status: show the branch name if possible in in-progress info

The typical use-case is starting a rebase, do something else, come
back the day after, run "git status" or make a new commit and wonder
what in the world's going on. Which branch is being rebased is
probably the most useful tidbit to help, but the target may help
too.

Ideally, I would have loved to see "rebasing master on
origin/master", but the target ref name is not stored during rebase,
so this patch writes "rebasing master on a78c8c98b" as a
half-measure to remind future users of that potential improvement.

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

3 files changed, 142 insertions, 41 deletions

diff --git a/t/t7512-status-help.sh b/t/t7512-status-help.sh
index b3f6eb9c68..51ab89411f 100755
--- a/t/t7512-status-help.sh
+++ b/t/t7512-status-help.sh
@@ -73,10 +73,11 @@ test_expect_success 'prepare for rebase conflicts' '
 
 test_expect_success 'status when rebase in progress before resolving conflicts' '
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD^^) &&
 	test_must_fail git rebase HEAD^ --onto HEAD^^ &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently rebasing.
+	# You are currently rebasing branch '\''rebase_conflicts'\'' on '\''$ONTO'\''.
 	#   (fix conflicts and then run "git rebase --continue")
 	#   (use "git rebase --skip" to skip this patch)
 	#   (use "git rebase --abort" to check out the original branch)
@@ -97,12 +98,13 @@ test_expect_success 'status when rebase in progress before resolving conflicts'
 test_expect_success 'status when rebase in progress before rebase --continue' '
 	git reset --hard rebase_conflicts &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD^^) &&
 	test_must_fail git rebase HEAD^ --onto HEAD^^ &&
 	echo three >main.txt &&
 	git add main.txt &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently rebasing.
+	# You are currently rebasing branch '\''rebase_conflicts'\'' on '\''$ONTO'\''.
 	#   (all conflicts fixed: run "git rebase --continue")
 	#
 	# Changes to be committed:
@@ -130,10 +132,11 @@ test_expect_success 'prepare for rebase_i_conflicts' '
 
