From 83cedbec8582347a12b4233a34b269eebab3b0e6 Mon Sep 17 00:00:00 2001
From: Colin Cross <ccross@android.com>
Date: Fri, 20 Nov 2015 17:01:25 -0800
Subject: [PATCH] Fix ZeroProperties bug on nested interfaces

ZeroProperties was setting nested structs to their zero value, even if
they contained an interface that should be recursed into, not replaced
with nil.
---
 proptools/clone.go      |  5 ++-
 proptools/clone_test.go | 95 +++++++++++++++++++++++++++++++++++++++--
 2 files changed, 95 insertions(+), 5 deletions(-)

diff --git a/proptools/clone.go b/proptools/clone.go
index 7496584..3b23a57 100644
--- a/proptools/clone.go
+++ b/proptools/clone.go
@@ -140,7 +140,7 @@ func ZeroProperties(structValue reflect.Value) {
 		fieldValue := structValue.Field(i)
 
 		switch fieldValue.Kind() {
-		case reflect.Bool, reflect.String, reflect.Struct, reflect.Slice, reflect.Int, reflect.Uint:
+		case reflect.Bool, reflect.String, reflect.Slice, reflect.Int, reflect.Uint:
 			fieldValue.Set(reflect.Zero(fieldValue.Type()))
 		case reflect.Interface:
 			if fieldValue.IsNil() {
@@ -172,7 +172,8 @@ func ZeroProperties(structValue reflect.Value) {
 				panic(fmt.Errorf("can't zero field %q: points to a %s",
 					field.Name, fieldValue.Elem().Kind()))
 			}
-
+		case reflect.Struct:
+			ZeroProperties(fieldValue)
 		default:
 			panic(fmt.Errorf("unexpected kind for property struct field %q: %s",
 				field.Name, fieldValue.Kind()))
diff --git a/proptools/clone_test.go b/proptools/clone_test.go
index f7460cf..acbd50c 100644
--- a/proptools/clone_test.go
+++ b/proptools/clone_test.go
@@ -130,6 +130,26 @@ var clonePropertiesTestCases = []struct {
 		},
 	},
 	{
+		// Clone nested interface
+		in: &struct {
+			Nested struct{ S interface{} }
+		}{
+			Nested: struct{ S interface{} }{
+				S: &struct{ S string }{
+					S: "string1",
+				},
+			},
+		},
+		out: &struct {
+			Nested struct{ S interface{} }
+		}{
+			Nested: struct{ S interface{} }{
+				S: &struct{ S string }{
+					S: "string1",
+				},
+			},
+		},
+	}, {
 		// Empty struct
 		in:  &struct{}{},
 		out: &struct{}{},
@@ -267,6 +287,25 @@ var cloneEmptyPropertiesTestCases = []struct {
 			S: &struct{ S string }{},
 		},
 	},
+	{
+		// Clone nested interface
+		in: &struct {
+			Nested struct{ S interface{} }
+		}{
+			Nested: struct{ S interface{} }{
+				S: &struct{ S string }{
+					S: "string1",
+				},
+			},
+		},
+		out: &struct {
+			Nested struct{ S interface{} }
+		}{
+			Nested: struct{ S interface{} }{
+				S: &struct{ S string }{},
+			},
+		},
+	},
 	{
 		// Empty struct
 		in:  &struct{}{},
@@ -295,11 +334,61 @@ var cloneEmptyPropertiesTestCases = []struct {
 		},
 		out: &struct{ S *struct{} }{},
 	},
+	{
+		// Anonymous struct
+		in: &struct {
+			EmbeddedStruct
+			Nested struct{ EmbeddedStruct }
+		}{
+			EmbeddedStruct: EmbeddedStruct{
+				S: "string1",
+			},
+			Nested: struct{ EmbeddedStruct }{
+				EmbeddedStruct: EmbeddedStruct{
+					S: "string2",
+				},
+			},
+		},
+		out: &struct {
+			EmbeddedStruct
+			Nested struct{ EmbeddedStruct }
+		}{
+			EmbeddedStruct: EmbeddedStruct{},
+			Nested: struct{ EmbeddedStruct }{
+				EmbeddedStruct: EmbeddedStruct{},
+			},
+		},
+	},
+	{
+		// Anonymous interface
+		in: &struct {
+			EmbeddedInterface
+			Nested struct{ EmbeddedInterface }
+		}{
+			EmbeddedInterface: &struct{ S string }{
+				S: "string1",
+			},
+			Nested: struct{ EmbeddedInterface }{
+				EmbeddedInterface: &struct{ S string }{
+					S: "string2",
+				},
+			},
+		},
+		out: &struct {
+			EmbeddedInterface
+			Nested struct{ EmbeddedInterface }
+		}{
+			EmbeddedInterface: &struct{ S string }{},
+			Nested: struct{ EmbeddedInterface }{
+				EmbeddedInterface: &struct{ S string }{},
+			},
+		},
+	},
 }
 
 func TestCloneEmptyProperties(t *testing.T) {
 	for _, testCase := range cloneEmptyPropertiesTestCases {
-		testString := fmt.Sprintf("%s", testCase.in)
+		testString := fmt.Sprintf("%#v", testCase.in)
 
 		got := CloneEmptyProperties(reflect.ValueOf(testCase.in).Elem()).Interface()
 
@@ -314,9 +403,9 @@ func TestCloneEmptyProperties(t *testing.T) {
 
 func TestZeroProperties(t *testing.T) {
 	for _, testCase := range cloneEmptyPropertiesTestCases {
-		testString := fmt.Sprintf("%s", testCase.in)
+		testString := fmt.Sprintf("%#v", testCase.in)
 
-		got := CloneEmptyProperties(reflect.ValueOf(testCase.in).Elem()).Interface()
+		got := CloneProperties(reflect.ValueOf(testCase.in).Elem()).Interface()
 		ZeroProperties(reflect.ValueOf(got).Elem())
 
 		if !reflect.DeepEqual(testCase.out, got) {
-- 
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