feat!: add union types support in go (#1882)

docs/migrations/version-3-to-4.md

@@ -214,3 +214,28 @@ class Address:
 ### File names
 
 In v4, file names for go will be formatted as `snake_case.go`. This is the "standard" in go: https://github.com/golang/go/issues/36060
+
+
+### Union types will be generated correctly with struct embeddings
+
+Modelina now supports union types for `Go`. Since `Go` does not have native union types support modelina uses `struct embeddings` to mock union types.
+
+```go
+type Union struct {
+  CustomStruct
+  int
+  string
+  ModelinaArrType []string
+  ModelinaDictType map[string] interface{}
+  ModelinaAnyType interface {}
+}
+```
+`ModelinaArrType`, `ModelinaDictType`, `ModelinaAnyType` are generated by default by modelina, users can change the names by passing different names to the `GoGenerator Options`, for example:
+
+```ts
+const generator = new GoGenerator({
+  unionAnyModelName: 'ModelinaAnyType',
+  unionArrModelName: 'ModelinaArrType',
+  unionDictModelName: 'ModelinaDictType'
+});
+```

examples/go-union-type/README.md

@@ -0,0 +1,26 @@
+# Go Union Types
+
+Modelina now supports union types for `Go`. Since `Go` does not have native union types support modelina uses `struct embeddings` to mock union types. Modelina has custom names for models that are not directly embedded in structs. Users can update the default names by passing custom values. 
+
+
+```ts
+const generator = new GoGenerator({
+  unionAnyModelName: 'ModelinaAnyType',
+  unionArrModelName: 'ModelinaArrType',
+  unionDictModelName: 'ModelinaDictType'
+});
+```
+
+## How to run this example
+
+Run this example using:
+
+```sh
+npm i && npm run start
+```
+
+If you are on Windows, use the `start:windows` script instead:
+
+```sh
+npm i && npm run start:windows
+```

examples/go-union-type/__snapshots__/index.spec.ts.snap

@@ -0,0 +1,64 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`Should be able to render union types and should log expected output to console 1`] = `
+Array [
+  "// AdditionalProperty represents a AdditionalProperty model.
+type AdditionalProperty struct {
+  AdditionalPropertyOneOf_0
+  AdditionalPropertyOneOf_1
+  string
+  float64
+  ModelinaArrType []string
+  ModelinaArrType []Union
+  AdditionalPropertyOneOf_6
+}",
+]
+`;
+
+exports[`Should be able to render union types and should log expected output to console 2`] = `
+Array [
+  "// Union represents a Union model.
+type Union struct {
+  string
+  float64
+  ModelinaAnyType interface{}
+}",
+]
+`;
+
+exports[`Should be able to render union types and should log expected output to console 3`] = `
+Array [
+  "// AdditionalPropertyOneOf_6 represents a AdditionalPropertyOneOf_6 model.
+type AdditionalPropertyOneOf_6 struct {
+  string
+  float64
+  bool
+}",
+]
+`;
+
+exports[`Should be able to render union types and should log expected output to console 4`] = `
+Array [
+  "",
+]
+`;
+
+exports[`Should be able to render union types and should log expected output to console 5`] = `
+Array [
+  "// AdditionalPropertyOneOf_0 represents a AdditionalPropertyOneOf_0 model.
+type AdditionalPropertyOneOf_0 struct {
+  Ref string
+  AdditionalProperties map[string]interface{}
+}",
+]
+`;
+
+exports[`Should be able to render union types and should log expected output to console 6`] = `
+Array [
+  "// AdditionalPropertyOneOf_1 represents a AdditionalPropertyOneOf_1 model.
+type AdditionalPropertyOneOf_1 struct {
+  Id string
+  AdditionalProperties map[string]interface{}
+}",
+]
+`;

examples/go-union-type/index.spec.ts

@@ -0,0 +1,20 @@
+const spy = jest.spyOn(global.console, 'log').mockImplementation(() => {
+  return;
+});
+import { generate } from './index';
+
+describe('Should be able to render union types', () => {
+  afterAll(() => {
+    jest.restoreAllMocks();
+  });
+  test('and should log expected output to console', async () => {
+    await generate();
+    expect(spy.mock.calls.length).toEqual(6);
+    expect(spy.mock.calls[0]).toMatchSnapshot();
+    expect(spy.mock.calls[1]).toMatchSnapshot();
+    expect(spy.mock.calls[2]).toMatchSnapshot();
+    expect(spy.mock.calls[3]).toMatchSnapshot();
+    expect(spy.mock.calls[4]).toMatchSnapshot();
+    expect(spy.mock.calls[5]).toMatchSnapshot();
+  });
+});

