +1211,9 @@ test_expect_success 'rebase -i respects rebase.missingCommitsCheck = ignore' '
 	FAKE_LINES="1 2 3 4" \
 		git rebase -i --root 2>actual &&
 	test D = $(git cat-file commit HEAD | sed -ne \$p) &&
-	test_i18ncmp expect actual
+	test_i18ngrep \
+		"Successfully rebased and updated refs/heads/missing-commit" \
+		actual
 '
 
 cat >expect <<EOF
@@ -1227,15 +1225,24 @@ To avoid this message, use "drop" to explicitly remove a commit.
 Use 'git config rebase.missingCommitsCheck' to change the level of warnings.
 The possible behaviours are: ignore, warn, error.
 
+Rebasing (1/4)
+Rebasing (2/4)
+Rebasing (3/4)
+Rebasing (4/4)
 Successfully rebased and updated refs/heads/missing-commit.
 EOF
 
+cr_to_nl () {
+	tr '\015' '\012'
+}
+
 test_expect_success 'rebase -i respects rebase.missingCommitsCheck = warn' '
 	test_config rebase.missingCommitsCheck warn &&
 	rebase_setup_and_clean missing-commit &&
 	set_fake_editor &&
 	FAKE_LINES="1 2 3 4" \
-		git rebase -i --root 2>actual &&
+		git rebase -i --root 2>actual.2 &&
+	cr_to_nl <actual.2 >actual &&
 	test_i18ncmp expect actual &&
 	test D = $(git cat-file commit HEAD | sed -ne \$p)
 '
diff --git a/t/t3421-rebase-topology-linear.sh b/t/t3421-rebase-topology-linear.sh
index e7438ad06a..99b2aac921 100755
--- a/t/t3421-rebase-topology-linear.sh
+++ b/t/t3421-rebase-topology-linear.sh
@@ -328,9 +328,9 @@ test_run_rebase () {
 		test_cmp_rev c HEAD
 	"
 }
-test_run_rebase failure ''
-test_run_rebase failure -m
-test_run_rebase failure -i
+test_run_rebase success ''
+test_run_rebase success -m
+test_run_rebase success -i
 test_run_rebase failure -p
 
 test_run_rebase () {
diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
index 3d4dfdf7be..ce6de6f491 100755
--- a/t/t3430-rebase-merges.sh
+++ b/t/t3430-rebase-merges.sh
@@ -241,4 +241,76 @@ test_expect_success 'refuse to merge ancestors of HEAD' '
 	test_cmp_rev HEAD $before
 '
 
+test_expect_success 'root commits' '
+	git checkout --orphan unrelated &&
+	(GIT_AUTHOR_NAME="Parsnip" GIT_AUTHOR_EMAIL="root@example.com" \
+	 test_commit second-root) &&
+	test_commit third-root &&
+	cat >script-from-scratch <<-\EOF &&
+	pick third-root
+	label first-branch
+	reset [new root]
+	pick second-root
+	merge first-branch # Merge the 3rd root
+	EOF
+	test_config sequence.editor \""$PWD"/replace-editor.sh\" &&
+	test_tick &&
+	git rebase -i --force --root -r &&
+	test "Parsnip" = "$(git show -s --format=%an HEAD^)" &&
+	test $(git rev-parse second-root^0) != $(git rev-parse HEAD^) &&
+	test $(git rev-parse second-root:second-root.t) = \
+		$(git rev-parse HEAD^:second-root.t) &&
+	test_cmp_graph HEAD <<-\EOF &&
+	*   Merge the 3rd root
+	|\
+	| * third-root
+	* second-root
+	EOF
+
+	: fast forward if possible &&
+	before="$(git rev-parse --verify HEAD)" &&
+	test_might_fail git config --unset sequence.editor &&
+	test_tick &&
+	git rebase -i --root -r &&
+	test_cmp_rev HEAD $before
+'
+
+test_expect_success 'a "merge" into a root commit is a fast-forward' '
+	head=$(git rev-parse HEAD) &&
+	cat >script-from-scratch <<-EOF &&
+	reset [new root]
+	merge $head
+	EOF
+	test_config sequence.editor \""$PWD"/replace-editor.sh\" &&
+	test_tick &&
+	git rebase -i -r HEAD^ &&
+	test_cmp_rev HEAD $head
+'
+
+test_expect_success 'A root commit can be a cousin, treat it that way' '
+	git checkout --orphan khnum &&
+	test_commit yama &&
+	git checkout -b asherah master &&
+	test_commit shamkat &&
+	git merge --allow-unrelated-histories khnum &&
+	test_tick &&
+	git rebase -f -r HEAD^ &&
+	! test_cmp_rev HEAD^2 khnum &&
+	test_cmp_graph HEAD^.. <<-\EOF &&
+	*   Merge branch '\''khnum'\'' into asherah
+	|\
+	| * yama
+	o shamkat
+	EOF
+	test_tick &&
+	git rebase --rebase-merges=rebase-cousins HEAD^ &&
+	test_cmp_graph HEAD^.. <<-\EOF
+	*   Merge branch '\''khnum'\'' into asherah
+	|\
+	| * yama
+	|/
+	o shamkat
+	EOF
+'
+
 test_done