+ if (err) {
+ va_list ap;
+ va_start(ap, fmt);
+ strbuf_vaddf(err, fmt, ap);
+ va_end(ap);
+ }
+ return NULL;
+}
+
+const char *branch_get_upstream(struct branch *branch, struct strbuf *err)
+{
+ if (!branch)
+ return error_buf(err, _("HEAD does not point to a branch"));
+ if (!branch->merge || !branch->merge[0] || !branch->merge[0]->dst) {
+ if (!ref_exists(branch->refname))
+ return error_buf(err, _("no such branch: '%s'"),
+ branch->name);
+ if (!branch->merge)
+ return error_buf(err,
+ _("no upstream configured for branch '%s'"),
+ branch->name);
+ return error_buf(err,
+ _("upstream branch '%s' not stored as a remote-tracking branch"),
+ branch->merge[0]->src);
+ }
+