Merge branch 'ah/rebase-keep-base-fix'

"git rebase --keep-base <upstream> <branch-to-rebase>" computed the
commit to rebase onto incorrectly, which has been corrected.

* ah/rebase-keep-base-fix:
  rebase: use correct base for --keep-base when a branch is given

1 files changed, 28 insertions, 27 deletions

diff --git a/builtin/rebase.c b/builtin/rebase.c
index 27fde7bf28..7f3bffc0a2 100644
--- a/builtin/rebase.c
+++ b/builtin/rebase.c
@@ -1583,33 +1583,6 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 		options.upstream_arg = "--root";
 	}
 
-	/* Make sure the branch to rebase onto is valid. */
-	if (keep_base) {
-		strbuf_reset(&buf);
-		strbuf_addstr(&buf, options.upstream_name);
-		strbuf_addstr(&buf, "...");
-		options.onto_name = xstrdup(buf.buf);
-	} else if (!options.onto_name)
-		options.onto_name = options.upstream_name;
-	if (strstr(options.onto_name, "...")) {
-		if (get_oid_mb(options.onto_name, &merge_base) < 0) {
-			if (keep_base)
-				die(_("'%s': need exactly one merge base with branch"),
-				    options.upstream_name);
-			else
-				die(_("'%s': need exactly one merge base"),
-				    options.onto_name);
-		}
-		options.onto = lookup_commit_or_die(&merge_base,
-						    options.onto_name);
-	} else {
-		options.onto =
-			lookup_commit_reference_by_name(options.onto_name);
-		if (!options.onto)
-			die(_("Does not point to a valid commit '%s'"),
-				options.onto_name);
-	}
-
 	/*
 	 * If the branch to rebase is given, that is the branch we will rebase
 	 * branch_name -- branch/commit being rebased, or
@@ -1659,6 +1632,34 @@ int cmd_rebase(int argc, const char **argv, const char *prefix)
 	} else
 		BUG("unexpected number of arguments left to parse");
 
+	/* Make sure the branch to rebase onto is valid. */
+	if (keep_base) {
+		strbuf_reset(&buf);
+		strbuf_addstr(&buf, options.upstream_name);
+		strbuf_addstr(&buf, "...");
+		strbuf_addstr(&buf, branch_name);
+		options.onto_name = xstrdup(buf.buf);
+	} else if (!options.onto_name)
+		options.onto_name = options.upstream_name;
+	if (strstr(options.onto_name, "...")) {
+		if (get_oid_mb(options.onto_name, &merge_base) < 0) {
+			if (keep_base)
+				die(_("'%s': need exactly one merge base with branch"),
+				    options.upstream_name);
+			else
+				die(_("'%s': need exactly one merge base"),
+				    options.onto_name);
+		}
+		options.onto = lookup_commit_or_die(&merge_base,
+						    options.onto_name);
+	} else {
+		options.onto =
+			lookup_commit_reference_by_name(options.onto_name);
+		if (!options.onto)
+			die(_("Does not point to a valid commit '%s'"),
+				options.onto_name);
+	}
+
 	if (options.fork_point > 0) {
 		struct commit *head =
 			lookup_commit_reference(the_repository,