Stale package `tools/dart2js/sourceMapViewer`

[lrhn]

The directory toos/dart2js/sourceMapViewer contains a pubspec.yaml which isn't read by the SDK tools/generate_package_config.dart script and isn't valid for any modern Pub (no min-SDK constraint).
It's a dead config.

The bin/ directory script has dependencies on the http_server and router packages which are not in the SDK and not in the SDK DEPS, so they're not available by default.

That means that the script can't run, and Pub can't run to fetch its dependencies.
It's effectively dead code which cannot run.

The directory should either be brought up to date, or it should be deleted. (I'm guessing the latter.)

[sigmundch]

The source-map viewer is a tool used by the team to help diagnose issues in generated source-maps. We first introduced it when overhauling the source-maps in dart2js more than 5 years ago, but it has proven to be useful multiple times, and I recall @nshahan used it recently too.

My preference is not to delete it. That said, the dependencies here are not an SDK dependency by itself. This code could easily live outside the SDK repo without issue, but we placed it here for our convenience.

[biggs0125]

Thanks for the context, Siggi. Do you know if the neighboring tools/dart2js/angular2_testing_deps or tools/dart2js/class_generator are used? Both of those seem out of date.

[sigmundch]

Yeah, both seem like we can delete. The angular2 references from the benchmarks repo was removed in 2020, so it's clearly unused.

[nshahan]

I recall @nshahan used it recently too. My preference is not to delete it.

+1 This is a useful tool for debugging problematic sourcemaps from dart2js and DDC compiled code.