Make optional.Option[T] type serializable (#29282)

make the generic `Option` type de-/serializable for json and yaml

---------

Co-authored-by: KN4CK3R <admin@oldschoolhack.me>

3 files changed, 248 insertions, 10 deletions

diff --git a/modules/optional/option_test.go b/modules/optional/option_test.go
index bfc4577dbe..410fd73577 100644
--- a/modules/optional/option_test.go
+++ b/modules/optional/option_test.go
@@ -1,47 +1,49 @@
 // Copyright 2024 The Gitea Authors. All rights reserved.
 // SPDX-License-Identifier: MIT
 
-package optional
+package optional_test
 
 import (
 	"testing"
 
+	"code.gitea.io/gitea/modules/optional"
+
 	"github.com/stretchr/testify/assert"
 )
 
 func TestOption(t *testing.T) {
-	var uninitialized Option[int]
+	var uninitialized optional.Option[int]
 	assert.False(t, uninitialized.Has())
 	assert.Equal(t, int(0), uninitialized.Value())
 	assert.Equal(t, int(1), uninitialized.ValueOrDefault(1))
 
-	none := None[int]()
+	none := optional.None[int]()
 	assert.False(t, none.Has())
 	assert.Equal(t, int(0), none.Value())
 	assert.Equal(t, int(1), none.ValueOrDefault(1))
 
-	some := Some[int](1)
+	some := optional.Some[int](1)
 	assert.True(t, some.Has())
 	assert.Equal(t, int(1), some.Value())
 	assert.Equal(t, int(1), some.ValueOrDefault(2))
 
 	var ptr *int
-	assert.False(t, FromPtr(ptr).Has())
+	assert.False(t, optional.FromPtr(ptr).Has())
 
 	int1 := 1
-	opt1 := FromPtr(&int1)
+	opt1 := optional.FromPtr(&int1)
 	assert.True(t, opt1.Has())
 	assert.Equal(t, int(1), opt1.Value())
 
-	assert.False(t, FromNonDefault("").Has())
+	assert.False(t, optional.FromNonDefault("").Has())
 
-	opt2 := FromNonDefault("test")
+	opt2 := optional.FromNonDefault("test")
 	assert.True(t, opt2.Has())
 	assert.Equal(t, "test", opt2.Value())
 
-	assert.False(t, FromNonDefault(0).Has())
+	assert.False(t, optional.FromNonDefault(0).Has())
 
