[v3,2/2] rebase -i: introduce the 'break' command

Commit Message

Philippe Blain via GitGitGadget Oct. 12, 2018, 1:14 p.m. UTC

From: Johannes Schindelin <[e-mail]>

The 'edit' command can be used to cherry-pick a commit and then
immediately drop out of the interactive rebase, with exit code 0, to let
the user amend the commit, or test it, or look around.

Sometimes this functionality would come in handy *without*
cherry-picking a commit, e.g. to interrupt the interactive rebase even
before cherry-picking a commit, or immediately after an 'exec' or a
'merge'.

This commit introduces that functionality, as the spanking new 'break'
command.

Suggested-by: Stefan Beller <[e-mail]>
Signed-off-by: Johannes Schindelin <[e-mail]>
---
 Documentation/git-rebase.txt |  3 +++
 rebase-interactive.c         |  1 +
 sequencer.c                  | 24 +++++++++++++++++++++++-
 t/lib-rebase.sh              |  2 +-
 t/t3418-rebase-continue.sh   |  9 +++++++++
 5 files changed, 37 insertions(+), 2 deletions(-)

Comments

Junio C Hamano Oct. 12, 2018, 2:09 p.m. UTC | #1

"Johannes Schindelin via GitGitGadget" <[e-mail]>
writes:

> @@ -3293,6 +3312,9 @@ static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts)
>  			unlink(rebase_path_stopped_sha());
>  			unlink(rebase_path_amend());
>  			delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
> +
> +			if (item->command == TODO_BREAK)
> +				return stopped_at_head();
>  		}

The earlier one had "break;" here, which broke out of the while()
loop, let the control reach "if (is_reabse_i(opts)) {" block after
the loop, and the block would have noticed that current < nr and
returned 0.  So from the point of view of the overall control flow
of the caller of this function, there is no change relative to v2.
The only difference in v3 is that stopped_at_head() gives a useful
message.

Good.

Johannes Schindelin Oct. 12, 2018, 3:31 p.m. UTC | #2

Hi Junio,

On Fri, 12 Oct 2018, Junio C Hamano wrote:

> "Johannes Schindelin via GitGitGadget" <[e-mail]>
> writes:
> 
> > @@ -3293,6 +3312,9 @@ static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts)
> >  			unlink(rebase_path_stopped_sha());
> >  			unlink(rebase_path_amend());
> >  			delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
> > +
> > +			if (item->command == TODO_BREAK)
> > +				return stopped_at_head();
> >  		}
> 
> The earlier one had "break;" here, which broke out of the while()
> loop, let the control reach "if (is_reabse_i(opts)) {" block after
> the loop, and the block would have noticed that current < nr and
> returned 0.  So from the point of view of the overall control flow
> of the caller of this function, there is no change relative to v2.
> The only difference in v3 is that stopped_at_head() gives a useful
> message.

Well, I should have called out this `break;` -> `return 0;` change, too,
as I think it makes the code flow *a lot* more obvious. As you say, I
relied earlier on the next loop to return early, but that is not what the
`edit` command does: it returns out of the first loop, too.

> 
> Good.

Thanks,
Dscho
> 
>

Patch

diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index d9771bd25b..6b71694b0d 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -561,6 +561,9 @@  By replacing the command "pick" with the command "edit", you can tell
 the files and/or the commit message, amend the commit, and continue
 rebasing.
 
+To interrupt the rebase (just like an "edit" command would do, but without
+cherry-picking any commit first), use the "break" command.
+
 If you just want to edit the commit message for a commit, replace the
 command "pick" with the command "reword".
 
