feat: add nullable bool defaulting to false (#758)

sqlxx/types.go

@@ -163,6 +163,56 @@ func (ns *NullBool) UnmarshalJSON(data []byte) error {
 	return errors.WithStack(json.Unmarshal(data, &ns.Bool))
 }
 
+// FalsyNullBool represents a bool that may be null.
+// It JSON decodes to false if null.
+//
+// swagger:type bool
+// swagger:model falsyNullBool
+type FalsyNullBool struct {
+	Bool  bool
+	Valid bool // Valid is true if Bool is not NULL
+}
+
+// Scan implements the Scanner interface.
+func (ns *FalsyNullBool) Scan(value interface{}) error {
+	var d = sql.NullBool{}
+	if err := d.Scan(value); err != nil {
+		return err
+	}
+
+	ns.Bool = d.Bool
+	ns.Valid = d.Valid
+	return nil
+}
+
+// Value implements the driver Valuer interface.
+func (ns FalsyNullBool) Value() (driver.Value, error) {
+	if !ns.Valid {
+		return nil, nil
+	}
+	return ns.Bool, nil
+}
+
+// MarshalJSON returns m as the JSON encoding of m.
+func (ns FalsyNullBool) MarshalJSON() ([]byte, error) {
+	if !ns.Valid {
+		return []byte("false"), nil
+	}
+	return json.Marshal(ns.Bool)
+}
+
+// UnmarshalJSON sets *m to a copy of data.
+func (ns *FalsyNullBool) UnmarshalJSON(data []byte) error {
+	if ns == nil {
+		return errors.New("json.RawMessage: UnmarshalJSON on nil pointer")
+	}
+	if len(data) == 0 || string(data) == "null" {
+		return nil
+	}
+	ns.Valid = true
+	return errors.WithStack(json.Unmarshal(data, &ns.Bool))
+}
+
 // swagger:type string
 // swagger:model nullString
 type NullString string

sqlxx/types_test.go

@@ -64,6 +64,42 @@ func TestNullBoolMarshalJSON(t *testing.T) {
 	}
 }
 
+func TestNullBoolDefaultFalseMarshalJSON(t *testing.T) {
+	type outer struct {
+		Bool *FalsyNullBool `json:"null_bool,omitempty"`
+	}
+
+	for k, tc := range []struct {
+		in       *outer
+		expected string
+	}{
+		{in: &outer{&FalsyNullBool{Valid: false, Bool: true}}, expected: "{\"null_bool\":false}"},
+		{in: &outer{&FalsyNullBool{Valid: false, Bool: false}}, expected: "{\"null_bool\":false}"},
+		{in: &outer{&FalsyNullBool{Valid: true, Bool: true}}, expected: "{\"null_bool\":true}"},
+		{in: &outer{&FalsyNullBool{Valid: true, Bool: false}}, expected: "{\"null_bool\":false}"},
+		{in: &outer{}, expected: "{}"},
+	} {
+		t.Run(fmt.Sprintf("case=%d", k), func(t *testing.T) {
+			out, err := json.Marshal(tc.in)
+			require.NoError(t, err)
+			assert.EqualValues(t, tc.expected, string(out))
+
+			var actual outer
+			require.NoError(t, json.Unmarshal(out, &actual))
+			if tc.in.Bool == nil {
+				assert.Nil(t, actual.Bool)
+				return
+			} else if !tc.in.Bool.Valid {
+				assert.False(t, actual.Bool.Bool)
+				return
+			}
+
+			assert.EqualValues(t, tc.in.Bool.Bool, actual.Bool.Bool)
+			assert.EqualValues(t, tc.in.Bool.Valid, actual.Bool.Valid)
+		})
+	}
+}
+
 func TestNullInt64MarshalJSON(t *testing.T) {
 	type outer struct {
 		Int64 *NullInt64 `json:"null_int,omitempty"`