status: improve rebase todo list parsing

When there is rebase in progress "git status" displays the last couple
of completed and the next couple of pending commands from the todo
list. When it does this is tries to abbreviate the object ids of
the commits to be picked. Unfortunately it does not abbreviate the
object ids when the line starts with "fixup -C" or "merge -C". It
also mistakenly replaces the refname in "reset main" and "update-ref
refs/heads/main" with the object id that the ref points to. Use
the function added in the last commit to parse the command name and
only try to abbreviate the argument for commands that take an object
id. When trying to abbreviate an object id, only replace the object
name if it starts with the abbreviated object id so that labels or
branch names that contain only hex digits are left unchanged.

Comments are now processed after stripping any leading
whitespace from the line. This matches what the sequencer does in
parse_insn_line(). The existing test cases are updated to test a
wider variety of commands. Only the pending commands in the tests
are changed to avoid removing existing coverage.

Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Author: phillipwood

t/t7512-status-help.sh

@@ -224,7 +224,7 @@ test_expect_success 'status when splitting a commit' '
 	COMMIT3=$(git rev-parse --short split_commit) &&
 	test_commit four_split main.txt four &&
 	COMMIT4=$(git rev-parse --short split_commit) &&
-	FAKE_LINES="1 edit 2 3" &&
+	FAKE_LINES="reword 1 edit 2 fixup_-C 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
 	ONTO=$(git rev-parse --short HEAD~3) &&
@@ -233,10 +233,10 @@ test_expect_success 'status when splitting a commit' '
 	cat >expected <<EOF &&
 interactive rebase in progress; onto $ONTO
 Last commands done (2 commands done):
-   pick $COMMIT2 # two_split
+   reword $COMMIT2 # two_split
    edit $COMMIT3 # three_split
 Next command to do (1 remaining command):
-   pick $COMMIT4 # four_split
+   fixup -C $COMMIT4 # four_split
   (use "git rebase --edit-todo" to view and edit)
 You are currently splitting a commit while rebasing branch '\''split_commit'\'' on '\''$ONTO'\''.
   (Once your working directory is clean, run "git rebase --continue")
@@ -297,7 +297,7 @@ test_expect_success 'prepare for several edits' '
 
 
 test_expect_success 'status: (continue first edit) second edit' '
-	FAKE_LINES="edit 1 edit 2 3" &&
+	FAKE_LINES="edit 1 edit 2 drop 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
 	COMMIT2=$(git rev-parse --short several_edits^^) &&
@@ -312,7 +312,7 @@ Last commands done (2 commands done):
    edit $COMMIT2 # two_edits
    edit $COMMIT3 # three_edits
 Next command to do (1 remaining command):
-   pick $COMMIT4 # four_edits
+   drop $COMMIT4 # four_edits
   (use "git rebase --edit-todo" to view and edit)
 You are currently editing a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
   (use "git commit --amend" to amend the current commit)
@@ -327,7 +327,7 @@ EOF
 
 test_expect_success 'status: (continue first edit) second edit and split' '
 	git reset --hard several_edits &&
-	FAKE_LINES="edit 1 edit 2 3" &&
+	FAKE_LINES="edit 1 edit 2 squash 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
 	COMMIT2=$(git rev-parse --short several_edits^^) &&
@@ -343,7 +343,7 @@ Last commands done (2 commands done):
    edit $COMMIT2 # two_edits
    edit $COMMIT3 # three_edits
 Next command to do (1 remaining command):
-   pick $COMMIT4 # four_edits
+   squash $COMMIT4 # four_edits
   (use "git rebase --edit-todo" to view and edit)
 You are currently splitting a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
   (Once your working directory is clean, run "git rebase --continue")
@@ -362,7 +362,7 @@ EOF
 
 test_expect_success 'status: (continue first edit) second edit and amend' '
 	git reset --hard several_edits &&
-	FAKE_LINES="edit 1 edit 2 3" &&
+	FAKE_LINES="edit 1 edit 2 fixup 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
 	COMMIT2=$(git rev-parse --short several_edits^^) &&
@@ -378,7 +378,7 @@ Last commands done (2 commands done):
    edit $COMMIT2 # two_edits
    edit $COMMIT3 # three_edits
 Next command to do (1 remaining command):
-   pick $COMMIT4 # four_edits
+   fixup $COMMIT4 # four_edits
   (use "git rebase --edit-todo" to view and edit)
 You are currently editing a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
   (use "git commit --amend" to amend the current commit)
@@ -393,7 +393,7 @@ EOF
 
 test_expect_success 'status: (amend first edit) second edit' '
 	git reset --hard several_edits &&
-	FAKE_LINES="edit 1 edit 2 3" &&
+	FAKE_LINES="edit 1 edit 2 fixup_-c 3" &&
 	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
 	COMMIT2=$(git rev-parse --short several_edits^^) &&
@@ -409,7 +409,7 @@ Last commands done (2 commands done):
    edit $COMMIT2 # two_edits
    edit $COMMIT3 # three_edits
 Next command to do (1 remaining command):
-   pick $COMMIT4 # four_edits
+   fixup -c $COMMIT4 # four_edits
   (use "git rebase --edit-todo" to view and edit)
 You are currently editing a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
   (use "git commit --amend" to amend the current commit)
@@ -460,14 +460,20 @@ EOF
 