examples/go-union-type/index.ts

@@ -0,0 +1,33 @@
+import { GoGenerator } from '../../src';
+
+const generator = new GoGenerator({
+  unionAnyModelName: 'ModelinaAnyType',
+  unionArrModelName: 'ModelinaArrType',
+  unionDictModelName: 'ModelinaDictType'
+});
+
+const jsonSchemaDraft7 = {
+  $schema: 'http://json-schema.org/draft-07/schema#',
+  type: 'object',
+  additionalProperties: {
+    oneOf: [
+      { type: 'object', properties: { ref: { type: 'string' } } },
+      { type: 'object', properties: { Id: { type: 'string' } } },
+      { type: 'string' },
+      { type: 'number' },
+      { type: 'array', items: { type: 'string' } },
+      { type: 'array', items: [{ type: 'string' }, { type: 'number' }] },
+      { oneOf: [{ type: 'string' }, { type: 'number' }, { type: 'boolean' }] }
+    ]
+  }
+};
+
+export async function generate(): Promise<void> {
+  const models = await generator.generate(jsonSchemaDraft7);
+  for (const model of models) {
+    console.log(model.result);
+  }
+}
+if (require.main === module) {
+  generate();
+}

examples/go-union-type/package.json

@@ -0,0 +1,10 @@
+{
+  "config" : { "example_name" : "go-union-type" },
+  "scripts": {
+    "install": "cd ../.. && npm i",
+    "start": "../../node_modules/.bin/ts-node --cwd ../../ ./examples/$npm_package_config_example_name/index.ts",
+    "start:windows": "..\\..\\node_modules\\.bin\\ts-node --cwd ..\\..\\ .\\examples\\%npm_package_config_example_name%\\index.ts",
+    "test": "../../node_modules/.bin/jest --config=../../jest.config.js ./examples/$npm_package_config_example_name/index.spec.ts",
+    "test:windows": "..\\..\\node_modules\\.bin\\jest --config=..\\..\\jest.config.js examples/%npm_package_config_example_name%/index.spec.ts"
+  }
+}

src/generators/go/GoConstrainer.ts

@@ -39,9 +39,9 @@ export const GoDefaultTypeMapping: GoTypeMapping = {
   Enum({ constrainedModel }): string {
     return constrainedModel.name;
   },
-  Union(): string {
+  Union({ constrainedModel }): string {
     //Because Go have no notion of unions (and no custom implementation), we have to render it as any value.
-    return 'interface{}';
+    return constrainedModel.name;
   },
   Dictionary({ constrainedModel }): string {
     return `map[${constrainedModel.key.type}]${constrainedModel.value.type}`;

src/generators/go/GoGenerator.ts

@@ -11,6 +11,7 @@ import {
   ConstrainedObjectModel,
   ConstrainedEnumModel,
   ConstrainedMetaModel,
+  ConstrainedUnionModel,
   MetaModel
 } from '../../models';
 import {
@@ -32,10 +33,20 @@ import { Logger } from '../../utils/LoggingInterface';
 import { GoDefaultConstraints, GoDefaultTypeMapping } from './GoConstrainer';
 import { DeepPartial, mergePartialAndDefault } from '../../utils/Partials';
 import { GoDependencyManager } from './GoDependencyManager';
+import { UnionRenderer } from './renderers/UnionRenderer';
 
+/**
+ * @typedef GoOptions
+ * @prop {string} unionAnyModelName  Change default name for any models.
+ * @prop {string} unionDictModelName Change default name for Dictionary Models.
+ * @prop {string} unionArrModelName  Change default name for Array models.
+ */
 export interface GoOptions extends CommonGeneratorOptions<GoPreset> {
   typeMapping: TypeMapping<GoOptions, GoDependencyManager>;
   constraints: Constraints<GoOptions>;
+  unionAnyModelName: string;
+  unionDictModelName: string;
+  unionArrModelName: string;
 }
 export type GoConstantConstraint = ConstantConstraint<GoOptions>;
 export type GoEnumKeyConstraint = EnumKeyConstraint<GoOptions>;
@@ -48,9 +59,6 @@ export interface GoRenderCompleteModelOptions {
   packageName: string;
 }
 
