Assign Reference ID if no Potential Rules run (CO-2127)

app/src/Lib/Match/MatchService.php

@@ -679,6 +679,17 @@ public function searchReferenceId(string $sor, string $sorid, AttributeManager $
     // Next try potential matches
     $potentialMatches = $this->search(ConfidenceModeEnum::Potential, $sor, $sorid, $attributes);
 
+    // The calling code generally checks to see if any rules successfully ran,
+    // since if there were no valid attributes or rules we treat that as an error.
+    // If no potential rules ran, we return the canonicalMatches result instead.
+    // (If no canonical rules ran, it doesn't matter which we return, but if at
+    // least one did, this is how we indicate at least something tried to happen.)
+    // See also CO-2127.
+
+    if(empty($potentialMatches->getSuccessfulRules())) {
+      return $canonicalMatches;
+    }
+
     return $potentialMatches;
   }