Provide test helpers to ensure build-users commit files w/ build already run

[kevmoo]

See https://github.com/dart-lang/json_serializable/blob/example/json_serializable/test/ensure_build_test.dart

Maybe a no-opt build mode that (instead of writing files) makes sure that the target file exists and has the content that would be written?

Or just an easy way to run build and see changed files?

[natebosch]

Along with #718 what about parsing an arg --assert-up-to-date or similar and exit(1) if the outputs are stale?

[kevmoo]

I really don't like calling exit(...) except for the top-most script.

Or we just set exitCode and we're super clear about that...

[natebosch]

we could have run return a Future that completes with an error code?

[kevmoo]

...sure?

exitCode = await run(...)

Not too bad...

[jakemac53]

in the case of watch mode it isn't clear what the exit code should be though.... it could be based on the final build I guess?

[kevmoo]

in the case of watch mode it isn't clear what the exit code should be though.... it could be based on the final build I guess?

watch ends on ctrl-c or crash, right?

Don't you send negative exit codes for signals?

I'd guess watch would never end in 0

[jakemac53]

I'd guess watch would never end in 0

I think today it we exit with a 0 or 2 if you ctrl-c - 0 if you let it properly shut down and a 2 if you hit ctrl-c more than once and we shut down in the middle of a build.

Maybe neither of those are really correct though.

[matanlurey]

Is this really important right now @kevmoo? json-serializable is not on our OKRs.

[jakemac53]

This is important for users that are committing their generated files, and it should be relatively trivial to expose.

[kevmoo]

Is this really important right now @kevmoo? json-serializable is not on our OKRs.

Not at all. Just filing issues as I find problems.

We've now copied it a third time, though - dart-lang/pub-dev@7966dc3