diff --git a/lib/util/host-rules.ts b/lib/util/host-rules.ts
index e31d95016847843a750d15697d27d341803dc22d..c2e1225166dbff61f908c47c5c334639bb3b5c50 100644
--- a/lib/util/host-rules.ts
+++ b/lib/util/host-rules.ts
@@ -82,7 +82,7 @@ function matchesBaseUrl(rule: HostRule, search: HostRuleSearch) {
 export function find(search: HostRuleSearch) {
   if (!(search.hostType || search.url)) {
     logger.warn({ search }, 'Invalid hostRules search');
-    return null;
+    return {};
   }
   let res = ({} as any) as HostRule;
   // First, apply empty rule matches
diff --git a/test/util/host-rules.spec.js b/test/util/host-rules.spec.js
index 8d105b9dc472935ed5182846370f638395ea9703..260d45c1cfc03ca69f8958a584724209c93da7ac 100644
--- a/test/util/host-rules.spec.js
+++ b/test/util/host-rules.spec.js
@@ -42,8 +42,8 @@ describe('util/host-rules', () => {
     });
   });
   describe('find()', () => {
-    it('warns and returns null for bad search', () => {
-      expect(find({ abc: 'def' })).toBeNull();
+    it('warns and returns empty for bad search', () => {
+      expect(find({ abc: 'def' })).toEqual({});
     });
     it('needs exact host matches', () => {
       add({