How run flutter 'packages pub run build_runner build' with debug mode in intellij idea?

Question

I want to put break point on my generator code, but I don't know how to run the command on the debug mode.

I wrote generator using source_gen and build_runner

class MyGenerator extends GeneratorForAnnotation<Todo> {
  @override
  FutureOr<String> generateForAnnotatedElement(
      Element element, ConstantReader annotation, BuildStep buildStep) {
    return "// Hey! Annotation found!";
  }
}

Answer 1

1. run commad flutter packages pub run build_runner build*

2. copy build.dart to root folder of project

3. add new run configuration
4. run debug, now you can debug your code generator!

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* the packages is optional, you can just run flutter pub run build_runner build