Versioned 1.x and 2.x formulae for Dart 2 migration

[apjanke]

You may wish to provided versioned dart@1 and dart@2 formulae to ease the migration to the new major-version Dart 2 release.

This PR is just an example of how you could do it; I'm new to this project so I'm not sure if it fits in with your style and workflow.

The dart@2 formula would be a short-term one, kept around only until a stable Dart 2 release is out as the stable version in the main dart formula. This would support:

• Developers who need to depend on Dart 2 with their current development versions. Homebrew does not support dependencies on --devel installations/channels. Example: Dart SDK version does not satisfy the requirement sass/homebrew-sass#5
• Side-by-side installation of Dart 1 and 2 for developers who wanted to compare their behaviors.

The dart@1 formula would be a long-term fix for supporting legacy applications which have not been migrated to Dart 2.

[whesse]

The .rb files are generated by a script in the dart-lang/sdk repo, at tools/apps/update_homebrew. These scripts would need to be modified to create these new dart@1 and dart@2 files.

I'm not sure if this is worth doing at this point. We hope to release Dart 2.0 soon, so maybe we can skip this. Would Dart 1 users be able to keep using the same formula, just pinning a version? If not, maybe we can just add a dart@legacy formula.

[apjanke]

The .rb files are generated ...

Thanks. I'll have a peek at this.

We hope to release Dart 2.0 soon, so maybe we can skip this.

Probably so, at least for the dart@2 one. It's easy for app developers who really need it to define their own.

Would Dart 1 users be able to keep using the same formula, just pinning a version?

That would be pretty hard to do; Homebrew doesn't have great support for pinning particular versions, and there's no way to express that version-specific dependency in the formula DSL, so packagers of legacy apps couldn't really use it. To get it to work smoothly from an end-user perspective, it probably does have to be a separate "@"-versioned formula.

A dart@legacy formula sounds like a good idea and is basically what my dart@1 was intended to do; it's just a Homebrew convention to use numeric major versions after the "@".

[kevmoo]

@whesse – the SDK script just updates the one file, right? We could add the dart@1.rb file here and just leave it frozen in time, right?

[nex3]

FYI, this is blocking Dart Sass from upgrading to Dart 2.

[nex3]

@whesse says:

I'm on a phone without GitHub. Can you reply that we should then add both dart@1 and dart@2, and dart@2 should be updated by the script? Thanks.

[kevmoo]

Do we still have dart.rb? Is there a way that points to dart@2.rb?

Do we land dart@1.rb now then? Who owns that?

[apjanke]

In my view:

Do we still have dart.rb?

Yes. That will remain the main Dart formula. dart@1 and/or dart@2 would be special-purpose auxiliary formulae.

Is there a way [dart.rb] points to dart@2.rb?

No. They need to have different definitions: in main dart.rb, Dart 2 is still --devel until its official non-RC release. In dart@2, Dart 2 is the main stable version, so that you can define dependencies against it.

...we should then add both dart@1 and dart@2, and dart@2 should be updated by the script...

I will attempt to modify this PR to have dart@2 be generated by the script (in addition to dart.rb), instead of manually maintained.

[kevmoo]

Could we start with a super simple PR that just adds `dart@1.rb`? That seems a no-brainer.

…

On Thu, May 31, 2018 at 3:58 PM Andrew Janke ***@***.***> wrote: In my view: Do we still have dart.rb? Yes. That will remain the main Dart formula. ***@***.*** and/or ***@***.*** would be special-purpose auxiliary formulae. Is there a way [dart.rb] points to ***@***.***? No. They need to have different definitions: in main dart.rb, Dart 2 is still --devel until its official non-RC release. In ***@***.***, Dart 2 is the main stable version, so that you can define dependencies against it. ...we should then add both ***@***.*** and ***@***.***, and ***@***.*** should be updated by the script... I will attempt to modify this PR to have ***@***.*** be generated by the script (in addition to dart.rb), instead of manually maintained. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#52 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AABCijUYuVPHAnrxfWkl2Kt5IafB7XsFks5t4HWhgaJpZM4UUyYl> .

[apjanke]

Done: #53

[apjanke]

Sass has fixed their problem by becoming compatible with Dart 1.x again. The dart@1 formula has landed. Maybe we can just hold off on the rest of this unless we hear of another developer that's having trouble, since Dart 2 will go stable soon?

[nex3]

Sass needs to get into Dart 2 as soon as possible—most packages are no longer Dart 1-compatible, so we're running on borrowed time with Dart 1 compatibility. This is still high-priority.

[apjanke]

Okay.

Here's my WIP on getting a dart@2 formula generated: Branch, Code. I'm working on getting my Dart build environment set up so I can test it.

Is there any doco on how the tools/apps/update_homebrew/bin/generate.dart program is used during your release workflow? I found the program that generates the Homebrew formula files, but don't see how it is called, so I'm not sure how to test it.

[whesse]

It is called manually from the command line by the person doing the release.

…

On Fri, Jun 1, 2018, 21:20 Andrew Janke ***@***.***> wrote: Okay. Here's my WIP on getting a ***@***.*** formula generated: Branch <https://github.com/apjanke/dart-sdk/tree/generate-dart%402-homebrew-formula>, Code <apjanke/dart-sdk@0469901>. I'm working on getting my Dart build environment set up so I can test it. Is there any doco on how the tools/apps/update_homebrew/bin/generate.dart program is used during your release workflow? I found the program that generates the Homebrew formula files, but don't see how it is called, so I'm not sure how to test it. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#52 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AErap0EvFEBmlji7XRQ6zyqmoJoBHEqwks5t4ZP5gaJpZM4UUyYl> .

[apjanke]

Thanks. I will iron out my Dart build environment and test it manually.

[apjanke]

I haven't gotten my Dart environment set up right yet, but the function to generate the Homebrew formula files is super simple, so I think I might have one for you anyway: dart-lang/sdk#33318.

Closing this in favor of dart-lang/sdk#33318.