Updated options.go

1. Added one more check for deprecated clientOption FallbackHostsUseDefault
2. Moved fallbackHostUseDefault endpoint integration test to unit test
3. Fixed rest_client_integration tests RSC15 fallbacks

Author: sacOO7

ably/export_test.go

@@ -24,6 +24,10 @@ func (opts *clientOptions) GetRealtimeHost() string {
 	return opts.getRealtimeHost()
 }
 
+func (opts *clientOptions) Validate() error {
+	return opts.validate()
+}
+
 func (opts *clientOptions) GetHostnameFromEndpoint() string {
 	return opts.getHostnameFromEndpoint()
 }

ably/options.go

@@ -428,8 +428,8 @@ type clientOptions struct {
 }
 
 func (opts *clientOptions) validate() error {
-	if !empty(opts.Endpoint) && (!empty(opts.Environment) || !empty(opts.RealtimeHost) || !empty(opts.RESTHost)) {
-		err := errors.New("invalid client option: cannot use endpoint with any of environment, realtimeHost or restHost")
+	if !empty(opts.Endpoint) && (!empty(opts.Environment) || !empty(opts.RealtimeHost) || !empty(opts.RESTHost) || opts.FallbackHostsUseDefault) {
+		err := errors.New("invalid client option: cannot use endpoint with any of deprecated options environment, realtimeHost, restHost or FallbackHostsUseDefault")
 		logger := opts.LogHandler
 		logger.Printf(LogError, "Invalid client options : %v", err.Error())
 		return err

ably/options_test.go

@@ -160,22 +160,6 @@ func TestHosts_REC1(t *testing.T) {
 			assert.Equal(t, ably.DefaultFallbackHosts(), fallbackHosts)
 		})
 
-		// Fallbacks will be null since ports are not default
-		// t.Run("REC1c with legacy custom environment and non default ports", func(t *testing.T) {
-		// 	clientOptions := ably.NewClientOptions(
-		// 		ably.WithEnvironment("local"),
-		// 		ably.WithPort(8080),
-		// 		ably.WithTLSPort(8081),
-		// 	)
-		// 	assert.Equal(t, "local.realtime.ably.net", clientOptions.GetRestHost())
-		// 	assert.False(t, clientOptions.NoTLS)
-		// 	port, isDefaultPort := clientOptions.ActivePort()
-		// 	assert.Equal(t, 8081, port)
-		// 	assert.False(t, isDefaultPort)
-		// 	fallbackHosts, _ := clientOptions.GetFallbackHosts()
-		// 	assert.Equal(t, ably.GetEndpointFallbackHosts("local"), fallbackHosts)
-		// })
-
 		t.Run("REC1d1 with custom restHost", func(t *testing.T) {
 			clientOptions := ably.NewClientOptions(ably.WithRESTHost("test.org"))
 			assert.Equal(t, "test.org", clientOptions.GetRestHost())
@@ -224,6 +208,15 @@ func TestHosts_REC1(t *testing.T) {
 		})
 	})
 
+	t.Run("If endpoint option is used with deprecated fallbackHostUseDefault, throw error", func(t *testing.T) {
+		clientOptions := ably.NewClientOptions(
+			ably.WithFallbackHostsUseDefault(true),
+			ably.WithEndpoint("custom"))
+		err := clientOptions.Validate()
+		assert.Equal(t, err.Error(),
+			"invalid client option: cannot use endpoint with any of deprecated options environment, realtimeHost, restHost or FallbackHostsUseDefault")
+	})
+
 	t.Run("REC2a with fallbackHosts", func(t *testing.T) {
 		clientOptions := ably.NewClientOptions(ably.WithFallbackHosts([]string{"a.example.com", "b.example.com"}))
 		assert.Equal(t, "main.realtime.ably.net", clientOptions.GetRestHost())

ably/realtime_client_integration_test.go

@@ -309,20 +309,6 @@ func TestRealtime_RTN17_HostFallback(t *testing.T) {
 			assert.ElementsMatch(t, fallbacks, visitedHosts[1:])
 		})
 
