do not refetch license if signature header absents from a response (#…

…79645)

Co-authored-by: Kibana Machine <[email protected]>

x-pack/plugins/licensing/public/plugin.test.ts

@@ -240,6 +240,46 @@ describe('licensing plugin', () => {
       expect(coreSetup.http.get).toHaveBeenCalledTimes(1);
     });
 
+    it('http interceptor does not trigger re-fetch if signature header is not present', async () => {
+      const sessionStorage = coreMock.createStorage();
+      plugin = new LicensingPlugin(coreMock.createPluginInitializerContext(), sessionStorage);
+
+      const coreSetup = coreMock.createSetup();
+
+      coreSetup.http.get.mockResolvedValue(licenseMock.createLicense({ signature: 'signature-1' }));
+
+      let registeredInterceptor: HttpInterceptor;
+      coreSetup.http.intercept.mockImplementation((interceptor: HttpInterceptor) => {
+        registeredInterceptor = interceptor;
+        return () => undefined;
+      });
+
+      await plugin.setup(coreSetup);
+      await plugin.start(coreStart);
+      expect(registeredInterceptor!.response).toBeDefined();
+
+      const httpResponse = {
+        response: {
+          headers: {
+            get(name: string) {
+              if (name === 'kbn-license-sig') {
+                return undefined;
+              }
+              throw new Error('unexpected header');
+            },
+          },
+        },
+        request: {
+          url: 'http://10.10.10.10:5601/api/hello',
+        },
+      };
+      expect(coreSetup.http.get).toHaveBeenCalledTimes(0);
+
+      await registeredInterceptor!.response!(httpResponse as any, null as any);
+
+      expect(coreSetup.http.get).toHaveBeenCalledTimes(0);
+    });
+
     it('http interceptor does not trigger license re-fetch for anonymous pages', async () => {
       const sessionStorage = coreMock.createStorage();
       plugin = new LicensingPlugin(coreMock.createPluginInitializerContext(), sessionStorage);

x-pack/plugins/licensing/public/plugin.ts

@@ -101,7 +101,7 @@ export class LicensingPlugin implements Plugin<LicensingPluginSetup, LicensingPl
         if (core.http.anonymousPaths.isAnonymous(window.location.pathname)) return httpResponse;
         if (httpResponse.response) {
           const signatureHeader = httpResponse.response.headers.get('kbn-license-sig');
-          if (this.prevSignature !== signatureHeader) {
+          if (typeof signatureHeader === 'string' && this.prevSignature !== signatureHeader) {
             if (!httpResponse.request!.url.includes(this.infoEndpoint)) {
               signatureUpdated$.next();
             }