Add support for nullsafety

[vanlooverenkoen]

I am upgrading my package (Kiwi) gbtb16/kiwi#51

But it seems that build & build_runner is not yet migrated to support nullsafety. Is there a timeline on when this could be added?

[jakemac53]

We are blocked for a while on upstream dependencies, namely analyzer.

Once we are unblocked we will migrate, but there is no timeline right now.

[vanlooverenkoen]

Alright thanks. :) I already created some tickets for some dart-lang packages. So we can track this.

[jakemac53]

Ya, analyzer itself has a lot of deps as well, we have been working on migrating those though. But they have a large and very legacy codebase (originally ported from Java) so its going to be..... something to migrate it 🤣

[vanlooverenkoen]

@jakemac53 do you know if ther already is a ticket for tracking the nullsafety support for analyzer? otherwise we can link these tickets together. If not I will create a new ticket

[jakemac53]

It is being tracked somewhere, but I think not in a github issue (that team doesn't use them for tracking generally afaik). It definitely doesn't hurt to file one though so its easier to be notified when it is completed, and I can link it on a separate tracking sheet we have so hopefully it does get closed when the migration finishes.

[vanlooverenkoen]

Alright prefect I will create another one

[vanlooverenkoen]

Blocked because of: dart-lang/sdk#44290

[mnordine]

This is really too bad. I'm guessing there's a ton of packages/apps blocked on this, including our own, ☹️

[jakemac53]

Note that this does not block builders from generating null safe code (these already exist actually).

It blocks the build script from running with sound null safety, and blocks code generators from migrating their generator code.

That is a long way of saying that this doesn't need to block applications which use generated code.

[mnordine]

We're using a library that uses build_runner and build_web_compilers, and we use them in our app as well (convert yaml to json). Where does that leave us? I'm getting analyzer static errors due to build_runner

[jakemac53]

We're using a library that uses build_runner and build_web_compilers, and we use them in our app as well (convert yaml to json).

I don't understand fully the situation here - you generally wouldn't have imports of these libraries within your app. If you do, then that will be blocked until we can migrate.

Code generators should generally be split up into two libraries - one for the generator (only imported by the build script), and one for any runtime libs which should not import package:build, package:analyzer, etc.

The runtime libs can be migrated at any time in that case, and unblock migrating apps. The build time libs will be blocked on this issue.

[jakemac53]

It might be good to also clarify that you can opt out individual libs using a language version comment before any declarations in your file:

// @dart=2.9

So that would need to be used in order to opt out the generator libs.

[mnordine]

On a phone, but I will clarify later today

[vanlooverenkoen]

@jakemac53 yes indeed. For kiwi only the generator needs to be updated. So I will have to wait