Bugfix Cast nil field (#84)

Author: instabledesign

field.go

@@ -54,6 +54,9 @@ type Field struct {
 
 // String will return Field as string
 func (f *Field) String() string {
+	if f.Value == nil {
+		return "<nil>"
+	}
 	switch f.Type {
 	case SkipType:
 		return "<skipped>"
@@ -113,6 +116,9 @@ func (f *Field) MarshalJSON() ([]byte, error) {
 	if marshallable, ok := f.Value.(json.Marshaler); ok {
 		return marshallable.MarshalJSON()
 	}
+	if f.Type == ErrorType && f.Value == nil {
+		return []byte("null"), nil
+	}
 	switch f.Type {
 	case BoolType, Int8Type, Int16Type, Int32Type, Int64Type, Uint8Type, Uint16Type, Uint32Type, Uint64Type, UintptrType, Float32Type, Float64Type:
 		return []byte(f.String()), nil

field_test.go

@@ -45,12 +45,17 @@ func TestField(t *testing.T) {
 		{field: logger.Complex64("Complex64 field", 123), expectedValue: complex64(123), expectedType: logger.Complex64Type},
 		{field: logger.Complex128("Complex128 field", 123), expectedValue: complex128(123), expectedType: logger.Complex128Type},
 		{field: logger.String("String field", "my_value"), expectedValue: "my_value", expectedType: logger.StringType},
+		{field: logger.Binary("Binary field null", nil), expectedValue: []byte(nil), expectedType: logger.BinaryType},
 		{field: logger.Binary("Binary field", []byte("my_value")), expectedValue: []byte("my_value"), expectedType: logger.BinaryType},
+		{field: logger.ByteString("ByteString field null", nil), expectedValue: []byte(nil), expectedType: logger.ByteStringType},
 		{field: logger.ByteString("ByteString field", []byte("my_value")), expectedValue: []byte("my_value"), expectedType: logger.ByteStringType},
+		{field: logger.Error("Error nil field", nil), expectedValue: nil, expectedType: logger.ErrorType},
 		{field: logger.Error("Error field", err), expectedValue: err, expectedType: logger.ErrorType},
 		{field: logger.Time("Time field", now), expectedValue: now, expectedType: logger.TimeType},
 		{field: logger.Duration("Duration field", 5*time.Second), expectedValue: 5 * time.Second, expectedType: logger.DurationType},
+		{field: logger.Stringer("Stringer nil field", nil), expectedValue: nil, expectedType: logger.StringerType},
 		{field: logger.Stringer("Stringer field", MyStringer{}), expectedValue: MyStringer{}, expectedType: logger.StringerType},
+		{field: logger.Reflect("Reflect nil field", nil), expectedValue: nil, expectedType: logger.ReflectType},
 		{field: logger.Reflect("Reflect field", struct{}{}), expectedValue: struct{}{}, expectedType: logger.ReflectType},
 	}
 
@@ -127,12 +132,16 @@ func TestField_String(t *testing.T) {
 		{field: logger.Complex64("Complex64 field", 6+7i), expectedString: "(6+7i)"},
 		{field: logger.Complex128("Complex128 field", 6+7i), expectedString: "(6+7i)"},
 		{field: logger.String("String field", "my_value"), expectedString: "my_value"},
+		{field: logger.Binary("Binary nil field", nil), expectedString: ""},
 		{field: logger.Binary("Binary field", []byte{1, 2, 3}), expectedString: "\x01\x02\x03"},
+		{field: logger.ByteString("ByteString nil field", nil), expectedString: ""},
 		{field: logger.ByteString("ByteString field", []byte("my_value")), expectedString: "my_value"},
+		{field: logger.Error("Error nil field", nil), expectedString: "<nil>"},
 		{field: logger.Error("Error field", err), expectedString: "my_error_value"},
 		{field: logger.Time("Time field", now), expectedString: now.String()},
 		{field: logger.Duration("Duration field", 5*time.Second), expectedString: "5s"},
 		{field: logger.Stringer("Stringer field", MyStringer{}), expectedString: "my_stringer"},
+		{field: logger.Reflect("Reflect nil field", nil), expectedString: "<nil>"},
 		{field: logger.Reflect("Reflect field", struct{}{}), expectedString: "{}"},
 	}
 
@@ -170,12 +179,16 @@ func TestField_MarshalJSON(t *testing.T) {
 		{field: logger.Complex64("Complex64 field", 6+7i), expectedString: `"(6+7i)"`},
 		{field: logger.Complex128("Complex128 field", 6+7i), expectedString: `"(6+7i)"`},
 		{field: logger.String("String field", "my_value"), expectedString: `"my_value"`},
+		{field: logger.Binary("Binary nil field", nil), expectedString: `""`},
 		{field: logger.Binary("Binary field", []byte{1, 2, 3}), expectedString: `"\x01\x02\x03"`},
+		{field: logger.ByteString("ByteString nil field", nil), expectedString: `""`},
 		{field: logger.ByteString("ByteString field", []byte("my_value")), expectedString: `"my_value"`},
+		{field: logger.Error("Error nil field", nil), expectedString: "null"},
 		{field: logger.Error("Error field", err), expectedString: `"my_error_value"`},
 		{field: logger.Time("Time field", now), expectedString: string(nowMarshalled)},
 		{field: logger.Duration("Duration field", 5*time.Second), expectedString: `"5s"`},
 		{field: logger.Stringer("Stringer field", MyStringer{}), expectedString: `"my_stringer"`},
+		{field: logger.Reflect("Reflect nil field", nil), expectedString: "null"},
 		{field: logger.Reflect("Reflect field", struct{}{}), expectedString: "{}"},
 	}