 test_expect_success 'status during rebase -i when conflicts unresolved' '
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short rebase_i_conflicts) &&
 	test_must_fail git rebase -i rebase_i_conflicts &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently rebasing.
+	# You are currently rebasing branch '\''rebase_i_conflicts_second'\'' on '\''$ONTO'\''.
 	#   (fix conflicts and then run "git rebase --continue")
 	#   (use "git rebase --skip" to skip this patch)
 	#   (use "git rebase --abort" to check out the original branch)
@@ -154,11 +157,12 @@ test_expect_success 'status during rebase -i when conflicts unresolved' '
 test_expect_success 'status during rebase -i after resolving conflicts' '
 	git reset --hard rebase_i_conflicts_second &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short rebase_i_conflicts) &&
 	test_must_fail git rebase -i rebase_i_conflicts &&
 	git add main.txt &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently rebasing.
+	# You are currently rebasing branch '\''rebase_i_conflicts_second'\'' on '\''$ONTO'\''.
 	#   (all conflicts fixed: run "git rebase --continue")
 	#
 	# Changes to be committed:
@@ -182,10 +186,11 @@ test_expect_success 'status when rebasing -i in edit mode' '
 	FAKE_LINES="1 edit 2" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD~2) &&
 	git rebase -i HEAD~2 &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently editing a commit during a rebase.
+	# You are currently editing a commit while rebasing branch '\''rebase_i_edit'\'' on '\''$ONTO'\''.
 	#   (use "git commit --amend" to amend the current commit)
 	#   (use "git rebase --continue" once you are satisfied with your changes)
 	#
@@ -206,11 +211,12 @@ test_expect_success 'status when splitting a commit' '
 	FAKE_LINES="1 edit 2 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD~3) &&
 	git rebase -i HEAD~3 &&
 	git reset HEAD^ &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently splitting a commit during a rebase.
+	# You are currently splitting a commit while rebasing branch '\''split_commit'\'' on '\''$ONTO'\''.
 	#   (Once your working directory is clean, run "git rebase --continue")
 	#
 	# Changes not staged for commit:
@@ -236,11 +242,12 @@ test_expect_success 'status after editing the last commit with --amend during a
 	FAKE_LINES="1 2 edit 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD~3) &&
 	git rebase -i HEAD~3 &&
 	git commit --amend -m "foo" &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently editing a commit during a rebase.
+	# You are currently editing a commit while rebasing branch '\''amend_last'\'' on '\''$ONTO'\''.
 	#   (use "git commit --amend" to amend the current commit)
 	#   (use "git rebase --continue" once you are satisfied with your changes)
 	#
@@ -265,11 +272,12 @@ test_expect_success 'status: (continue first edit) second edit' '
 	FAKE_LINES="edit 1 edit 2 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD~3) &&
 	git rebase -i HEAD~3 &&
 	git rebase --continue &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently editing a commit during a rebase.
+	# You are currently editing a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
 	#   (use "git commit --amend" to amend the current commit)
 	#   (use "git rebase --continue" once you are satisfied with your changes)
 	#
@@ -285,12 +293,13 @@ test_expect_success 'status: (continue first edit) second edit and split' '
 	FAKE_LINES="edit 1 edit 2 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD~3) &&
 	git rebase -i HEAD~3 &&
 	git rebase --continue &&
 	git reset HEAD^ &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently splitting a commit during a rebase.
+	# You are currently splitting a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
 	#   (Once your working directory is clean, run "git rebase --continue")
 	#
 	# Changes not staged for commit:
@@ -311,12 +320,13 @@ test_expect_success 'status: (continue first edit) second edit and amend' '
 	FAKE_LINES="edit 1 edit 2 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD~3) &&
 	git rebase -i HEAD~3 &&
 	git rebase --continue &&
 	git commit --amend -m "foo" &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently editing a commit during a rebase.
+	# You are currently editing a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
 	#   (use "git commit --amend" to amend the current commit)
 	#   (use "git rebase --continue" once you are satisfied with your changes)
 	#
@@ -332,12 +342,13 @@ test_expect_success 'status: (amend first edit) second edit' '
 	FAKE_LINES="edit 1 edit 2 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD~3) &&
 	git rebase -i HEAD~3 &&
 	git commit --amend -m "a" &&
 	git rebase --continue &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently editing a commit during a rebase.
+	# You are currently editing a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
 	#   (use "git commit --amend" to amend the current commit)
 	#   (use "git rebase --continue" once you are satisfied with your changes)
 	#
@@ -353,13 +364,14 @@ test_expect_success 'status: (amend first edit) second edit and split' '
 	FAKE_LINES="edit 1 edit 2 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD~3) &&
 	git rebase -i HEAD~3 &&
 	git commit --amend -m "b" &&
 	git rebase --continue &&
 	git reset HEAD^ &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently splitting a commit during a rebase.
+	# You are currently splitting a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
 	#   (Once your working directory is clean, run "git rebase --continue")
 	#
 	# Changes not staged for commit:
@@ -380,13 +392,14 @@ test_expect_success 'status: (amend first edit) second edit and amend' '
 	FAKE_LINES="edit 1 edit 2 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD~3) &&
 	git rebase -i HEAD~3 &&
 	git commit --amend -m "c" &&
 	git rebase --continue &&
 	git commit --amend -m "d" &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently editing a commit during a rebase.
+	# You are currently editing a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
 	#   (use "git commit --amend" to amend the current commit)
 	#   (use "git rebase --continue" once you are satisfied with your changes)
 	#
@@ -402,14 +415,15 @@ test_expect_success 'status: (split first edit) second edit' '
 	FAKE_LINES="edit 1 edit 2 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD~3) &&
 	git rebase -i HEAD~3 &&
 	git reset HEAD^ &&
 	git add main.txt &&
 	git commit -m "e" &&
 	git rebase --continue &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently editing a commit during a rebase.
+	# You are currently editing a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
 	#   (use "git commit --amend" to amend the current commit)
 	#   (use "git rebase --continue" once you are satisfied with your changes)
 	#
@@ -425,15 +439,16 @@ test_expect_success 'status: (split first edit) second edit and split' '
 	FAKE_LINES="edit 1 edit 2 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD~3) &&
 	git rebase -i HEAD~3 &&
 	git reset HEAD^ &&
 	git add main.txt &&
 	git commit --amend -m "f" &&
 	git rebase --continue &&
 	git reset HEAD^ &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently splitting a commit during a rebase.
+	# You are currently splitting a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
 	#   (Once your working directory is clean, run "git rebase --continue")
 	#
 	# Changes not staged for commit:
@@ -454,15 +469,16 @@ test_expect_success 'status: (split first edit) second edit and amend' '
 	FAKE_LINES="edit 1 edit 2 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD~3) &&
 	git rebase -i HEAD~3 &&
 	git reset HEAD^ &&
 	git add main.txt &&
 	git commit --amend -m "g" &&
 	git rebase --continue &&
 	git commit --amend -m "h" &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently editing a commit during a rebase.
+	# You are currently editing a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
 	#   (use "git commit --amend" to amend the current commit)
 	#   (use "git rebase --continue" once you are satisfied with your changes)
 	#
@@ -558,7 +574,7 @@ test_expect_success 'status when bisecting' '
 	git bisect good one_bisect &&
 	cat >expected <<-\EOF &&
 	# Not currently on any branch.
-	# You are currently bisecting.
+	# You are currently bisecting branch '\''bisect'\''.
 	#   (use "git bisect reset" to get back to the original branch)
 	#
 	nothing to commit (use -u to show untracked files)
@@ -577,10 +593,11 @@ test_expect_success 'status when rebase conflicts with statushints disabled' '
 	test_commit two_statushints main.txt two &&
 	test_commit three_statushints main.txt three &&
 	test_when_finished "git rebase --abort" &&
+	ONTO=$(git rev-parse --short HEAD^^) &&
 	test_must_fail git rebase HEAD^ --onto HEAD^^ &&
-	cat >expected <<-\EOF &&
+	cat >expected <<-EOF &&
 	# Not currently on any branch.
-	# You are currently rebasing.
+	# You are currently rebasing branch '\''statushints_disabled'\'' on '\''$ONTO'\''.
 	#
 	# Unmerged paths:
 	#	both modified:      main.txt
diff --git a/wt-status.c b/wt-status.c
index d7cfe8f31c..983e2f4b5e 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -872,7 +872,14 @@ static void show_rebase_in_progress(struct wt_status *s,
 	struct stat st;
 
