Merge pull request #38666 from tanshanshan/empty-check

Automatic merge from submit-queue (batch tested with PRs 39475, 38666, 39327, 38396, 39613)

Add checking the nil value 

**What this PR does / why we need it**:

Add checking the nil value.

Thanks.

**Special notes for your reviewer**:

cmd/kube-aggregator/pkg/client/clientset_generated/clientset/clientset.go

@@ -58,6 +58,9 @@ func (c *Clientset) Apiregistration() v1alpha1apiregistration.ApiregistrationV1a
 
 // Discovery retrieves the DiscoveryClient
 func (c *Clientset) Discovery() discovery.DiscoveryInterface {
+	if c == nil {
+		return nil
+	}
 	return c.DiscoveryClient
 }
 

cmd/kube-aggregator/pkg/client/clientset_generated/internalclientset/clientset.go

@@ -47,6 +47,9 @@ func (c *Clientset) Apiregistration() internalversionapiregistration.Apiregistra
 
 // Discovery retrieves the DiscoveryClient
 func (c *Clientset) Discovery() discovery.DiscoveryInterface {
+	if c == nil {
+		return nil
+	}
 	return c.DiscoveryClient
 }
 

cmd/libs/go2idl/client-gen/generators/generator_for_clientset.go

@@ -149,6 +149,9 @@ func (c *Clientset) $.Group$() $.PackageName$.$.GroupVersion$Interface {
 var getDiscoveryTemplate = `
 // Discovery retrieves the DiscoveryClient
 func (c *Clientset) Discovery() $.DiscoveryInterface|raw$ {
+	if c == nil {
+		return nil
+	}
 	return c.DiscoveryClient
 }
 `

cmd/libs/go2idl/client-gen/testoutput/clientset_generated/test_internalclientset/clientset.go

@@ -47,6 +47,9 @@ func (c *Clientset) Testgroup() internalversiontestgroup.TestgroupInterface {
 
 // Discovery retrieves the DiscoveryClient
 func (c *Clientset) Discovery() discovery.DiscoveryInterface {
+	if c == nil {
+		return nil
+	}
 	return c.DiscoveryClient
 }
 

federation/client/clientset_generated/federation_clientset/clientset.go

@@ -124,6 +124,9 @@ func (c *Clientset) Federation() v1beta1federation.FederationV1beta1Interface {
 
 // Discovery retrieves the DiscoveryClient
 func (c *Clientset) Discovery() discovery.DiscoveryInterface {
+	if c == nil {
+		return nil
+	}
 	return c.DiscoveryClient
 }
 

federation/client/clientset_generated/federation_internalclientset/clientset.go

@@ -83,6 +83,9 @@ func (c *Clientset) Federation() internalversionfederation.FederationInterface {
 
 // Discovery retrieves the DiscoveryClient
 func (c *Clientset) Discovery() discovery.DiscoveryInterface {
+	if c == nil {
+		return nil
+	}
 	return c.DiscoveryClient
 }
 

pkg/client/clientset_generated/clientset/clientset.go

@@ -290,6 +290,9 @@ func (c *Clientset) Storage() v1beta1storage.StorageV1beta1Interface {
 
 // Discovery retrieves the DiscoveryClient
 func (c *Clientset) Discovery() discovery.DiscoveryInterface {
+	if c == nil {
+		return nil
+	}
 	return c.DiscoveryClient
 }
 

pkg/client/clientset_generated/internalclientset/clientset.go

@@ -167,6 +167,9 @@ func (c *Clientset) Storage() internalversionstorage.StorageInterface {
 
 // Discovery retrieves the DiscoveryClient
 func (c *Clientset) Discovery() discovery.DiscoveryInterface {
+	if c == nil {
+		return nil
+	}
 	return c.DiscoveryClient
 }