 test_expect_success 'status: (amend first edit) second edit and amend' '
 	git reset --hard several_edits &&
-	FAKE_LINES="edit 1 edit 2 3" &&
-	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
 	COMMIT2=$(git rev-parse --short several_edits^^) &&
 	COMMIT3=$(git rev-parse --short several_edits^) &&
 	COMMIT4=$(git rev-parse --short several_edits) &&
 	ONTO=$(git rev-parse --short HEAD~3) &&
-	git rebase -i HEAD~3 &&
+	cat >todo <<-EOF &&
+	edit several_edits^^ # two_edits
+	edit several_edits^ # three_edits
+	merge $(git rev-parse main) $(git rev-parse several_edits)
+	EOF
+	(
+		set_replace_editor todo &&
+		git rebase -i HEAD~3
+	) &&
 	git commit --amend -m "c" &&
 	git rebase --continue &&
 	git commit --amend -m "d" &&
@@ -477,7 +483,7 @@ Last commands done (2 commands done):
    edit $COMMIT2 # two_edits
    edit $COMMIT3 # three_edits
 Next command to do (1 remaining command):
-   pick $COMMIT4 # four_edits
+   merge $(git rev-parse --short main) $COMMIT4
   (use "git rebase --edit-todo" to view and edit)
 You are currently editing a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
   (use "git commit --amend" to amend the current commit)
@@ -525,14 +531,21 @@ EOF
 
 test_expect_success 'status: (split first edit) second edit and split' '
 	git reset --hard several_edits &&
-	FAKE_LINES="edit 1 edit 2 3" &&
-	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
 	COMMIT2=$(git rev-parse --short several_edits^^) &&
 	COMMIT3=$(git rev-parse --short several_edits^) &&
 	COMMIT4=$(git rev-parse --short several_edits) &&
+	cat >todo <<-EOF &&
+	edit several_edits^^ # two_edits
+	edit several_edits^ # three_edits
+	reset $(git rev-parse main)
+	merge -C several_edits topic # title
+	EOF
 	ONTO=$(git rev-parse --short HEAD~3) &&
-	git rebase -i HEAD~3 &&
+	(
+		set_replace_editor todo &&
+		git rebase -i HEAD~3
+	) &&
 	git reset HEAD^ &&
 	git add main.txt &&
 	git commit --amend -m "f" &&
@@ -543,8 +556,9 @@ interactive rebase in progress; onto $ONTO
 Last commands done (2 commands done):
    edit $COMMIT2 # two_edits
    edit $COMMIT3 # three_edits
-Next command to do (1 remaining command):
-   pick $COMMIT4 # four_edits
+Next commands to do (2 remaining commands):
+   reset $(git rev-parse --short main)
+   merge -C $COMMIT4 topic # title
   (use "git rebase --edit-todo" to view and edit)
 You are currently splitting a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
   (Once your working directory is clean, run "git rebase --continue")
@@ -563,14 +577,21 @@ EOF
 
 test_expect_success 'status: (split first edit) second edit and amend' '
 	git reset --hard several_edits &&
-	FAKE_LINES="edit 1 edit 2 3" &&
-	export FAKE_LINES &&
 	test_when_finished "git rebase --abort" &&
+	git branch cafe main &&
 	COMMIT2=$(git rev-parse --short several_edits^^) &&
 	COMMIT3=$(git rev-parse --short several_edits^) &&
-	COMMIT4=$(git rev-parse --short several_edits) &&
+	cat >todo <<-EOF &&
+	edit several_edits^^ # two_edits
+	edit several_edits^ # three_edits
+	update-ref refs/heads/main
+	reset cafe
+	EOF
 	ONTO=$(git rev-parse --short HEAD~3) &&
-	git rebase -i HEAD~3 &&
+	(
+		set_replace_editor todo &&
+		git rebase -i HEAD~3
+	) &&
 	git reset HEAD^ &&
 	git add main.txt &&
 	git commit --amend -m "g" &&
@@ -581,8 +602,9 @@ interactive rebase in progress; onto $ONTO
 Last commands done (2 commands done):
    edit $COMMIT2 # two_edits
    edit $COMMIT3 # three_edits
-Next command to do (1 remaining command):
-   pick $COMMIT4 # four_edits
+Next commands to do (2 remaining commands):
+   update-ref refs/heads/main
+   reset cafe
   (use "git rebase --edit-todo" to view and edit)
 You are currently editing a commit while rebasing branch '\''several_edits'\'' on '\''$ONTO'\''.
   (use "git commit --amend" to amend the current commit)

wt-status.c

@@ -1365,35 +1365,108 @@ static int split_commit_in_progress(struct wt_status *s)
 	return split_in_progress;
 }
 
