builtin rebase: support `git rebase <upstream> <switch-to>`

This commit adds support for `switch-to` which is used to switch to the target branch if needed. The equivalent codes found in shell script `git-legacy-rebase.sh` is converted to builtin `rebase.c`. Signed-off-by: Pratik Karki <predatoramigo@gmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Pratik Karki committed Sep 4, 2018 at 14:27 UTC e65123a71d0ca134f901e2340674a712e70ce023
1 file changed +44 -4
builtin/rebase.c
+44 -4
@@ -79,6 +79,7 @@ struct rebase_options {
79 struct commit *onto;
80 const char *onto_name;
81 const char *revisions;
82 + const char *switch_to;
83 int root;
84 struct commit *restrict_revision;
85 int dont_finish_rebase;
@@ -186,6 +187,8 @@ static int run_specific_rebase(struct rebase_options *opts)
187 opts->flags & REBASE_DIFFSTAT ? "t" : "");
188 add_var(&script_snippet, "force_rebase",
189 opts->flags & REBASE_FORCE ? "t" : "");
190 + if (opts->switch_to)
191 + add_var(&script_snippet, "switch_to", opts->switch_to);
192
193 switch (opts->type) {
194 case REBASE_AM:
@@ -564,9 +567,23 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
567 * orig_head -- commit object name of tip of the branch before rebasing
568 * head_name -- refs/heads/<that-branch> or NULL (detached HEAD)
569 */
567 - if (argc > 0)
568 - die("TODO: handle switch_to");
569 - else {
570 + if (argc == 1) {
571 + /* Is it "rebase other branchname" or "rebase other commit"? */
572 + branch_name = argv[0];
573 + options.switch_to = argv[0];
574 +
575 + /* Is it a local branch? */
576 + strbuf_reset(&buf);
577 + strbuf_addf(&buf, "refs/heads/%s", branch_name);
578 + if (!read_ref(buf.buf, &options.orig_head))
579 + options.head_name = xstrdup(buf.buf);
580 + /* If not is it a valid ref (branch or commit)? */
581 + else if (!get_oid(branch_name, &options.orig_head))
582 + options.head_name = NULL;
583 + else
584 + die(_("fatal: no such branch/commit '%s'"),
585 + branch_name);
586 + } else if (argc == 0) {
587 /* Do not need to switch branches, we are already on it. */
588 options.head_name =
589 xstrdup_or_null(resolve_ref_unsafe("HEAD", 0, NULL,
@@ -585,7 +602,8 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
602 }
603 if (get_oid("HEAD", &options.orig_head))
604 die(_("Could not resolve HEAD to a revision"));
588 - }
605 + } else
606 + BUG("unexpected number of arguments left to parse");
607
608 if (read_index(the_repository->index) < 0)
609 die(_("could not read index"));
@@ -612,6 +630,28 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
630 int flag;
631
632 if (!(options.flags & REBASE_FORCE)) {
633 + /* Lazily switch to the target branch if needed... */
634 + if (options.switch_to) {
635 + struct object_id oid;
636 +
637 + if (get_oid(options.switch_to, &oid) < 0) {
638 + ret = !!error(_("could not parse '%s'"),
639 + options.switch_to);
640 + goto cleanup;
641 + }
642 +
643 + strbuf_reset(&buf);
644 + strbuf_addf(&buf, "rebase: checkout %s",
645 + options.switch_to);
646 + if (reset_head(&oid, "checkout",
647 + options.head_name, 0) < 0) {
648 + ret = !!error(_("could not switch to "
649 + "%s"),
650 + options.switch_to);
651 + goto cleanup;
652 + }
653 + }
654 +
655 if (!(options.flags & REBASE_NO_QUIET))
656 ; /* be quiet */
657 else if (!strcmp(branch_name, "HEAD") &&