Notify build_runner of Dependency on API Spec

[PvtPuddles]

Description of the bug

There is a work-around in-place for the Openapi annotation: forceAlwaysRun.

From the docs:

If true, the annotated file will be modified after code generation completes.

This is a workaround to ensure this library runs every time you execute the build_runner command.

Why modify the file?

build_runner only processes files that have changed since the last run. By modifying the file, you force build_runner to recognize it as changed and re-run the generation process.

Note: Setting this to true can lead to merge conflicts in team environments, as each developer may end up modifying the annotated file.

It is not necessary to run the builder every time build_runner is called; users only need to run it when the API spec changes.

If the spec file can be loaded by build_runner (IE: the spec file is in the lib directory of the annotated package), the builder should notify build_runner the file is read. See this discussion.

Steps to reproduce

To reproduce the issue, use the Openapi annotation and make sure forceAlwaysRun is set to false.

Modify the API Specification and run dart run build_runner build -d. Observe that the Openapi generator is not run.

Minimal openapi specification

N/A

Annotation used

@Openapi(
  additionalProperties: DioProperties(
    pubName: "my_package",
    pubAuthor: "myself",
  ),
  generatorName: Generator.dio,
  inputSpec: InputSpec(path: 'lib/src/services/mp_package/my-open-api.yml'),
  outputDirectory: 'generated/my_package',
  forceAlwaysRun: false,
  skipIfSpecIsUnchanged: false,
)

Expected behavior

The generator should be re-run every time my-open-api.yml is modified, without having to update the "Generator last run: ..." timestamp.

Logs

Screenshots

No response

Platform

macOS

Library version

6.1.0

Flutter version

3.29.2

Flutter channel

stable

Additional context