dwds/CONTRIBUTING.md

## Local Development

### With Flutter tools (recommended)

1. Fork and download the [Flutter repo](https://github.com/flutter/flutter).
   Detailed instructions can be found
   [here](https://github.com/flutter/flutter/wiki/Setting-up-the-Framework-development-environment).
1. Add an alias to your `.bashrc`/`.zshrc` for Flutter Tools:

```
alias flutter_tools='/YOUR_PATH/flutter/bin/dart --observe /YOUR_PATH/flutter/packages/flutter_tools/bin/flutter_tools.dart'
```

> **Explanation:**
>
> - `/PATH_TO_YOUR_FLUTTER_REPO/bin/dart`: This is the path to the Dart SDK that
>   Flutter Tools uses
> - `--observe`: This flag specifies we want a Dart DevTools URL for debugging
> - `/PATH_TO_YOUR_FLUTTER_REPO/packages/flutter_tools/bin/flutter_tools.dart`:
>   This is the path to Flutter Tools itself
>
> *More details can be found at the Flutter Tools
> [README](https://github.com/flutter/flutter/blob/master/packages/flutter_tools/README.md).*

3. In your Flutter Tools
   [`pubspec.yaml`](https://github.com/flutter/flutter/blob/master/packages/flutter_tools/pubspec.yaml),
   change the DWDS dependency to point to your local DWDS:

```
  dwds:
    path: /YOUR_PATH/dwds
```

4. Choose a Flutter app to run (eg, the
   [old](https://github.com/flutter/flutter/tree/master/dev/integration_tests/flutter_gallery)
   or [new](https://github.com/flutter/gallery) Flutter Gallery apps).
1. From the Flutter app repo, run your local Flutter Tools with alias you
   defined in step #2:

```
flutter_tools run -d chrome
```

6. Open up the **first** Dart DevTools URL you see printed:

```
...
The Dart VM service is listening on http://127.0.0.1:8181/ajXIPMLq6iI=/
The Dart DevTools debugger and profiler is available at: http://127.0.0.1:8181/ajXIPMLq6iI=/devtools/#/?uri=ws%3A%2F%2F127.0.0.1%3A8181%2FajXIPMLq6iI%3D%2Fws   <== THIS ONE!
Launching lib/main.dart on Chrome in debug mode...
...
```

7. The Dart DevTools you open is connected to your Flutter Tools, but because of
   the path dependency added in step #3, you can debug your local DWDS as well.

### With WebDev

Follow instructions in the `webdev/example` [README](/example/README.md) to run
the example app and connect to DWDS.

## Changes required when submitting a PR

- Make sure you update the `CHANGELOG.md` with a description of the change
- If DWDS / Webdev was just released, then you will need to update the version
  in the `CHANGELOG`, and the `pubspec.yaml` file as well (eg,
  https://github.com/dart-lang/webdev/pull/1462)
- For any directories you’ve touched, `run dart run build_runner` build to check
  in the any file that should be built. This will make sure the integration
  tests are run against the built files.

## Release steps

### Step 1: Roll DWDS into g3

> *NOTE: You must be a Googler to do this step. If you are not, please ask
> someone for help.*

- See directions at: go/roll-dwds
- Wait a few days after rolling into g3 before continuing to step 2. We do so to
  have time to catch new bugs internally before publishing externally. Look for
  any new exceptions at go/ddt-web-dashboard

## Step 2: Publish DWDS to pub

- Make sure you are on the Dart stable SDK version (check with `dart --version`)
- From each of the subdirectories (`/dwds`, `/frontend_server_client`,
  `/frontend_server_common`, and `/webdev`) update dependencies with
  `dart pub upgrade`
- Update the version number in `dwds/pubspec.yaml` and `dwds/CHANGELOG.md`
- From `/dwds` run `dart run build_runner build`, this will build and update the
  version in `/dwds/lib/src/version.dart`
- Submit a PR with those changes (example PR:
  https://github.com/dart-lang/webdev/pull/1456). *Note: Ensure your PR doesn’t
  have any dependency overrides.*
- Once the PR is submitted, pull from master and `run dart pub publish`
- Finally, go to https://github.com/dart-lang/webdev/releases and create a new
  release, eg https://github.com/dart-lang/webdev/releases/tag/dwds-v12.0.0. You
  might need to delete some of the content of the autogenerated notes.

> *Note: To have the right permissions for publishing, you need to be invited to
> the tools.dart.dev. A member of the Dart team should be able to add you at
> https://pub.dev/publishers/tools.dart.dev/admin.*

## Step 3: Publish Webdev to pub

> *Note: DWDS is a dependency of Webdev, which is why DWDS must be published
> before Webdev can be published.*

Follow instructions in the `webdev/webdev`
[CONTRIBUTING](/webdev/CONTRIBUTING.md) to release Webdev.

## Whenever the Dart SDK is updated

Whenever Dart SDK is updated to a new major or minor version (~every 2 weeks),
any PR submissions to Webdev are blocked by the min_sdk_test until the Dart min
SDK constraint is updated. Therefore, whenever your PR gets blocked by the test,
you need to:

1. Create a new PR that updates all the min SDK constraints to the new version,
   eg: https://github.com/dart-lang/webdev/pull/1463.
1. From each of the subdirectories (`/dwds`, `/frontend_server_client`,
   `/frontend_server_common`, and `/webdev`) update dependencies with
   `dart pub upgrade`
1. Make sure to update the `CHANGELOG` to include the new version number
1. Submit your PR. At this point, you technically will be able to submit the PR
   that was blocked, but the point of the test is to make sure that DWDS and
   Webdev get released after a Dart stable release. Therefore, follow the steps
   above to publish DWDS and Webdev.

> ### Why is this necessary?
>
> This is so that we don’t need to support older versions of the SDK and test
> against them, therefore every time the Dart SDK is bumped to a new major or
> minor version, DWDS and Webdev’s min Dart SDK constraint needs to to be
> changed and DWDS and Webdev have to be released. Since DWDS is dependent on
> DDC and the runtime API, if we had a looser min constraint we would need to
> run tests for all earlier stable releases of the SDK that match the
> constraint, which would have differences in functionality and therefore need
> different tests.