builtin rebase: fast-forward to onto if it is a proper descendant

When trying to rebase onto a direct descendant of HEAD, we can take a shortcut and fast-forward instead. This commit makes it so. Signed-off-by: Pratik Karki <predatoramigo@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Pratik Karki committed Aug 8, 2018 at 21:21 UTC 7eecfa56017017208fd71c7aad9310a582a558ad
1 file changed +18
builtin/rebase.c
+18
@@ -1368,6 +1368,24 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
1368 die(_("Could not detach HEAD"));
1369 strbuf_release(&msg);
1370
1371 + /*
1372 + * If the onto is a proper descendant of the tip of the branch, then
1373 + * we just fast-forwarded.
1374 + */
1375 + strbuf_reset(&msg);
1376 + if (!oidcmp(&merge_base, &options.orig_head)) {
1377 + printf(_("Fast-forwarded %s to %s. \n"),
1378 + branch_name, options.onto_name);
1379 + strbuf_addf(&msg, "rebase finished: %s onto %s",
1380 + options.head_name ? options.head_name : "detached HEAD",
1381 + oid_to_hex(&options.onto->object.oid));
1382 + reset_head(NULL, "Fast-forwarded", options.head_name, 0,
1383 + "HEAD", msg.buf);
1384 + strbuf_release(&msg);
1385 + ret = !!finish_rebase(&options);
1386 + goto cleanup;
1387 + }
1388 +
1389 strbuf_addf(&revisions, "%s..%s",
1390 options.root ? oid_to_hex(&options.onto->object.oid) :
1391 (options.restrict_revision ?