[BUG] Vendor extension is empty/ non-existent

I'm using OAS3 generator for Java as a Maven plugin to generate POJOs, controllers, delegates etc for my APIs with the Mustache templates from the openapi-generator repository: https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/resources/JavaSpring/apiController.mustache

I'm trying to edit this template so that the "@Controller" annotation is generated only if a condition is met. I've searched for multiple solutions for this and one of them was using "vendorExtensions".

I've made the following contract with x-generateController vendorExtension:

openapi: 3.0.0
info:
  title: User API
  description: API for user changes
  contact:
    name: xxx
    url: xxx
    email: xxx
  license:
    name: xxx
    url: xxx
  version: 1.0.0
tags:
  - name: user
x-generateController: True
paths:
  /users:
  ...

And then in the Mustache template file I have put the following:

{{#vendorExtensions.x-generateController}}
@Controller("{{classname}}")
{{/vendorExtensions.x-generateController}}

The generator works just fine without this condition but it seems like it doesn't take into account x-generateController. In fact, if I try to just place it as a comment like this:

// {{vendorExtensions.x-generateController}}
I get only "// " and an empty space. I've also tried putting it at the "endpoint level" and not in the "info level" and the problem is the same.

Is there anything more that I should've done in the configuration? Is there any alternative for a condition in the Mustache template?

Start with modules/openapi-generator/src/main/resources/JavaSpring/apiController.mustache and reproduce the generation using the contract's x-generateController extension at the shown levels. Compare the generated output with the Mustache expressions for vendorExtensions. Done means the documented extension is available in the relevant template context and conditionally controls the @Controller annotation.