rebase --apply: remove duplicated code

Use move_to_original_branch() when reattaching HEAD after a fast-forward
rather than open coding a copy of that code. move_to_original_branch()
does not call reset_head() if head_name is NULL but there should be no
user visible changes even though we currently call reset_head() in that
case. The reason for this is that the reset_head() call does not add a
message to the reflog because we're not changing the commit that HEAD
points to and so lock_ref_for_update() elides the update. When head_name
is not NULL then reset_head() behaves like "git symbolic-ref" and so the
reflog is updated.

Note that the removal of "strbuf_release(&msg)" is safe as there is an
identical call just above this hunk which can be seen by viewing the
diff with -U6.

Signed-off-by: Phillip Wood <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: phillipwood

builtin/rebase.c

@@ -1811,19 +1811,10 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 	 * If the onto is a proper descendant of the tip of the branch, then
 	 * we just fast-forwarded.
 	 */
-	strbuf_reset(&msg);
 	if (oideq(&branch_base, &options.orig_head->object.oid)) {
 		printf(_("Fast-forwarded %s to %s.\n"),
 			branch_name, options.onto_name);
-		strbuf_addf(&msg, "rebase finished: %s onto %s",
-			options.head_name ? options.head_name : "detached HEAD",
-			oid_to_hex(&options.onto->object.oid));
-		memset(&ropts, 0, sizeof(ropts));
-		ropts.branch = options.head_name;
-		ropts.flags = RESET_HEAD_REFS_ONLY;
-		ropts.head_msg = msg.buf;
-		reset_head(the_repository, &ropts);
-		strbuf_release(&msg);
+		move_to_original_branch(&options);
 		ret = finish_rebase(&options);
 		goto cleanup;
 	}