Fix encoding struct with null ptr to embedded struct

When encoding struct with null pointer to embedded struct, encoder skips the embedded struct because it is unreachable and doesn't return any error. Fixed: #24
fxamacker · Nov 12, 2019 · 593ee34 · 593ee34
1 parent e9f5a7f
commit 593ee34
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Showing 2 changed files with 72 additions and 23 deletions.
diff --git a/encode.go b/encode.go
@@ -360,19 +360,28 @@ func encodeStruct(e *encodeState, v reflect.Value, opts EncOptions) (int, error)
 		if flds[i].ef == nil {
 			return 0, &UnsupportedTypeError{v.Type()}
 		}
-		fv, err := fieldByIndex(v, flds[i].idx)
-		if err != nil {
-			putEncodeState(kve)
-			return 0, err
+		fv := v
+		ignore := false
+		for k, n := range flds[i].idx {
+			if k > 0 {
+				if fv.Kind() == reflect.Ptr && fv.Type().Elem().Kind() == reflect.Struct {
+					if fv.IsNil() {
+						// Null pointer to embedded struct
+						ignore = true
+						break
+					}
+					fv = fv.Elem()
+				}
+			}
+			fv = fv.Field(n)
 		}
-		if !fv.IsValid() || (flds[i].omitempty && isEmptyValue(fv)) {
+		if ignore || (flds[i].omitempty && isEmptyValue(fv)) {
 			continue
 		}
 
 		kve.Write(flds[i].cborName)
 
-		_, err = flds[i].ef(kve, fv, opts)
-		if err != nil {
+		if _, err := flds[i].ef(kve, fv, opts); err != nil {
 			putEncodeState(kve)
 			return 0, err
 		}

diff --git a/encode_test.go b/encode_test.go
@@ -418,6 +418,27 @@ func encodeCborHeader(t byte, n uint64) []byte {
 	}
 }
 
+func testMarshal(t *testing.T, testCases []marshalTest) {
+	for _, tc := range testCases {
+		for _, value := range tc.values {
+			if _, err := cbor.Marshal(value, cbor.EncOptions{}); err != nil {
+				t.Errorf("Marshal(%v, cbor.EncOptions{}) returns error %v", value, err)
+			}
+			if b, err := cbor.Marshal(value, cbor.EncOptions{Canonical: true}); err != nil {
+				t.Errorf("Marshal(%v, cbor.EncOptions{Canonical: true}) returns error %v", value, err)
+			} else if !bytes.Equal(b, tc.cborData) {
+				t.Errorf("Marshal(%v, cbor.EncOptions{Canonical: true}) = 0x%0x, want 0x%0x", value, b, tc.cborData)
+			}
+		}
+		r := cbor.RawMessage(tc.cborData)
+		if b, err := cbor.Marshal(r, cbor.EncOptions{}); err != nil {
+			t.Errorf("Marshal(%v, cbor.EncOptions{}) returns error %v", r, err)
+		} else if !bytes.Equal(b, r) {
+			t.Errorf("Marshal(%v, cbor.EncOptions{}) returns %v, want %v", r, b, r)
+		}
+	}
+}
+
 func TestMarshalStruct(t *testing.T) {
 	v1 := outer{
 		IntField:          123,
@@ -534,24 +555,43 @@ func TestMarshalStructCanonical(t *testing.T) {
 	}
 }
 
-func testMarshal(t *testing.T, testCases []marshalTest) {
-	for _, tc := range testCases {
-		for _, value := range tc.values {
-			if _, err := cbor.Marshal(value, cbor.EncOptions{}); err != nil {
-				t.Errorf("Marshal(%v, cbor.EncOptions{}) returns error %v", value, err)
-			}
-			if b, err := cbor.Marshal(value, cbor.EncOptions{Canonical: true}); err != nil {
-				t.Errorf("Marshal(%v, cbor.EncOptions{Canonical: true}) returns error %v", value, err)
-			} else if !bytes.Equal(b, tc.cborData) {
-				t.Errorf("Marshal(%v, cbor.EncOptions{Canonical: true}) = 0x%0x, want 0x%0x", value, b, tc.cborData)
-			}
+func TestMarshalNullPointerToEmbeddedStruct(t *testing.T) {
+	type (
+		T1 struct {
+			N int
 		}
-		r := cbor.RawMessage(tc.cborData)
-		if b, err := cbor.Marshal(r, cbor.EncOptions{}); err != nil {
-			t.Errorf("Marshal(%v, cbor.EncOptions{}) returns error %v", r, err)
-		} else if !bytes.Equal(b, r) {
-			t.Errorf("Marshal(%v, cbor.EncOptions{}) returns %v, want %v", r, b, r)
+		T2 struct {
+			*T1
 		}
+	)
+	v := T2{}
+	wantCborData := []byte{0xa0} // {}
+	cborData, err := cbor.Marshal(v, cbor.EncOptions{})
+	if err != nil {
+		t.Fatalf("Marshal(%v) returns error %v", v, err)
+	}
+	if !bytes.Equal(wantCborData, cborData) {
+		t.Errorf("Marshal(%v) = 0x%0x, want 0x%0x", v, cborData, wantCborData)
+	}
+}
+
+func TestMarshalNullPointerToStruct(t *testing.T) {
+	type (
+		T1 struct {
+			N int
+		}
+		T2 struct {
+			T *T1
+		}
+	)
+	v := T2{}
+	wantCborData := []byte{0xa1, 0x61, 0x54, 0xf6} // {T: nil}
+	cborData, err := cbor.Marshal(v, cbor.EncOptions{})
+	if err != nil {
+		t.Fatalf("Marshal(%v) returns error %v", v, err)
+	}
+	if !bytes.Equal(wantCborData, cborData) {
+		t.Errorf("Marshal(%v) = 0x%0x, want 0x%0x", v, cborData, wantCborData)
 	}
 }