Filter out the builders which "applies_builders" some builder which is "build_to: source" on non root packages

[natebosch]

Today we filter out builders that won't work because they want to build to source and auto apply to some package other than the root. Once source_gen adds the combining builder the actual builder doing work would be build_to: cache and so would get needlessly run.

cc @kevmoo - we'll want this before launching the combining builder stuff because it will impact performance.

Blocking dart-lang/source_gen#319

[kevmoo]

Yes, please!

…

On Fri, Jun 15, 2018 at 5:49 PM Nate Bosch ***@***.***> wrote: Today we filter out builders that won't work because they want to build to source and auto apply to some package other than the root. Once source_gen adds the combining builder the actual builder doing work would be build_to: cache and so would get needlessly run. cc @kevmoo <https://github.com/kevmoo> - we'll want this before launching the combining builder stuff because it will impact performance. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#1578>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AABCitYff3ZuVuP0p-wGuodKG4ScaO3Hks5t9FYMgaJpZM4UqSxi> .

[jakemac53]

This could also be resolved by allowing boolean-selector type logic to auto-apply - in this case we would want root_package && dependents. That way it would only apply to the root package, and only if that also had an explicit dependency.

Imo this is a better solution as it more directly describes the intent.

[kevmoo]

OMG – 2 users! https://pub.dartlang.org/packages?q=dependency%3Aboolean_selector