-	opt3 := FromNonDefault(1)
+	opt3 := optional.FromNonDefault(1)
 	assert.True(t, opt3.Has())
 	assert.Equal(t, int(1), opt3.Value())
 }
diff --git a/modules/optional/serialization.go b/modules/optional/serialization.go
new file mode 100644
index 0000000000..6688e78cd1
--- /dev/null
+++ b/modules/optional/serialization.go
@@ -0,0 +1,46 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package optional
+
+import (
+	"code.gitea.io/gitea/modules/json"
+
+	"gopkg.in/yaml.v3"
+)
+
+func (o *Option[T]) UnmarshalJSON(data []byte) error {
+	var v *T
+	if err := json.Unmarshal(data, &v); err != nil {
+		return err
+	}
+	*o = FromPtr(v)
+	return nil
+}
+
+func (o Option[T]) MarshalJSON() ([]byte, error) {
+	if !o.Has() {
+		return []byte("null"), nil
+	}
+
+	return json.Marshal(o.Value())
+}
+
+func (o *Option[T]) UnmarshalYAML(value *yaml.Node) error {
+	var v *T
+	if err := value.Decode(&v); err != nil {
+		return err
+	}
+	*o = FromPtr(v)
+	return nil
+}
+
+func (o Option[T]) MarshalYAML() (interface{}, error) {
+	if !o.Has() {
+		return nil, nil
+	}
+
+	value := new(yaml.Node)
+	err := value.Encode(o.Value())
+	return value, err
+}
diff --git a/modules/optional/serialization_test.go b/modules/optional/serialization_test.go
new file mode 100644
index 0000000000..09a4bddea0
--- /dev/null
+++ b/modules/optional/serialization_test.go
@@ -0,0 +1,190 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package optional_test
+
+import (
+	std_json "encoding/json" //nolint:depguard
+	"testing"
+
+	"code.gitea.io/gitea/modules/json"
+	"code.gitea.io/gitea/modules/optional"
+
+	"github.com/stretchr/testify/assert"
+	"gopkg.in/yaml.v3"
+)
+
+type testSerializationStruct struct {
+	NormalString string                  `json:"normal_string" yaml:"normal_string"`
+	NormalBool   bool                    `json:"normal_bool" yaml:"normal_bool"`
+	OptBool      optional.Option[bool]   `json:"optional_bool,omitempty" yaml:"optional_bool,omitempty"`
+	OptString    optional.Option[string] `json:"optional_string,omitempty" yaml:"optional_string,omitempty"`
+	OptTwoBool   optional.Option[bool]   `json:"optional_two_bool" yaml:"optional_two_bool"`
+	OptTwoString optional.Option[string] `json:"optional_twostring" yaml:"optional_two_string"`
+}
+
+func TestOptionalToJson(t *testing.T) {
+	tests := []struct {
+		name string
+		obj  *testSerializationStruct
+		want string
+	}{
+		{
+			name: "empty",
+			obj:  new(testSerializationStruct),
+			want: `{"normal_string":"","normal_bool":false,"optional_two_bool":null,"optional_twostring":null}`,
+		},
+		{
+			name: "some",
+			obj: &testSerializationStruct{
+				NormalString: "a string",
+				NormalBool:   true,
+				OptBool:      optional.Some(false),
+				OptString:    optional.Some(""),
+				OptTwoBool:   optional.None[bool](),
+				OptTwoString: optional.None[string](),
+			},
+			want: `{"normal_string":"a string","normal_bool":true,"optional_bool":false,"optional_string":"","optional_two_bool":null,"optional_twostring":null}`,
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			b, err := json.Marshal(tc.obj)
+			assert.NoError(t, err)
+			assert.EqualValues(t, tc.want, string(b), "gitea json module returned unexpected")
+
+			b, err = std_json.Marshal(tc.obj)
+			assert.NoError(t, err)
+			assert.EqualValues(t, tc.want, string(b), "std json module returned unexpected")
+		})
+	}
+}
+
+func TestOptionalFromJson(t *testing.T) {
+	tests := []struct {
+		name string
+		data string
+		want testSerializationStruct
+	}{
+		{
+			name: "empty",
+			data: `{}`,
+			want: testSerializationStruct{
+				NormalString: "",
+			},
+		},
+		{
+			name: "some",
+			data: `{"normal_string":"a string","normal_bool":true,"optional_bool":false,"optional_string":"","optional_two_bool":null,"optional_twostring":null}`,
+			want: testSerializationStruct{
+				NormalString: "a string",
+				NormalBool:   true,
+				OptBool:      optional.Some(false),
+				OptString:    optional.Some(""),
+			},
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			var obj1 testSerializationStruct
+			err := json.Unmarshal([]byte(tc.data), &obj1)
+			assert.NoError(t, err)
+			assert.EqualValues(t, tc.want, obj1, "gitea json module returned unexpected")
+
+			var obj2 testSerializationStruct
+			err = std_json.Unmarshal([]byte(tc.data), &obj2)
+			assert.NoError(t, err)
+			assert.EqualValues(t, tc.want, obj2, "std json module returned unexpected")
+		})
+	}
+}
+
+func TestOptionalToYaml(t *testing.T) {
+	tests := []struct {
+		name string
+		obj  *testSerializationStruct
+		want string
+	}{
+		{
+			name: "empty",
+			obj:  new(testSerializationStruct),
+			want: `normal_string: ""
+normal_bool: false
+optional_two_bool: null
+optional_two_string: null
+`,
+		},
+		{
+			name: "some",
+			obj: &testSerializationStruct{
+				NormalString: "a string",
+				NormalBool:   true,
+				OptBool:      optional.Some(false),
+				OptString:    optional.Some(""),
+			},
+			want: `normal_string: a string
+normal_bool: true
+optional_bool: false
+optional_string: ""
+optional_two_bool: null
+optional_two_string: null
+`,
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			b, err := yaml.Marshal(tc.obj)
+			assert.NoError(t, err)
+			assert.EqualValues(t, tc.want, string(b), "yaml module returned unexpected")
+		})
+	}
+}
+
+func TestOptionalFromYaml(t *testing.T) {
+	tests := []struct {
+		name string
+		data string
+		want testSerializationStruct
+	}{
+		{
+			name: "empty",
+			data: ``,
+			want: testSerializationStruct{},
+		},
+		{
+			name: "empty but init",
+			data: `normal_string: ""
+normal_bool: false
+optional_bool:
+optional_two_bool:
+optional_two_string:
+`,
+			want: testSerializationStruct{},
+		},
+		{
+			name: "some",
+			data: `
+normal_string: a string
+normal_bool: true
+optional_bool: false
+optional_string: ""
+optional_two_bool: null
+optional_twostring: null
+`,
+			want: testSerializationStruct{
+				NormalString: "a string",
+				NormalBool:   true,
+				OptBool:      optional.Some(false),
+				OptString:    optional.Some(""),
+			},
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			var obj testSerializationStruct
+			err := yaml.Unmarshal([]byte(tc.data), &obj)
+			assert.NoError(t, err)
+			assert.EqualValues(t, tc.want, obj, "yaml module returned unexpected")
+		})
+	}
+}