-		t.Run("apply when fallbackHostUseDefault is true, even if endpoint option is used", func(t *testing.T) {
-			visitedHosts := initClientWithConnError(
-				getTimeoutErr(),
-				ably.WithFallbackHostsUseDefault(true),
-				ably.WithEndpoint("custom"))
-
-			expectedPrimaryHost := "custom.realtime.ably.net"
-			expectedFallbackHosts := ably.DefaultFallbackHosts()
-
-			assert.Equal(t, 6, len(visitedHosts))
-			assert.Equal(t, expectedPrimaryHost, visitedHosts[0])
-			assert.ElementsMatch(t, expectedFallbackHosts, visitedHosts[1:])
-		})
-
 		t.Run("apply when fallbackHostUseDefault is true, even if legacy realtimeHost is set", func(t *testing.T) {
 			visitedHosts := initClientWithConnError(
 				getTimeoutErr(),
@@ -380,7 +366,7 @@ func TestRealtime_RTN17_HostFallback(t *testing.T) {
 			t.Fatalf("Error connecting host with error %v", err)
 		}
 		realtimeSuccessHost := realtimeMsgRecorder.URLs()[0].Hostname()
-		fallbackHosts := ably.GetEndpointFallbackHosts("sandbox")
+		fallbackHosts := ably.GetEndpointFallbackHosts("nonprod:sandbox")
 		if !ablyutil.SliceContains(fallbackHosts, realtimeSuccessHost) {
 			t.Fatalf("realtime host must be one of fallback hosts, received %v", realtimeSuccessHost)
 		}

ably/rest_client_integration_test.go

@@ -347,10 +347,10 @@ func TestRest_RSC15_HostFallback(t *testing.T) {
 			ably.WithUseTokenAuth(true),
 		}
 		retryCount, hosts := runTestServer(t, options)
-		assert.Equal(t, 6, retryCount)                          // 1 primary and 5 default fallback hosts
-		assert.Equal(t, "main.realtime.ably.net", hosts[0])     // primary host
-		assertSubset(t, ably.DefaultFallbackHosts(), hosts[1:]) // remaining fallback hosts
-		assertUnique(t, hosts)                                  // ensure all picked fallbacks are unique
+		assert.Equal(t, 6, retryCount)                                 // 1 primary and 5 default fallback hosts
+		assert.Equal(t, "sandbox.realtime.ably-nonprod.net", hosts[0]) // primary host
+		assertSubset(t, ably.DefaultFallbackHosts(), hosts[1:])        // remaining fallback hosts
+		assertUnique(t, hosts)                                         // ensure all picked fallbacks are unique
 	})
 
 	runTestServerWithRequestTimeout := func(t *testing.T, options []ably.ClientOption) (int, []string) {
@@ -393,10 +393,10 @@ func TestRest_RSC15_HostFallback(t *testing.T) {
 			ably.WithUseTokenAuth(true),
 		}
 		retryCount, hosts := runTestServerWithRequestTimeout(t, options)
-		assert.Equal(t, 6, retryCount)                          // 1 primary and 5 default fallback hosts
-		assert.Equal(t, "main.realtime.ably.net", hosts[0])     // primary host
-		assertSubset(t, ably.DefaultFallbackHosts(), hosts[1:]) // remaining fallback hosts
-		assertUnique(t, hosts)                                  // ensure all picked fallbacks are unique
+		assert.Equal(t, 6, retryCount)                                 // 1 primary and 5 default fallback hosts
+		assert.Equal(t, "sandbox.realtime.ably-nonprod.net", hosts[0]) // primary host
+		assertSubset(t, ably.DefaultFallbackHosts(), hosts[1:])        // remaining fallback hosts
+		assertUnique(t, hosts)                                         // ensure all picked fallbacks are unique
 	})
 
 	t.Run("RSC15l1 must use alternative host on host unresolvable or unreachable", func(t *testing.T) {