sequencer: tolerate abbreviated stopped-sha file

In 0512eab ("sequencer: stop abbreviating stopped-sha file",
2020-09-25), Git was taught both to write full object names to the
stopped-sha file and to require full object names when reading. However,
a user would experience a problem if they started an interactive rebase
using an old version of Git and then continued with a current version of
Git (for example, if the system version of Git was updated in the
meantime).

Teach Git to allow object names of any length when reading.

Signed-off-by: Jonathan Tan <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: jonathantanmy

sequencer.c

@@ -2552,7 +2552,7 @@ static int read_populate_opts(struct replay_opts *opts)
 		}
 
 		if (read_oneliner(&buf, rebase_path_squash_onto(), 0)) {
-			if (get_oid_hex(buf.buf, &opts->squash_onto) < 0) {
+			if (get_oid_committish(buf.buf, &opts->squash_onto) < 0) {
 				ret = error(_("unusable squash-onto"));
 				goto done_rebase_i;
 			}