diff --git a/rebase-interactive.c b/rebase-interactive.c
index 0f4119cbae..78f3263fc1 100644
--- a/rebase-interactive.c
+++ b/rebase-interactive.c
@@ -14,6 +14,7 @@  void append_todo_help(unsigned edit_todo, unsigned keep_empty,
 "s, squash <commit> = use commit, but meld into previous commit\n"
 "f, fixup <commit> = like \"squash\", but discard this commit's log message\n"
 "x, exec <command> = run command (the rest of the line) using shell\n"
+"b, break = stop here (continue rebase later with 'git rebase --continue')\n"
 "d, drop <commit> = remove commit\n"
 "l, label <label> = label current HEAD with a name\n"
 "t, reset <label> = reset HEAD to a label\n"
diff --git a/sequencer.c b/sequencer.c
index 8dd6db5a01..ee3961ec63 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -1416,6 +1416,7 @@  enum todo_command {
 	TODO_SQUASH,
 	/* commands that do something else than handling a single commit */
 	TODO_EXEC,
+	TODO_BREAK,
 	TODO_LABEL,
 	TODO_RESET,
 	TODO_MERGE,
@@ -1437,6 +1438,7 @@  static struct {
 	{ 'f', "fixup" },
 	{ 's', "squash" },
 	{ 'x', "exec" },
+	{ 'b', "break" },
 	{ 'l', "label" },
 	{ 't', "reset" },
 	{ 'm', "merge" },
@@ -1964,7 +1966,7 @@  static int parse_insn_line(struct todo_item *item, const char *bol, char *eol)
 	padding = strspn(bol, " \t");
 	bol += padding;
 
-	if (item->command == TODO_NOOP) {
+	if (item->command == TODO_NOOP || item->command == TODO_BREAK) {
 		if (bol != eol)
 			return error(_("%s does not accept arguments: '%s'"),
 				     command_to_string(item->command), bol);
@@ -3247,6 +3249,23 @@  static int checkout_onto(struct replay_opts *opts,
 	return update_ref(NULL, "ORIG_HEAD", &oid, NULL, 0, UPDATE_REFS_MSG_ON_ERR);
 }
 
+static int stopped_at_head(void)
+{
+	struct object_id head;
+	struct commit *commit;
+	struct commit_message message;
+
+	if (get_oid("HEAD", &head) || !(commit = lookup_commit(&head)) ||
+	    parse_commit(commit) || get_message(commit, &message))
+		fprintf(stderr, _("Stopped at HEAD\n"));
+	else {
+		fprintf(stderr, _("Stopped at %s\n"), message.label);
+		free_message(commit, &message);
+	}
+	return 0;
+
+}
+
 static const char rescheduled_advice[] =
 N_("Could not execute the todo command\n"
 "\n"
@@ -3293,6 +3312,9 @@  static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts)
 			unlink(rebase_path_stopped_sha());
 			unlink(rebase_path_amend());
 			delete_ref(NULL, "REBASE_HEAD", NULL, REF_NO_DEREF);
+
+			if (item->command == TODO_BREAK)
+				return stopped_at_head();
 		}
 		if (item->command <= TODO_SQUASH) {
 			if (is_rebase_i(opts))
diff --git a/t/lib-rebase.sh b/t/lib-rebase.sh
index 25a77ee5cb..584604ee63 100644
--- a/t/lib-rebase.sh
+++ b/t/lib-rebase.sh
@@ -49,7 +49,7 @@  set_fake_editor () {
 		case $line in
 		squash|fixup|edit|reword|drop)
 			action="$line";;
-		exec*)
+		exec*|break)
 			echo "$line" | sed 's/_/ /g' >> "$1";;
 		"#")
 			echo '# comment' >> "$1";;
diff --git a/t/t3418-rebase-continue.sh b/t/t3418-rebase-continue.sh
index c145dbac38..185a491089 100755
--- a/t/t3418-rebase-continue.sh
+++ b/t/t3418-rebase-continue.sh
@@ -239,5 +239,14 @@  test_rerere_autoupdate -m
 GIT_SEQUENCE_EDITOR=: && export GIT_SEQUENCE_EDITOR
 test_rerere_autoupdate -i
 test_rerere_autoupdate --preserve-merges
+unset GIT_SEQUENCE_EDITOR
+
+test_expect_success 'the todo command "break" works' '
+	rm -f execed &&
+	FAKE_LINES="break exec_>execed" git rebase -i HEAD &&
+	test_path_is_missing execed &&
+	git rebase --continue &&
+	test_path_is_file execed
+'
 
 test_done