 	if (has_unmerged(s)) {
-		status_printf_ln(s, color, _("You are currently rebasing."));
+		if (state->branch)
+			status_printf_ln(s, color,
+					 _("You are currently rebasing branch '%s' on '%s'."),
+					 state->branch,
+					 state->onto);
+		else
+			status_printf_ln(s, color,
+					 _("You are currently rebasing."));
 		if (advice_status_hints) {
 			status_printf_ln(s, color,
 				_("  (fix conflicts and then run \"git rebase --continue\")"));
@@ -882,17 +889,38 @@ static void show_rebase_in_progress(struct wt_status *s,
 				_("  (use \"git rebase --abort\" to check out the original branch)"));
 		}
 	} else if (state->rebase_in_progress || !stat(git_path("MERGE_MSG"), &st)) {
-		status_printf_ln(s, color, _("You are currently rebasing."));
+		if (state->branch)
+			status_printf_ln(s, color,
+					 _("You are currently rebasing branch '%s' on '%s'."),
+					 state->branch,
+					 state->onto);
+		else
+			status_printf_ln(s, color,
+					 _("You are currently rebasing."));
 		if (advice_status_hints)
 			status_printf_ln(s, color,
 				_("  (all conflicts fixed: run \"git rebase --continue\")"));
 	} else if (split_commit_in_progress(s)) {
-		status_printf_ln(s, color, _("You are currently splitting a commit during a rebase."));
+		if (state->branch)
+			status_printf_ln(s, color,
+					 _("You are currently splitting a commit while rebasing branch '%s' on '%s'."),
+					 state->branch,
+					 state->onto);
+		else
+			status_printf_ln(s, color,
+					 _("You are currently splitting a commit during a rebase."));
 		if (advice_status_hints)
 			status_printf_ln(s, color,
 				_("  (Once your working directory is clean, run \"git rebase --continue\")"));
 	} else {
-		status_printf_ln(s, color, _("You are currently editing a commit during a rebase."));
+		if (state->branch)
+			status_printf_ln(s, color,
+					 _("You are currently editing a commit while rebasing branch '%s' on '%s'."),
+					 state->branch,
+					 state->onto);
+		else
+			status_printf_ln(s, color,
+					 _("You are currently editing a commit during a rebase."));
 		if (advice_status_hints && !s->amend) {
 			status_printf_ln(s, color,
 				_("  (use \"git commit --amend\" to amend the current commit)"));
@@ -923,16 +951,57 @@ static void show_bisect_in_progress(struct wt_status *s,
 				struct wt_status_state *state,
 				const char *color)
 {
-	status_printf_ln(s, color, _("You are currently bisecting."));
+	if (state->branch)
+		status_printf_ln(s, color,
+				 _("You are currently bisecting branch '%s'."),
+				 state->branch);
+	else
+		status_printf_ln(s, color,
+				 _("You are currently bisecting."));
 	if (advice_status_hints)
 		status_printf_ln(s, color,
 			_("  (use \"git bisect reset\" to get back to the original branch)"));
 	wt_status_print_trailer(s);
 }
 
