Merge pull request #40 from goccy/feature/fix-anonymous-struct

Fix anonymous struct fields

Author: goccy

encode_compile.go

@@ -622,7 +622,6 @@ type structFieldPair struct {
 }
 
 func (e *Encoder) anonymousStructFieldPairMap(typ *rtype, tags structTags, valueCode *structFieldCode) map[string][]structFieldPair {
-	//fmt.Println("type = ", typ, "valueCode = ", valueCode.dump())
 	anonymousFields := map[string][]structFieldPair{}
 	f := valueCode
 	var prevAnonymousField *structFieldCode

encode_opcode.go

@@ -112,15 +112,24 @@ func (c *opcode) dump() string {
 	codes := []string{}
 	for code := c; code.op != opEnd; {
 		indent := strings.Repeat(" ", code.indent)
-		codes = append(codes, fmt.Sprintf("%s%s ( %p )", indent, code.op, unsafe.Pointer(code)))
 		switch code.op.codeType() {
 		case codeArrayElem:
+			codes = append(codes, fmt.Sprintf("%s%s ( %p )", indent, code.op, unsafe.Pointer(code)))
 			code = code.toArrayElemCode().end
 		case codeSliceElem:
+			codes = append(codes, fmt.Sprintf("%s%s ( %p )", indent, code.op, unsafe.Pointer(code)))
 			code = code.toSliceElemCode().end
 		case codeMapKey:
+			codes = append(codes, fmt.Sprintf("%s%s ( %p )", indent, code.op, unsafe.Pointer(code)))
 			code = code.toMapKeyCode().end
+		case codeStructField:
+			sf := code.toStructFieldCode()
+			key := sf.displayKey
+			offset := sf.offset
+			codes = append(codes, fmt.Sprintf("%s%s [%s:%d] ( %p )", indent, code.op, key, offset, unsafe.Pointer(code)))
+			code = code.next
 		default:
+			codes = append(codes, fmt.Sprintf("%s%s ( %p )", indent, code.op, unsafe.Pointer(code)))
 			code = code.next
 		}
 	}

encode_test.go

@@ -1392,3 +1392,180 @@ func TestDuplicatedFieldDisappears(t *testing.T) {
 		t.Fatalf("Marshal: got %s want %s", got, want)
 	}
 }
+
+func TestAnonymousFields(t *testing.T) {
+	tests := []struct {
+		label     string             // Test name
+		makeInput func() interface{} // Function to create input value
+		want      string             // Expected JSON output
+	}{{
+		// Both S1 and S2 have a field named X. From the perspective of S,
+		// it is ambiguous which one X refers to.
+		// This should not serialize either field.
+		label: "AmbiguousField",
+		makeInput: func() interface{} {
+			type (
+				S1 struct{ x, X int }
+				S2 struct{ x, X int }
+				S  struct {
+					S1
+					S2
+				}
+			)
+			return S{S1{1, 2}, S2{3, 4}}
+		},
+		want: `{}`,
+	}, {
+		label: "DominantField",
+		// Both S1 and S2 have a field named X, but since S has an X field as
+		// well, it takes precedence over S1.X and S2.X.
+		makeInput: func() interface{} {
+			type (
+				S1 struct{ x, X int }
+				S2 struct{ x, X int }
+				S  struct {
+					S1
+					S2
+					x, X int
+				}
+			)
+			return S{S1{1, 2}, S2{3, 4}, 5, 6}
+		},
+		want: `{"X":6}`,
+	}, {
+		// Unexported embedded field of non-struct type should not be serialized.
+		label: "UnexportedEmbeddedInt",
+		makeInput: func() interface{} {
+			type (
+				myInt int
+				S     struct{ myInt }
+			)
+			return S{5}
+		},
+		want: `{}`,
+	}, {
+		// Exported embedded field of non-struct type should be serialized.
+		label: "ExportedEmbeddedInt",
+		makeInput: func() interface{} {
+			type (
+				MyInt int
+				S     struct{ MyInt }
+			)
+			return S{5}
+		},
+		want: `{"MyInt":5}`,
+	}, {
+		// Unexported embedded field of pointer to non-struct type
+		// should not be serialized.
+		label: "UnexportedEmbeddedIntPointer",
+		makeInput: func() interface{} {
+			type (
+				myInt int
+				S     struct{ *myInt }
+			)
+			s := S{new(myInt)}
+			*s.myInt = 5
+			return s
+		},
+		want: `{}`,
+	}, {
+		// Exported embedded field of pointer to non-struct type
+		// should be serialized.
+		label: "ExportedEmbeddedIntPointer",
+		makeInput: func() interface{} {
+			type (
+				MyInt int
+				S     struct{ *MyInt }
+			)
+			s := S{new(MyInt)}
+			*s.MyInt = 5
+			return s
+		},
+		want: `{"MyInt":5}`,
+	}, {
+		// Exported fields of embedded structs should have their
+		// exported fields be serialized regardless of whether the struct types
+		// themselves are exported.
+		label: "EmbeddedStruct",
+		makeInput: func() interface{} {
+			type (
+				s1 struct{ x, X int }
+				S2 struct{ y, Y int }
+				S  struct {
+					s1
+					S2
+				}
+			)
+			return S{s1{1, 2}, S2{3, 4}}
+		},
+		want: `{"X":2,"Y":4}`,
+	}, {
+		// Exported fields of pointers to embedded structs should have their
+		// exported fields be serialized regardless of whether the struct types
+		// themselves are exported.
+		label: "EmbeddedStructPointer",
+		makeInput: func() interface{} {
+			type (
+				s1 struct{ x, X int }
+				S2 struct{ y, Y int }
+				S  struct {
+					*s1
+					*S2
+				}
+			)
+			return S{&s1{1, 2}, &S2{3, 4}}
+		},
+		want: `{"X":2,"Y":4}`,
+	}, {
+		// Exported fields on embedded unexported structs at multiple levels
+		// of nesting should still be serialized.
+		label: "NestedStructAndInts",
+		makeInput: func() interface{} {
+			type (
+				MyInt1 int
+				MyInt2 int
+				myInt  int
+				s2     struct {
+					MyInt2
+					myInt
+				}
+				s1 struct {
+					MyInt1
+					myInt
+					s2
+				}
+				S struct {
+					s1
+					myInt
+				}
+			)
+			return S{s1{1, 2, s2{3, 4}}, 6}
+		},
+		want: `{"MyInt1":1,"MyInt2":3}`,
+	}, {
+		// If an anonymous struct pointer field is nil, we should ignore
+		// the embedded fields behind it. Not properly doing so may
+		// result in the wrong output or reflect panics.
+		label: "EmbeddedFieldBehindNilPointer",
+		makeInput: func() interface{} {
+			type (
+				S2 struct{ Field string }
+				S  struct{ *S2 }
+			)
+			return S{}
+		},
+		want: `{}`,
+	}}
+
+	for i, tt := range tests {
+		t.Run(tt.label, func(t *testing.T) {
+			b, err := json.Marshal(tt.makeInput())
+			if err != nil {
+				t.Fatalf("%d: Marshal() = %v, want nil error", i, err)
+			}
+			if string(b) != tt.want {
+				t.Fatalf("%d: Marshal() = %q, want %q", i, b, tt.want)
+			}
+		})
+	}
+}