Support running node_interop in null safety mode

[Awjin]

This allows downstream users to start migrating their packages to null safety.

[pulyaevskiy]

Thanks! LGTM, just a minor comment in pubspec. Please take a look.

[Awjin]

Looks like this is breaking the e2e test that invokes build_runner (which does not have a null-safe version available).

[pulyaevskiy]

Looks like this is breaking the e2e test that invokes build_runner (which does not have a null-safe version available).

@Awjin

Build on stable fails because it runs on Dart 2.10.x and we've updated SDK constraint here.
Build on dev fails for multiple reasons. There seems to be an issue with build_node_compilers as well as in node_interop. I suspect e2e test fails because of the first one.

The node_interop one seems to be easy to fix, it's just a lint:
https://travis-ci.org/github/pulyaevskiy/node-interop/jobs/748668797#L557

We may need to look at fixing build_node_compilers first before landing this change...

[jathak]

build_node_compilers probably can't be migrated to null-safety until build (and other related packages) are, and it's blocked on analyzer being migrated, which is apparently not happening until March at the earliest.

This shouldn't block migrating packages that only use build_node_compilers as a dev dependency though. Looking into this now...

[jathak]

Dart 2.12 was released as stable this morning, so I'm going to check again to see if we can migrate without waiting on build. If not, it hopefully won't be a blocker for long, since analyzer's now been migrated and it looks like the build packages are being actively worked on.

[Awjin]

Ok, I've worked around all of the breakages. build_node_compilers works now—a deeper fix requires migrating it to nnbd, which is blocked on build migrating first.

@pulyaevskiy WDYT about releasing this first, then migrating build_node_compilers once it's possible to do so? This would unblock Dart Sass's migration to nnbd.

[pulyaevskiy]

LGTM, thanks.

[pulyaevskiy]

Just сurious - is this a new addition in build package?

[Awjin]

Yes, this is a new placeholder added in build_runner

[pulyaevskiy]

@Awjin sorry for the delay here.

WDYT about releasing this first, then migrating build_node_compilers once it's possible to do so? This would unblock Dart Sass's migration to nnbd.

This makes sense to me. Will merge this and publish a new version.

Thanks for working on this!

[Awjin]

@pulyaevskiy Thanks for the review and merge! Would you be able to release a new version as well?