fix: enable controller update in case of multiple belongsTo relation

packages/cli/generators/relation/belongs-to-relation.generator.js

@@ -65,13 +65,57 @@ module.exports = class BelongsToRelationGenerator extends (
       path.join(this.artifactInfo.outDir, this.artifactInfo.outFile),
     );
 
-    this.copyTemplatedFiles(source, dest, this.artifactInfo);
-    await relationUtils.addExportController(
-      this,
-      path.resolve(this.artifactInfo.outDir, 'index.ts'),
-      this.artifactInfo.controllerClassName,
-      utils.toFileName(this.artifactInfo.name) + '.controller',
-    );
+    if (this.fs.exists(dest)) {
+      const project = new relationUtils.AstLoopBackProject();
+      const sourceFile = project.addSourceFileAtPath(dest);
+      const sourceClass = relationUtils.getClassObj(
+        sourceFile,
+        this.artifactInfo.controllerClassName,
+      );
+      const structure = sourceClass.getStructure();
+      structure.methods.forEach((method, index) => {
+        if (method.name.startsWith('get')) {
+          const {statements, parameters} = method;
+          const lastStatementIndex = statements.length - 1;
+          let returnStatement = statements[lastStatementIndex];
+          returnStatement = returnStatement.substring(
+            returnStatement.indexOf('return') + 6,
+            returnStatement.lastIndexOf(';'),
+          );
+          returnStatement = returnStatement.trim();
+
+          if (returnStatement.startsWith('[')) {
+            returnStatement = returnStatement.substring(
+              returnStatement.indexOf('[') + 1,
+              returnStatement.lastIndexOf(']'),
+            );
+          }
+          returnStatement = `${returnStatement},\n\t this.${this.artifactInfo.paramSourceRepository}.${this.artifactInfo.relationPropertyName}(${this.artifactInfo.sourceModelPrimaryKey})`;
+          structure.methods[index].statements[lastStatementIndex] =
+            `return [${returnStatement}];`;
+          structure.methods[index].returnType =
+            `Promise<Promise<${this.artifactInfo.targetModelClassName}>[]>`;
+          parameters.forEach(({decorators}, paramIndex) => {
+            decorators.forEach((decorator, decorIndex) => {
+              structure.methods[index].parameters[paramIndex].decorators[
+                decorIndex
+              ].name = `param.path.${decorator.name}`;
+            });
+          });
+        }
+      });
+      sourceClass.set(structure);
+      sourceClass.formatText();
+      await sourceFile.save();
+    } else {
+      this.copyTemplatedFiles(source, dest, this.artifactInfo);
+      await relationUtils.addExportController(
+        this,
+        path.resolve(this.artifactInfo.outDir, 'index.ts'),
+        this.artifactInfo.controllerClassName,
+        utils.toFileName(this.artifactInfo.name) + '.controller',
+      );
+    }
   }
 
   async generateModels(options) {

packages/cli/snapshots/integration/generators/relation.belongs-to.integration.snapshots.js

@@ -238,6 +238,92 @@ export * from './order-customer.controller';
 `;
 
 
+exports[`lb4 relation checks if the controller file created for multiple relations answers {"relationType":"belongsTo","sourceModel":"Task","destinationModel":"Employee","relationName":"assignedTo"} checks controller content with belongsTo relation for multiple relations 1`] = `
+import {
+  repository,
+} from '@loopback/repository';
+import {
+  param,
+  get,
+  getModelSchemaRef,
+} from '@loopback/rest';
+import {
+  Task,
+  Employee,
+} from '../models';
+import {TaskRepository} from '../repositories';
+
+export class TaskEmployeeController {
+  constructor(
+    @repository(TaskRepository)
+    public taskRepository: TaskRepository,
+  ) { }
+
+  @get('/tasks/{id}/employee', {
+    responses: {
+      '200': {
+        description: 'Employee belonging to Task',
+        content: {
+          'application/json': {
+            schema: getModelSchemaRef(Employee),
+          },
+        },
+      },
+    },
+  })
+  async getEmployee(
+    @param.path.number('id') id: typeof Task.prototype.id,
+  ): Promise<Employee> {
+    return this.taskRepository.assignedTo(id);
+  }
+}
+
+`;
+
+
+exports[`lb4 relation checks if the controller file created for multiple relations answers {"relationType":"belongsTo","sourceModel":"Task","destinationModel":"Employee","relationName":"createdBy"} checks controller content with belongsTo relation for multiple relations 1`] = `
+import {
+  repository,
+} from '@loopback/repository';
+import {
+  param,
+  get,
+  getModelSchemaRef,
+} from '@loopback/rest';
+import {
+  Task,
+  Employee,
+} from '../models';
+import {TaskRepository} from '../repositories';
+
+export class TaskEmployeeController {
+  constructor(
+    @repository(TaskRepository)
+    public taskRepository: TaskRepository,
+  ) { }
+
+  @get('/tasks/{id}/employee', {
+    responses: {
+      '200': {
+        description: 'Employee belonging to Task',
+        content: {
+          'application/json': {
+            schema: getModelSchemaRef(Employee),
+          },
+        },
+      },
+    },
+  })
+  async getEmployee(
+    @param.path.number('id') id: typeof Task.prototype.id,
+  ): Promise<Employee> {
+    return this.taskRepository.createdBy(id);
+  }
+}
+
+`;
+
+
 exports[`lb4 relation checks if the controller file created for same table relation answers {"relationType":"belongsTo","sourceModel":"Employee","destinationModel":"Employee"} checks controller content with belongsTo relation with same table 1`] = `
 export class EmployeeController {}
 