-/**
- * Generator for Go
- */
 export class GoGenerator extends AbstractGenerator<
   GoOptions,
   GoRenderCompleteModelOptions
@@ -59,7 +67,10 @@ export class GoGenerator extends AbstractGenerator<
     ...defaultGeneratorOptions,
     defaultPreset: GO_DEFAULT_PRESET,
     typeMapping: GoDefaultTypeMapping,
-    constraints: GoDefaultConstraints
+    constraints: GoDefaultConstraints,
+    unionAnyModelName: 'ModelinaAnyType',
+    unionDictModelName: 'ModelinaDictType',
+    unionArrModelName: 'ModelinaArrType'
   };
 
   static defaultCompleteModelOptions: GoRenderCompleteModelOptions = {
@@ -99,7 +110,8 @@ export class GoGenerator extends AbstractGenerator<
     //These are the models that we have separate renderers for
     const metaModelsToSplit: SplitOptions = {
       splitEnum: true,
-      splitObject: true
+      splitObject: true,
+      splitUnion: true
     };
     return split(model, metaModelsToSplit);
   }
@@ -142,6 +154,12 @@ export class GoGenerator extends AbstractGenerator<
         args.inputModel,
         optionsToUse
       );
+    } else if (args.constrainedModel instanceof ConstrainedUnionModel) {
+      return this.renderUnion(
+        args.constrainedModel,
+        args.inputModel,
+        optionsToUse
+      );
     }
     Logger.warn(
       `Go generator, cannot generate this type of model, ${args.constrainedModel.name}`
@@ -255,4 +273,30 @@ ${outputModel.result}`;
       dependencies: dependencyManagerToUse.dependencies
     });
   }
+  async renderUnion(
+    model: ConstrainedUnionModel,
+    inputModel: InputMetaModel,
+    options?: DeepPartial<GoOptions>
+  ): Promise<RenderOutput> {
+    const optionsToUse = GoGenerator.getGoOptions({
+      ...this.options,
+      ...options
+    });
+    const dependencyManagerToUse = this.getDependencyManager(optionsToUse);
+    const presets = this.getPresets('union');
+    const renderer = new UnionRenderer(
+      optionsToUse,
+      this,
+      presets,
+      model,
+      inputModel,
+      dependencyManagerToUse
+    );
+    const result = await renderer.runSelfPreset();
+    return RenderOutput.toRenderOutput({
+      result,
+      renderedName: model.name,
+      dependencies: dependencyManagerToUse.dependencies
+    });
+  }
 }

src/generators/go/GoPreset.ts

@@ -6,25 +6,42 @@ import {
   ConstrainedObjectModel,
   ConstrainedObjectPropertyModel,
   ConstrainedEnumModel,
-  EnumArgs
+  EnumArgs,
+  ConstrainedUnionModel,
+  ConstrainedMetaModel
 } from '../../models';
 import {
   StructRenderer,
   GO_DEFAULT_STRUCT_PRESET
 } from './renderers/StructRenderer';
 import { EnumRenderer, GO_DEFAULT_ENUM_PRESET } from './renderers/EnumRenderer';
+import {
+  GO_DEFAULT_UNION_PRESET,
+  UnionRenderer
+} from './renderers/UnionRenderer';
 import { GoOptions } from './GoGenerator';
 
 export interface FieldArgs {
   field: ConstrainedObjectPropertyModel;
 }
 
+export interface UnionFieldArgs {
+  field: ConstrainedMetaModel;
+}
+
 export interface StructPreset<R extends AbstractRenderer, O>
   extends CommonPreset<R, O, ConstrainedObjectModel> {
   field?: (
     args: PresetArgs<R, O, ConstrainedObjectModel> & FieldArgs
   ) => Promise<string> | string;
 }
+
+export interface UnionPreset<R extends AbstractRenderer, O>
+  extends CommonPreset<R, O, ConstrainedUnionModel> {
+  field?: (
+    args: PresetArgs<R, O, ConstrainedUnionModel> & UnionFieldArgs
+  ) => Promise<string> | string;
+}
 interface EnumPreset<R extends AbstractRenderer, O>
   extends CommonPreset<R, O, ConstrainedEnumModel> {
   item?: (
@@ -33,13 +50,16 @@ interface EnumPreset<R extends AbstractRenderer, O>
 }
 export type StructPresetType<O> = StructPreset<StructRenderer, O>;
 export type EnumPresetType<O> = EnumPreset<EnumRenderer, O>;
+export type UnionPresetType<O> = UnionPreset<UnionRenderer, O>;
 
 export type GoPreset<O = any> = Preset<{
   struct: StructPresetType<O>;
   enum: EnumPresetType<O>;
+  union: UnionPresetType<O>;
 }>;
 
 export const GO_DEFAULT_PRESET: GoPreset<GoOptions> = {
   struct: GO_DEFAULT_STRUCT_PRESET,
-  enum: GO_DEFAULT_ENUM_PRESET
+  enum: GO_DEFAULT_ENUM_PRESET,
+  union: GO_DEFAULT_UNION_PRESET
 };