Merge branch 'pw/rebase-r-fixes' into maint

Various bugs in "git rebase -r" have been fixed.

* pw/rebase-r-fixes:
  rebase -r: fix merge -c with a merge strategy
  rebase -r: don't write .git/MERGE_MSG when fast-forwarding
  rebase -i: add another reword test
  rebase -r: make 'merge -c' behave like reword

3 files changed, 98 insertions, 9 deletions

diff --git a/t/lib-rebase.sh b/t/lib-rebase.sh
index dc75b83451..ec6b9b107d 100644
--- a/t/lib-rebase.sh
+++ b/t/lib-rebase.sh
@@ -151,3 +151,59 @@ test_editor_unchanged () {
 	EOF
 	test_cmp expect actual
 }
+
+# Set up an editor for testing reword commands
+# Checks that there are no uncommitted changes when rewording and that the
+# todo-list is reread after each
+set_reword_editor () {
+	>reword-actual &&
+	>reword-oid &&
+
+	# Check rewording keeps the original authorship
+	GIT_AUTHOR_NAME="Reword Author"
+	GIT_AUTHOR_EMAIL="reword.author@example.com"
+	GIT_AUTHOR_DATE=@123456
+
+	write_script reword-sequence-editor.sh <<-\EOF &&
+	todo="$(cat "$1")" &&
+	echo "exec git log -1 --pretty=format:'%an <%ae> %at%n%B%n' \
+		>>reword-actual" >"$1" &&
+	printf "%s\n" "$todo" >>"$1"
+	EOF
+
+	write_script reword-editor.sh <<-EOF &&
+	# Save the oid of the first reworded commit so we can check rebase
+	# fast-forwards to it. Also check that we do not write .git/MERGE_MSG
+	# when fast-forwarding
+	if ! test -s reword-oid
+	then
+		git rev-parse HEAD >reword-oid &&
+		if test -f .git/MERGE_MSG
+		then
+			echo 1>&2 "error: .git/MERGE_MSG exists"
+			exit 1
+		fi
+	fi &&
+	# There should be no uncommited changes
+	git diff --exit-code HEAD &&
+	# The todo-list should be re-read after a reword
+	GIT_SEQUENCE_EDITOR="\"$PWD/reword-sequence-editor.sh\"" \
+		git rebase --edit-todo &&
+	echo edited >>"\$1"
+	EOF
+
+	test_set_editor "$PWD/reword-editor.sh"
+}
+
+# Check the results of a rebase after calling set_reword_editor
+# Pass the commits that were reworded in the order that they were picked
+# Expects the first pick to be a fast-forward
+check_reworded_commits () {
+	test_cmp_rev "$(cat reword-oid)" "$1^{commit}" &&
+	git log --format="%an <%ae> %at%n%B%nedited%n" --no-walk=unsorted "$@" \
+		>reword-expected &&
+	test_cmp reword-expected reword-actual &&
+	git log --format="%an <%ae> %at%n%B" -n $# --first-parent --reverse \
+		>reword-log &&
+	test_cmp reword-expected reword-log
+}
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 66bcbbf952..d877872e8f 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -839,6 +839,19 @@ test_expect_success 'reword' '
 	git show HEAD~2 | grep "C changed"
 '
 
+test_expect_success 'no uncommited changes when rewording the todo list is reloaded' '
+	git checkout E &&
+	test_when_finished "git checkout @{-1}" &&
+	(
+		set_fake_editor &&
+		GIT_SEQUENCE_EDITOR="\"$PWD/fake-editor.sh\"" &&
+		export GIT_SEQUENCE_EDITOR &&
+		set_reword_editor &&
+		FAKE_LINES="reword 1 reword 2" git rebase -i C
+	) &&
+	check_reworded_commits D E
+'
+
 test_expect_success 'rebase -i can copy notes' '
 	git config notes.rewrite.rebase true &&
 	git config notes.rewriteRef "refs/notes/*" &&
diff --git a/t/t3430-rebase-merges.sh b/t/t3430-rebase-merges.sh
index 6748070df5..43c82d9a33 100755
--- a/t/t3430-rebase-merges.sh
+++ b/t/t3430-rebase-merges.sh
@@ -172,19 +172,39 @@ test_expect_success 'failed `merge <branch>` does not crash' '
 	grep "^Merge branch ${SQ}G${SQ}$" .git/rebase-merge/message
 '
 
-test_expect_success 'fast-forward merge -c still rewords' '
-	git checkout -b fast-forward-merge-c H &&
+test_expect_success 'merge -c commits before rewording and reloads todo-list' '
+	cat >script-from-scratch <<-\EOF &&
+	merge -c E B
+	merge -c H G
+	EOF
+
+	git checkout -b merge-c H &&
 	(
-		set_fake_editor &&
-		FAKE_COMMIT_MESSAGE=edited \
-			GIT_SEQUENCE_EDITOR="echo merge -c H G >" \
-			git rebase -ir @^
+		set_reword_editor &&
+		GIT_SEQUENCE_EDITOR="\"$PWD/replace-editor.sh\"" \
+			git rebase -i -r D
 	) &&
-	echo edited >expected &&
-	git log --pretty=format:%B -1 >actual &&
-	test_cmp expected actual
+	check_reworded_commits E H
 '
 
+test_expect_success 'merge -c rewords when a strategy is given' '
+	git checkout -b merge-c-with-strategy H &&
+	write_script git-merge-override <<-\EOF &&
+	echo overridden$1 >G.t
+	git add G.t
+	EOF
+
+	PATH="$PWD:$PATH" \
+	GIT_SEQUENCE_EDITOR="echo merge -c H G >" \
+	GIT_EDITOR="echo edited >>" \
+		git rebase --no-ff -ir -s override -Xxopt E &&
+	test_write_lines overridden--xopt >expect &&
+	test_cmp expect G.t &&
+	test_write_lines H "" edited "" >expect &&
+	git log --format=%B -1 >actual &&
+	test_cmp expect actual
+
+'
 test_expect_success 'with a branch tip that was cherry-picked already' '
 	git checkout -b already-upstream main &&
 	base="$(git rev-parse --verify HEAD)" &&