packages/cli/test/fixtures/relation/controllers/task-employee.controller.ts

@@ -0,0 +1 @@
+export class TaskEmployeeController {}

packages/cli/test/fixtures/relation/index.js

@@ -234,6 +234,7 @@ exports.SANDBOX_FILES = [
   SourceEntries.PatientRepository,
   SourceEntries.AppointmentRepository,
   SourceEntries.EmployeeRepository,
+  SourceEntries.TaskRepository,
 
   SourceEntries.AccountModel,
   SourceEntries.CustomerModel,

packages/cli/test/fixtures/relation/models/task.model.ts

@@ -0,0 +1,20 @@
+import {Entity, model, property} from '@loopback/repository';
+
+@model()
+export class Task extends Entity {
+  @property({
+    type: 'number',
+    id: true,
+    default: 0,
+  })
+  id?: number;
+
+  @property({
+    type: 'string',
+  })
+  title?: string;
+
+  constructor(data?: Partial<Task>) {
+    super(data);
+  }
+}

packages/cli/test/fixtures/relation/repositories/task.repository.ts

@@ -0,0 +1,17 @@
+import {inject} from '@loopback/core';
+import {BelongsToAccessor, DefaultCrudRepository} from '@loopback/repository';
+import {DbDataSource} from '../datasources';
+import {Customer, Task} from '../models';
+
+export class TaskRepository extends DefaultCrudRepository<
+  Task,
+  typeof Task.prototype.id
+> {
+  public readonly myCustomer: BelongsToAccessor<
+    Customer,
+    typeof Task.prototype.id
+  >;
+  constructor(@inject('datasources.db') dataSource: DbDataSource) {
+    super(Task, dataSource);
+  }
+}

packages/cli/test/integration/generators/relation.belongs-to.integration.js

@@ -23,6 +23,7 @@ const sandbox = new TestSandbox(path.resolve(__dirname, '../.sandbox'));
 const sourceFileName = 'order.model.ts';
 const controllerFileName = 'order-customer.controller.ts';
 const controllerFileNameForSameTableRelation = 'employee.controller.ts';
+const controllerFileNameForMultipleRelations = 'task-employee.controller.ts';
 const repositoryFileName = 'order.repository.ts';
 const repositoryFileNameForSameTableRelation = 'employee.repository.ts';
 // speed up tests by avoiding reading docs
@@ -497,4 +498,52 @@ describe('lb4 relation', /** @this {Mocha.Suite} */ function () {
       });
     },
   );
+
+  context(
+    'checks if the controller file created for multiple relations',
+    () => {
+      const promptArray = [
+        {
+          relationType: 'belongsTo',
+          sourceModel: 'Task',
+          destinationModel: 'Employee',
+          relationName: 'createdBy',
+        },
+        {
+          relationType: 'belongsTo',
+          sourceModel: 'Task',
+          destinationModel: 'Employee',
+          relationName: 'assignedTo',
+        },
+      ];
+      promptArray.forEach(function (multiItemPrompt) {
+        describe('answers ' + JSON.stringify(multiItemPrompt), () => {
+          suite(multiItemPrompt);
+        });
+      });
+      function suite(multiItemPrompt) {
+        before(async function runGeneratorWithAnswers() {
+          await sandbox.reset();
+          await testUtils
+            .executeGenerator(generator)
+            .inDir(sandbox.path, () =>
+              testUtils.givenLBProject(sandbox.path, {
+                additionalFiles: SANDBOX_FILES,
+              }),
+            )
+            .withOptions(options)
+            .withPrompts(multiItemPrompt);
+        });
+        it('checks controller content with belongsTo relation for multiple relations', async () => {
+          const filePath = path.join(
+            sandbox.path,
+            CONTROLLER_PATH,
+            controllerFileNameForMultipleRelations,
+          );
+          assert.file(filePath);
+          expectFileToMatchSnapshot(filePath);
+        });
+      }
+    },
+  );
 });