Skip to main content

New pub package layout

Today, Bob Nystrom, one of the pub engineers, posted details about the new pub package layout. Time to use the new layout for your packages!

Bob writes:


If you live on bleeding_edge, pub now supports the new package layout conventions that avoid the nasty circular symlinks.

Pub also still supports the old style too, simultaneously. It works like this:
  1. When pub is generating a symlink to a package it determines if it's an old style or new style package. The presence of a .dart file at the top level (aside from build.dart) indicates that it's an old style package.
  2. If it's an old style package, pub symlinks to the package's root directory.
  3. If it's a new style package, it looks for a "lib" directory inside that package and symlinks to that.
  4. It will also generate a self link, but only for new style packages.
So, if you have:

myapp/
  pubspec.yaml -> depends on old_style and new_style
  lib/
    app.dart

old_style/
  old_style.dart

new_style/
  lib/
    new_style.dart

You run "pub install" on myapp, and you'll get:

myapp/
  pubspec.yaml -> depends on old_style and new_style
  lib/
    app.dart
  packages/
    myapp/ -> symlink to myapp/lib/
      app.dart
    old_style/ -> symlink to old_style/
      old_style.dart
    new_style/ -> symlink to new_style/lib/
      new_style.dart

Note that inside packages/ everything looks like you want and your imports should be unchanged. What this means is that if some package you depend on migrates from the old to the new style, it's shouldn't affect you. The next time you update that package, it will magically do the right thing.

All of the SDK packages that come with Dart are still using the old style, but we'll be updating those over the next couple of weeks. Around M1, I will remove support for the old layout. If you haven't updated your package by then, it will stop working.

Let me know if you have questions/comments/complaints/sonnets. You can read more about the pub package layout recommendation.


As always, you can join the discussion at the Dart mailing list, and post questions to Stack Overflow.

Popular posts from this blog

Dart in 2016: The fastest growing programming language at Google, 2nd fastest growing in TIOBE Index

Dart was the fastest growing programming language at Google in 2016 with millions of lines of code written. It also made it to TIOBE Index Top 20 this month (see TIOBE's methodology).

It takes time to build something as ambitious as Dart and, in some ways, Dart is still in its infancy. But we're glad the hard work is starting to pay off.

Many thanks to our amazing community!

We're going to celebrate by ... releasing 1.22 next week (as per our usual 6 week release schedule).

A stronger Dart for everyone

We are constantly asking ourselves:
How do we make developers even more productive when writing Dart apps? We believe that a critical part of the answer to this question is to make strongmode – a sound static type system for Dart – the standard for all Dart developers.

Teams that use Dart to build apps like Soundtrap, AdWords, AdSense, and Greentea say they really enjoy using strong mode features, such as early error detection. In fact, teams that have switched completely to strong mode cite not only early error detection but also better code readability and maintainability as major benefits. We hear this both from small teams and Рeven more so Рfrom large teams with hundreds of developers writing and maintaining millions of lines of Dart code. As Björn Sperber from Soundtrap says,
Strong mode and the smooth integration with IntelliJ is a joy to use and a huge improvement. If you’ve tried out Flutter, you’ve already used strong mode checks from the Dart analyzer.

Given the benefits …

AngularDart 3.0: Easy upgrade, better performance

AngularDart 3.0 is now available. It brings better performance and smaller generated code, while also making you more productive.


Version 3.0 is an evolution: although it has some breaking changes (detailed below), it is a smooth upgrade due to minimal public API adjustments. Most of the progress is under the hood—in code quality, stability, generated code size, performance, and developer experience.

Code quality:
2731 instances of making the framework code more type safe (using sound Dart).The AngularDart framework code size is down by 12%.Many additional style updates to the codebase:Changed to use idiomatic <T> for generic methods.Removed NgZoneImpl, all the code exists in NgZone now.Stability:
Many CSS encapsulation fixes due to update with csslib package.Fixed bugs with IE11.

Performance:
For the Mail sample app, we see 30% faster time-to-interactive (currently 3812 ms on a simulated 3G connection, measured via Lighthouse).Our large app benchmark shows 2x faster render times of…