Properly handle nil interfaces in DeepCopy.

pkg/api/deep_copy_generated.go

@@ -736,6 +736,8 @@ func deepCopy_api_List(in List, out *List, c *conversion.Cloner) error {
 		for i := range in.Items {
 			if newVal, err := c.DeepCopy(in.Items[i]); err != nil {
 				return err
+			} else if newVal == nil {
+				out.Items[i] = nil
 			} else {
 				out.Items[i] = newVal.(runtime.Object)
 			}
@@ -758,11 +760,15 @@ func deepCopy_api_ListOptions(in ListOptions, out *ListOptions, c *conversion.Cl
 	}
 	if newVal, err := c.DeepCopy(in.LabelSelector); err != nil {
 		return err
+	} else if newVal == nil {
+		out.LabelSelector = nil
 	} else {
 		out.LabelSelector = newVal.(labels.Selector)
 	}
 	if newVal, err := c.DeepCopy(in.FieldSelector); err != nil {
 		return err
+	} else if newVal == nil {
+		out.FieldSelector = nil
 	} else {
 		out.FieldSelector = newVal.(fields.Selector)
 	}
@@ -2124,6 +2130,8 @@ func deepCopy_resource_Quantity(in resource.Quantity, out *resource.Quantity, c
 	if in.Amount != nil {
 		if newVal, err := c.DeepCopy(in.Amount); err != nil {
 			return err
+		} else if newVal == nil {
+			out.Amount = nil
 		} else {
 			out.Amount = newVal.(*inf.Dec)
 		}

pkg/api/v1/deep_copy_generated.go

@@ -31,6 +31,8 @@ func deepCopy_resource_Quantity(in resource.Quantity, out *resource.Quantity, c
 	if in.Amount != nil {
 		if newVal, err := c.DeepCopy(in.Amount); err != nil {
 			return err
+		} else if newVal == nil {
+			out.Amount = nil
 		} else {
 			out.Amount = newVal.(*inf.Dec)
 		}

pkg/conversion/cloner.go

@@ -117,6 +117,13 @@ func (c *Cloner) RegisterGeneratedDeepCopyFunc(deepCopyFunc interface{}) error {
 
 // DeepCopy will perform a deep copy of a given object.
 func (c *Cloner) DeepCopy(in interface{}) (interface{}, error) {
+	// Can be invalid if we run DeepCopy(X) where X is a nil interface type.
+	// For example, we get an invalid value when someone tries to deep-copy
+	// a nil labels.Selector.
+	// This does not occur if X is nil and is a pointer to a concrete type.
+	if in == nil {
+		return nil, nil
+	}
 	inValue := reflect.ValueOf(in)
 	outValue, err := c.deepCopy(inValue)
 	if err != nil {

pkg/runtime/deep_copy_generator.go

@@ -420,6 +420,8 @@ func (g *deepCopyGenerator) writeDeepCopyForPtr(b *buffer, inField reflect.Struc
 			ifStmt := fmt.Sprintf(ifFormat, inField.Name)
 			b.addLine(ifStmt, indent+1)
 			b.addLine("return err\n", indent+2)
+			b.addLine("} else if newVal == nil {\n", indent+1)
+			b.addLine(fmt.Sprintf("out.%s = nil\n", inField.Name), indent+2)
 			b.addLine("} else {\n", indent+1)
 			assignFormat := "out.%s = newVal.(%s)\n"
 			assignStmt := fmt.Sprintf(assignFormat, inField.Name, g.typeName(inField.Type))
@@ -467,6 +469,8 @@ func (g *deepCopyGenerator) writeDeepCopyForSlice(b *buffer, inField reflect.Str
 			ifStmt := fmt.Sprintf(ifFormat, inField.Name)
 			b.addLine(ifStmt, indent+2)
 			b.addLine("return err\n", indent+3)
+			b.addLine("} else if newVal == nil {\n", indent+2)
+			b.addLine(fmt.Sprintf("out.%s[i] = nil\n", inField.Name), indent+3)
 			b.addLine("} else {\n", indent+2)
 			assignFormat := "out.%s[i] = newVal.(%s)\n"
 			assignStmt := fmt.Sprintf(assignFormat, inField.Name, g.typeName(inField.Type.Elem()))
@@ -508,6 +512,8 @@ func (g *deepCopyGenerator) writeDeepCopyForStruct(b *buffer, inType reflect.Typ
 			ifStmt := fmt.Sprintf(ifFormat, inField.Name)
 			b.addLine(ifStmt, indent)
 			b.addLine("return err\n", indent+1)
+			b.addLine("} else if newVal == nil {\n", indent)
+			b.addLine(fmt.Sprintf("out.%s = nil\n", inField.Name), indent+1)
 			b.addLine("} else {\n", indent)
 			copyFormat := "out.%s = newVal.(%s)\n"
 			copyStmt := fmt.Sprintf(copyFormat, inField.Name, g.typeName(inField.Type))