Generated controllers can import unused decorators/empty constructor.

Steps to reproduce

Using the open api generator, generate a controller that does not use any request bodies or does not pass any parameters.

This can be problematic depending on the compiler options, for example having unused parameters. The same could be said for an empty parameterless constructor.

Current Behavior

The param and requestBody decorators are imported in the controller file. An empty constructor is generated.

Expected Behavior

The param and requestBody decorators should not be imported. The constructor should be omitted.

Link to reproduction sandbox

See here: https://github.com/strongloop/loopback-next/blob/72cb8aafad31588deff96fb1af6d33fa03fe5fd5/packages/cli/generators/openapi/templates/src/controllers/controller-template.ts.ejs#L2

The imports are made unconditionally.

Additional information

win32 x64 12.5.0
├─ @loopback/boot@1.4.4
├─ @loopback/context@1.20.2
├─ @loopback/core@1.8.5
├─ @loopback/http-server@1.4.4
├─ @loopback/metadata@1.2.5
├─ @loopback/openapi-v3@1.7.0
├─ @loopback/repository-json-schema@1.8.0
├─ @loopback/repository@1.8.2
├─ @loopback/rest-explorer@1.2.5
├─ @loopback/rest@1.16.3
├─ @loopback/service-proxy@1.2.5
├─ loopback-connector@4.8.0
├─ loopback-datasource-juggler@4.8.2

Related Issues

N/A

Open packages/cli/generators/openapi/templates/src/controllers/controller-template.ts.ejs, where the issue identifies unconditional imports. Generate a controller with no request bodies or parameters and inspect the emitted controller. Done means unused param/requestBody decorator imports and the empty constructor are omitted; check any generator tests covering this template if present.