Feat: support nullable option (#5736)

Signed-off-by: iyear <ljyngup@gmail.com>

references/cuegen/convert.go

@@ -93,11 +93,16 @@ func (g *Generator) convert(typ gotypes.Type) (cueast.Expr, error) {
 		if err != nil {
 			return nil, err
 		}
-		return &cueast.BinaryExpr{
-			X:  cueast.NewNull(),
-			Op: cuetoken.OR,
-			Y:  expr,
-		}, nil
+
+		// generate null enum for pointer type
+		if g.opts.nullable {
+			return &cueast.BinaryExpr{
+				X:  cueast.NewNull(),
+				Op: cuetoken.OR,
+				Y:  expr,
+			}, nil
+		}
+		return expr, nil
 	case *gotypes.Slice:
 		if t.Elem().String() == "byte" {
 			return ident("bytes", false), nil

references/cuegen/convert_test.go

@@ -63,3 +63,16 @@ func TestConvertInvalid(t *testing.T) {
 		t.Error(err)
 	}
 }
+
+func TestConvertNullable(t *testing.T) {
+	g, err := NewGenerator("testdata/nullable.go")
+	assert.NoError(t, err)
+
+	got := &bytes.Buffer{}
+	assert.NoError(t, g.Generate(got, WithNullable()))
+
+	want, err := os.ReadFile("testdata/nullable.cue")
+	assert.NoError(t, err)
+
+	assert.Equal(t, got.String(), string(want))
+}

references/cuegen/option.go

@@ -18,6 +18,7 @@ package cuegen
 
 type options struct {
 	anyTypes map[string]struct{}
+	nullable bool
 }
 
 var defaultOptions = &options{
@@ -25,6 +26,7 @@ var defaultOptions = &options{
 		"map[string]interface{}": {}, "map[string]any": {},
 		"interface{}": {}, "any": {},
 	},
+	nullable: false,
 }
 
 // Option is a function that configures generation options
@@ -42,3 +44,10 @@ func WithAnyTypes(types ...string) Option {
 		}
 	}
 }
+
+// WithNullable will generate null enum for pointer type
+func WithNullable() Option {
+	return func(opts *options) {
+		opts.nullable = true
+	}
+}

references/cuegen/option_test.go

@@ -47,10 +47,29 @@ func TestWithAnyTypes(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		opts := options{map[string]struct{}{}}
+		opts := options{anyTypes: map[string]struct{}{}}
 		for _, opt := range tt.opts {
 			opt(&opts)
 		}
 		assert.Equal(t, opts.anyTypes, tt.extra, tt.name)
 	}
 }
+
+func TestWithNullable(t *testing.T) {
+	tests := []struct {
+		name string
+		opts []Option
+		want bool
+	}{
+		{name: "default", opts: nil, want: false},
+		{name: "true", opts: []Option{WithNullable()}, want: true},
+	}
+
+	for _, tt := range tests {
+		opts := options{nullable: false}
+		for _, opt := range tt.opts {
+			opt(&opts)
+		}
+		assert.Equal(t, opts.nullable, tt.want, tt.name)
+	}
+}

references/cuegen/testdata/nullable.cue

@@ -0,0 +1,14 @@
+package testdata
+
+Nullable: {
+	field1?: null | string
+	field2?: null | int
+	field3?: null | bool
+	Field4:  null | {
+		field1: null | string
+		field2: null | int
+		field3: null | bool
+	}
+	field5?: null | [...string]
+	field6?: null | [...int]
+}

references/cuegen/testdata/nullable.go

@@ -0,0 +1,30 @@
+/*
+Copyright 2023 The KubeVela Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package testdata
+
+type Nullable struct {
+	Field1 *string `json:"field1,omitempty"`
+	Field2 *int    `json:"field2,omitempty"`
+	Field3 *bool   `json:"field3,omitempty"`
+	Field4 *struct {
+		Field1 *string `json:"field1"`
+		Field2 *int    `json:"field2"`
+		Field3 *bool   `json:"field3"`
+	}
+	Field5 *[]string `json:"field5,omitempty"`
+	Field6 *[]int    `json:"field6,omitempty"`
+}

references/cuegen/testdata/valid.cue

@@ -52,7 +52,7 @@ AnonymousField: SmallStruct: {
 	field1: string
 	field2: string
 }
-ReferenceField: field1: null | {
+ReferenceField: field1: {
 	field1: string
 	field2: string
 }
@@ -61,7 +61,7 @@ StructField: {
 		field1: string
 		field2: string
 	}
-	field2: null | {
+	field2: {
 		field1: string
 		field2: string
 	}