Merge branch 'pw/rebase-keep-base-fixes'

"git rebase --keep-base" used to discard the commits that are
already cherry-picked to the upstream, even when "keep-base" meant
that the base, on top of which the history is being rebuilt, does
not yet include these cherry-picked commits.  The --keep-base
option now implies --reapply-cherry-picks and --no-fork-point
options.

* pw/rebase-keep-base-fixes:
  rebase --keep-base: imply --no-fork-point
  rebase --keep-base: imply --reapply-cherry-picks
  rebase: factor out branch_base calculation
  rebase: rename merge_base to branch_base
  rebase: store orig_head as a commit
  rebase: be stricter when reading state files containing oids
  t3416: set $EDITOR in subshell
  t3416: tighten two tests

2 files changed, 49 insertions, 15 deletions

diff --git a/t/t3416-rebase-onto-threedots.sh b/t/t3416-rebase-onto-threedots.sh
index 3e04802cb00..ea501f2b42b 100755
--- a/t/t3416-rebase-onto-threedots.sh
+++ b/t/t3416-rebase-onto-threedots.sh
@@ -79,8 +79,10 @@ test_expect_success 'rebase -i --onto main...topic' '
 	git reset --hard &&
 	git checkout topic &&
 	git reset --hard G &&
-	set_fake_editor &&
-	EXPECT_COUNT=1 git rebase -i --onto main...topic F &&
+	(
+		set_fake_editor &&
+		EXPECT_COUNT=1 git rebase -i --onto main...topic F
+	) &&
 	git rev-parse HEAD^1 >actual &&
 	git rev-parse C^0 >expect &&
 	test_cmp expect actual
@@ -90,20 +92,22 @@ test_expect_success 'rebase -i --onto main...' '
 	git reset --hard &&
 	git checkout topic &&
 	git reset --hard G &&
-	set_fake_editor &&
-	EXPECT_COUNT=1 git rebase -i --onto main... F &&
+	(
+		set_fake_editor &&
+		EXPECT_COUNT=1 git rebase -i --onto main... F
+	) &&
 	git rev-parse HEAD^1 >actual &&
 	git rev-parse C^0 >expect &&
 	test_cmp expect actual
 '
 
-test_expect_success 'rebase -i --onto main...side' '
+test_expect_success 'rebase --onto main...side requires a single merge-base' '
 	git reset --hard &&
 	git checkout side &&
 	git reset --hard K &&
 
-	set_fake_editor &&
-	test_must_fail git rebase -i --onto main...side J
+	test_must_fail git rebase -i --onto main...side J 2>err &&
+	grep "need exactly one merge base" err
 '
 
 test_expect_success 'rebase --keep-base --onto incompatible' '
@@ -156,8 +160,10 @@ test_expect_success 'rebase -i --keep-base main from topic' '
 	git checkout topic &&
 	git reset --hard G &&
 
-	set_fake_editor &&
-	EXPECT_COUNT=2 git rebase -i --keep-base main &&
+	(
+		set_fake_editor &&
+		EXPECT_COUNT=2 git rebase -i --keep-base main
+	) &&
 	git rev-parse C >base.expect &&
 	git merge-base main HEAD >base.actual &&
 	test_cmp base.expect base.actual &&
@@ -171,8 +177,10 @@ test_expect_success 'rebase -i --keep-base main topic from main' '
 	git checkout main &&
 	git branch -f topic G &&
 
-	set_fake_editor &&
-	EXPECT_COUNT=2 git rebase -i --keep-base main topic &&
+	(
+		set_fake_editor &&
+		EXPECT_COUNT=2 git rebase -i --keep-base main topic
+	) &&
 	git rev-parse C >base.expect &&
 	git merge-base main HEAD >base.actual &&
 	test_cmp base.expect base.actual &&
@@ -182,13 +190,39 @@ test_expect_success 'rebase -i --keep-base main topic from main' '
 	test_cmp expect actual
 '
 
-test_expect_success 'rebase -i --keep-base main from side' '
+test_expect_success 'rebase --keep-base requires a single merge base' '
 	git reset --hard &&
 	git checkout side &&
 	git reset --hard K &&
 
-	set_fake_editor &&
-	test_must_fail git rebase -i --keep-base main
+	test_must_fail git rebase -i --keep-base main 2>err &&
+	grep "need exactly one merge base with branch" err
+'
+
+test_expect_success 'rebase --keep-base keeps cherry picks' '
+	git checkout -f -B main E &&
+	git cherry-pick F &&
+	(
+		set_fake_editor &&
+		EXPECT_COUNT=2 git rebase -i --keep-base HEAD G
+	) &&
+	test_cmp_rev HEAD G
+'
+
+test_expect_success 'rebase --keep-base --no-reapply-cherry-picks' '
+	git checkout -f -B main E &&
+	git cherry-pick F &&
+	(
+		set_fake_editor &&
+		EXPECT_COUNT=1 git rebase -i --keep-base \
+					--no-reapply-cherry-picks HEAD G
+	) &&
+	test_cmp_rev HEAD^ C
+'
+
+# This must be the last test in this file
+test_expect_success '$EDITOR and friends are unchanged' '
+	test_editor_unchanged
 '
 
 test_done
diff --git a/t/t3431-rebase-fork-point.sh b/t/t3431-rebase-fork-point.sh
index 1d0b15380ed..70e81363569 100755
--- a/t/t3431-rebase-fork-point.sh
+++ b/t/t3431-rebase-fork-point.sh
@@ -50,7 +50,7 @@ test_rebase () {
 
 test_rebase 'G F E D B A'
 test_rebase 'G F D B A' --onto D
-test_rebase 'G F B A' --keep-base
+test_rebase 'G F C B A' --keep-base
 test_rebase 'G F C E D B A' --no-fork-point
 test_rebase 'G F C D B A' --no-fork-point --onto D
 test_rebase 'G F C B A' --no-fork-point --keep-base