+static void abbrev_oid_in_line(struct repository *r,
+			       struct strbuf *line, char **pp)
+{
+	char *p = *pp;
+	char *end_of_object_name, saved;
+	const char *abbrev;
+	struct object_id oid;
+	bool have_oid;
+
+	p += strspn(p, " \t");
+	end_of_object_name = p + strcspn(p, " \t");
+	/*
+	 * The for "merge" and "reset" the object name may be a label or
+	 * ref rather than a hex object id. Only abbreviate the object
+	 * name if it is a hex object id.
+	 */
+	for (const char *q = p; q < end_of_object_name; q++) {
+		if (!isxdigit(*q))
+			goto out;
+	}
+	saved = *end_of_object_name;
+	*end_of_object_name = '\0';
+	have_oid = !repo_get_oid(r, p, &oid);
+	*end_of_object_name = saved;
+	if (!have_oid)
+		goto out; /* object name was a label */
+	abbrev = repo_find_unique_abbrev(r, &oid, DEFAULT_ABBREV);
+	if (!starts_with(p, abbrev))
+		goto out; /* object name was a refname containing only xdigits */
+	p += strlen(abbrev);
+	strbuf_remove(line, p - line->buf, end_of_object_name - p);
+	end_of_object_name = p;
+out:
+	*pp = end_of_object_name;
+}
+
+static void skip_dash_c(char **pp) {
+	char *p = *pp;
+
+	p += strspn(p, " \t");
+	/* The (void) cast is required to silence -Wunused_value */
+	(void)(skip_prefix(p, "-C", &p) || skip_prefix(p, "-c", &p));
+	*pp = p;
+}
+
 /*
  * Turn
  * "pick d6a2f0303e897ec257dd0e0a39a5ccb709bc2047 some message"
  * into
  * "pick d6a2f03 some message"
  *
- * The function assumes that the line does not contain useless spaces
- * before or after the command.
+ * Returns false on comment lines, true otherwise
  */
-static void abbrev_oid_in_line(struct repository *r, struct strbuf *line)
+static bool format_todo_line(struct repository *r, struct strbuf *line)
 {
-	struct string_list split = STRING_LIST_INIT_DUP;
-	struct object_id oid;
+	enum todo_command cmd;
+	char *p = line->buf;
 
-	if (starts_with(line->buf, "exec ") ||
-	    starts_with(line->buf, "x ") ||
-	    starts_with(line->buf, "label ") ||
-	    starts_with(line->buf, "l "))
-		return;
+	if (!sequencer_parse_todo_command((const char**)&p, &cmd))
+		return true; /* keep invalid lines */
+
+	switch (cmd) {
+	case TODO_COMMENT:
+		return false;
+
+	case TODO_MERGE:
+		skip_dash_c(&p);
+		while (true) {
+			p += strspn(p, " \t");
+			if (!p[0] || (p[0] == '#' && (!p[1] || isspace(p[1]))))
+				break;
+			abbrev_oid_in_line(r, line, &p);
+		}
+		break;
+
+	case TODO_FIXUP:
+		skip_dash_c(&p);
+		/* fallthrough */
+	case TODO_DROP:
+	case TODO_EDIT:
+	case TODO_PICK:
+	case TODO_RESET:
+	case TODO_REVERT:
+	case TODO_REWORD:
+	case TODO_SQUASH:
+		abbrev_oid_in_line(r, line, &p);
+		break;
 
-	if ((2 <= string_list_split(&split, line->buf, " ", 2)) &&
-	    !repo_get_oid(r, split.items[1].string, &oid)) {
-		strbuf_reset(line);
-		strbuf_addf(line, "%s ", split.items[0].string);
-		strbuf_add_unique_abbrev(line, &oid, DEFAULT_ABBREV);
-		for (size_t i = 2; i < split.nr; i++)
-			strbuf_addf(line, " %s", split.items[i].string);
+	/*
+	 * Avoid "default" and instead list all the other commands so
+	 * that -Wswitch warns if a new command is added without handling
+	 * it in this function.
+	 */
+	case TODO_BREAK:
+	case TODO_EXEC:
+	case TODO_LABEL:
+	case TODO_NOOP:
+	case TODO_UPDATE_REF:
+		break;
 	}
-	string_list_clear(&split, 0);
+
+	return true;
 }
 
 static int read_rebase_todolist(struct repository *r, const char *fname, struct string_list *lines)
@@ -1411,13 +1484,9 @@ static int read_rebase_todolist(struct repository *r, const char *fname, struct
 			  repo_git_path_replace(r, &buf, "%s", fname));
 	}
 	while (!strbuf_getline_lf(&buf, f)) {
-		if (starts_with(buf.buf, comment_line_str))
-			continue;
 		strbuf_trim(&buf);
-		if (!buf.len)
-			continue;
-		abbrev_oid_in_line(r, &buf);
-		string_list_append(lines, buf.buf);
+		if (format_todo_line(r, &buf))
+			string_list_append(lines, buf.buf);
 	}
 	fclose(f);