cherry-pick: refuse cherry-pick sequence if index is dirty

Cherry-pick, like merge or rebase, refuses to run when there are changes
in the index. However, if a cherry-pick sequence is requested, this
refusal happens "too late": when the cherry-pick sequence has already
started, and an "--abort" or "--quit" is needed to resume normal
operation.

Normally, when an operation is "in-progress" and you want to go back to
where you were before, "--abort" is the right thing to run. If you run
"git cherry-pick --abort" in this specific situation, however, your
staged changes are destroyed as part of the abort! Generally speaking,
the abort process assumes any changes in the index are part of the
operation to be aborted.

Add an earlier check in the cherry-pick sequence process to ensure that
the index is clean, reusing the already-generalized method used for
rebase. Also add a test.

Signed-off-by: Tao Klerks <[email protected]>

Author: TaoK

builtin/revert.c

@@ -224,7 +224,7 @@ static int run_sequencer(int argc, const char **argv, const char *prefix,
 		return sequencer_rollback(the_repository, opts);
 	if (cmd == 's')
 		return sequencer_skip(the_repository, opts);
-	return sequencer_pick_revisions(the_repository, opts);
+	return sequencer_pick_revisions(the_repository, opts, me);
 }
 
 int cmd_revert(int argc, const char **argv, const char *prefix)

sequencer.c

@@ -5169,7 +5169,8 @@ static int single_pick(struct repository *r,
 }
 
 int sequencer_pick_revisions(struct repository *r,
-			     struct replay_opts *opts)
+			     struct replay_opts *opts,
+			     char *me)
 {
 	struct todo_list todo_list = TODO_LIST_INIT;
 	struct object_id oid;
@@ -5223,10 +5224,13 @@ int sequencer_pick_revisions(struct repository *r,
 
 	/*
 	 * Start a new cherry-pick/ revert sequence; but
-	 * first, make sure that an existing one isn't in
-	 * progress
+	 * first, make sure that the index is clean and that
+	 * an existing one isn't in progress.
 	 */
 
+	if (require_clean_work_tree(the_repository, me,
+				    _("Please commit or stash them."), 1, 1))
+		return -1;
 	if (walk_revs_populate_todo(&todo_list, opts) ||
 			create_seq_dir(r) < 0)
 		return -1;

sequencer.h

@@ -159,7 +159,8 @@ void todo_list_filter_update_refs(struct repository *r,
 /* Call this to setup defaults before parsing command line options */
 void sequencer_init_config(struct replay_opts *opts);
 int sequencer_pick_revisions(struct repository *repo,
-			     struct replay_opts *opts);
+			     struct replay_opts *opts,
+			     char *me);
 int sequencer_continue(struct repository *repo, struct replay_opts *opts);
 int sequencer_rollback(struct repository *repo, struct replay_opts *opts);
 int sequencer_skip(struct repository *repo, struct replay_opts *opts);

t/t3510-cherry-pick-sequence.sh

@@ -47,6 +47,16 @@ test_expect_success 'cherry-pick persists data on failure' '
 	test_path_is_file .git/sequencer/opts
 '
 
+test_expect_success 'cherry-pick sequence refuses to run on dirty index' '
+	pristine_detach initial &&
+	touch localindexchange &&
+	git add localindexchange &&
+	echo picking &&
+	test_must_fail git cherry-pick initial..picked &&
+	test_path_is_missing .git/sequencer &&
+	test_must_fail git cherry-pick --abort
+'
+
 test_expect_success 'cherry-pick mid-cherry-pick-sequence' '
 	pristine_detach initial &&
 	test_must_fail git cherry-pick base..anotherpick &&