+/*
+ * Extract branch information from rebase/bisect
+ */
+static void read_and_strip_branch(struct strbuf *sb,
+				  const char **branch,
+				  const char *path)
+{
+	unsigned char sha1[20];
+
+	strbuf_reset(sb);
+	if (strbuf_read_file(sb, git_path("%s", path), 0) <= 0)
+		return;
+
+	while (sb->len && sb->buf[sb->len - 1] == '\n')
+		strbuf_setlen(sb, sb->len - 1);
+	if (!sb->len)
+		return;
+	if (!prefixcmp(sb->buf, "refs/heads/"))
+		*branch = sb->buf + strlen("refs/heads/");
+	else if (!prefixcmp(sb->buf, "refs/"))
+		*branch = sb->buf;
+	else if (!get_sha1_hex(sb->buf, sha1)) {
+		const char *abbrev;
+		abbrev = find_unique_abbrev(sha1, DEFAULT_ABBREV);
+		strbuf_reset(sb);
+		strbuf_addstr(sb, abbrev);
+		*branch = sb->buf;
+	} else if (!strcmp(sb->buf, "detached HEAD")) /* rebase */
+		;
+	else			/* bisect */
+		*branch = sb->buf;
+}
+
 static void wt_status_print_state(struct wt_status *s)
 {
 	const char *state_color = color(WT_STATUS_HEADER, s);
+	struct strbuf branch = STRBUF_INIT;
+	struct strbuf onto = STRBUF_INIT;
 	struct wt_status_state state;
 	struct stat st;
 
@@ -947,17 +1016,28 @@ static void wt_status_print_state(struct wt_status *s)
 				state.am_empty_patch = 1;
 		} else {
 			state.rebase_in_progress = 1;
+			read_and_strip_branch(&branch, &state.branch,
+					      "rebase-apply/head-name");
+			read_and_strip_branch(&onto, &state.onto,
+					      "rebase-apply/onto");
 		}
 	} else if (!stat(git_path("rebase-merge"), &st)) {
 		if (!stat(git_path("rebase-merge/interactive"), &st))
 			state.rebase_interactive_in_progress = 1;
 		else
 			state.rebase_in_progress = 1;
+		read_and_strip_branch(&branch, &state.branch,
+				      "rebase-merge/head-name");
+		read_and_strip_branch(&onto, &state.onto,
+				      "rebase-merge/onto");
 	} else if (!stat(git_path("CHERRY_PICK_HEAD"), &st)) {
 		state.cherry_pick_in_progress = 1;
 	}
-	if (!stat(git_path("BISECT_LOG"), &st))
+	if (!stat(git_path("BISECT_LOG"), &st)) {
 		state.bisect_in_progress = 1;
+		read_and_strip_branch(&branch, &state.branch,
+				      "BISECT_START");
+	}
 
 	if (state.merge_in_progress)
 		show_merge_in_progress(s, &state, state_color);
@@ -969,6 +1049,8 @@ static void wt_status_print_state(struct wt_status *s)
 		show_cherry_pick_in_progress(s, &state, state_color);
 	if (state.bisect_in_progress)
 		show_bisect_in_progress(s, &state, state_color);
+	strbuf_release(&branch);
+	strbuf_release(&onto);
 }
 
 void wt_status_print(struct wt_status *s)
diff --git a/wt-status.h b/wt-status.h
index 236b41fd34..81e1dcf84d 100644
--- a/wt-status.h
+++ b/wt-status.h
@@ -79,6 +79,8 @@ struct wt_status_state {
 	int rebase_interactive_in_progress;
 	int cherry_pick_in_progress;
 	int bisect_in_progress;
+	const char *branch;
+	const char *onto;
 };
 
 void wt_status_prepare(struct wt_status *s);