Migrate to `dart install`

[mit-mit]

We should migrate webdev to use dart install instead of dart pub global activate. The new install command should make webdev faster (it does an AOT compile), and we'd like to deprecate dart pub global activate.

I tried simply switching things over, but it looks like tests fail.

There's also an issue here: #2758

[mit-mit]

cc @kevmoo

[dcharkes]

What is the typical way to run webdev?

1. Executable placed on PATH: webdev <...>
2. Last published version from pub, evergreen: dart run webdev@
3. A version selected via the pubspec dev dependencies and possibly pinned via a pubspec lock: dart run webdev

I feel like you'd want to pin webdev as a dev dependency (option 3)? In that case, you'd never dart install it. But maybe I'm not very aware of typical user journey of devs using webdev.

[mit-mit]

Today it's a global activate: https://dart.dev/tools/webdev#installing-and-updating-webdev

But I don't know enough of the history as to why that as (as opposed to say the dev dependency + dart run webdev). Maybe @kevmoo or @sigmundch can shed some light?

[jakemac53]

I can't remember for sure, but one reason to keep it as a globally activated/installed packages is that webdev has a LOT of dependencies. If we told people to depend on it as a dev dependency, those would become a part of their packages version solve and it would likely increase the possibility of incompatible version constraints quite a bit. It also would increase the urgency around widening dependency constraints when breaking versions of the various deps are released, where today we can do that at our own leisure as there is little to no impact to consumers of the package if we are on some old versions of deps.

[sigmundch]

cc @natebiggs

If I remember correctly, another constraint was the tight coupling webdev has with the SDK. Some internal dependencies, like dwds/vmservice, are co-developed with SDK changes and often force us to update them in lockstep.

Webdev still asks for dev dependencies from users on the build-runner/build-web-compiler packages, though. Those have much a more stable evolution story and a clear contract with the rest of webdev.

[biggs0125]

IIRC there was an issue with dart install around getting access to the SDK files. When webdev is serving dev code it tries to pull assets out of the SDK. When it's running in AOT mode I think we don't have a well-defined SDK location so webdev doesn't know where to get those assets.

I'm not sure how dependent webdev itself is on a specific version of the SDK. But I think there might be some dependency on DWDS which is itself dependent on the internals of the SDK.

[kevmoo]

Yep! I have a bunch of code that uses Platform.resolvedExecutable that now...doesn't work.

Tracking issue: dart-lang/sdk#63210