Usage error printing during script snapshot creation (first run only)

[jakemac53]

See this travis failure https://travis-ci.org/github/dart-lang/build/jobs/698366117#L289.

To reproduce you can check out the build repo, change to the build_modules directory, and run this command dart $(pub run build_runner generate-build-script) test, which prints:

Cannot specify arguments before a command.
Usage: dart [<vm-flags>] <command|dart-file> [<arguments>]
...

You can keep reproducing it by deleting the snapshot created for build_runner under .dart_tool/pub/.

If you separate the command into two separate lines it does work as expected:

pub run build_runner generate-build-script
dart .dart_tool/build/entrypoint/build.dart test

[natebosch]

This is because the command that dart sees is effectively dart Precompiling test or something along those lines.

[jakemac53]

Oh right, that totally makes sense. Did this change from printing on stdout vs stderr or something possibly?

[sigurdm]

The precompilation message should only be printed if there is an attached terminal. Looks like I broke that with the latest refactor.