# Flutter Conductor

Command-line tool for managing a release of the Flutter SDK. Also see
https://github.com/flutter/flutter/wiki/Release-process for more information on
the release process.

## Requirements

Some basic requirements to conduct a release are:

- a Linux or macOS computer set up for Flutter development. The conductor does
  not support Windows.
- git
- Mirrors on GitHub of the Flutter
  [framework](https://github.com/flutter/flutter) and
  [engine](https://github.com/flutter/engine) repositories.

For the best experience, it is recommended to use ssh protocol for connecting to
GitHub remote repositories (i.e. for `--framework-mirror` and `--engine-mirror`
specify the remote with the format `git@github.com:username/reponame`). If your
local ssh key is password-protected, it is recommended to use ssh-agent to
unlock your ssh key for the session; if you do not, each time the conductor
attempts to interact with a remote, the user will be prompted to enter their ssh
key password.

## Usage

The main entrypoint for the conductor is [bin/conductor](bin/conductor). For
brevity, the rest of this document will assume that this entrypoint is on the
shell path.

All available commands can be seen via:

`conductor help`

Releases are initialized with the `start` sub-command, like:

```
conductor start \
  --candidate-branch=flutter-2.2-candidate.10 \
  --release-channel=beta \
  --github-username=kingOfDevelopers \
  --engine-cherrypicks=72114dafe28c8700f1d5d629c6ae9d34172ba395 \
  --framework-cherrypicks=a3e66b396746f6581b2b7efd1b0d0f0074215128,d8d853436206e86f416236b930e97779b143a100 \
  --dart-revision=4511eb2a779a612d9d6b2012123575013e0aef12 \
```

The conductor will, based on the release channel and the presence/lack of
previous tags, determine which part of the release version should be
incremented. In the cases where this is not correct, the version can be
overridden with `--version-override=3.0.0`.

For more details on these command line arguments, see `conductor help start`.
This command will write to disk a state file that will persist until the release
is completed. If you already have a persistent state file, this command will
fail with an error message. To see the current status of the release (at any
time), issue the command:

`conductor status`

To delete a persistent state file (either because the release was successfully
completed or abandoned), use the command:

`conductor clean`

Once initializing the release, the conductor tool will issue instructions for
manual steps that must be executed by the user. At any time these instructions
can be seen via `conductor status`. Once these manual steps have been completed,
you can proceed to the next step by using the command:

`conductor next`

## Steps

Once the user has finished manual steps for each step, they proceed to the next
step with the command:

`conductor next`

### Apply Engine Cherrypicks

The tool will attempt to auto-apply all engine cherrypicks. However, any
cherrypicks that result in a merge conflict will be reverted and it is left to
the user to manually cherry-pick them (with the command `git cherry-pick
$REVISION`) and resolve the merge conflict in their checkout.

Once a PR is opened, the user must validate CI builds. If there are regressions
(or if the `licenses_check` fails, then
`//engine/ci/licenses_golden/licenses_third_party` must be updated to match the
output of the failing test), then the user must fix these tests in their local
checkout and push their changes again.

### Apply Framework Cherrypicks

The tool will attempt to auto-apply all framework cherrypicks. However, any
cherrypicks that result in a merge conflict will be reverted and it is left to
the user to manually cherry-pick them (with the command `git cherry-pick
$REVISION`) and resolve the merge conflict in their checkout.

### Publish Version

This step will add a version git tag to the final Framework commit and push it
to the upstream repository. The presence of a tag affects what the flutter CLI
tool reports the current version is.

### Publish Channel

This step will push the Framework candidate branch to the upstream release
branch (e.g. the `stable` branch). Once this push happens upstream, the release
has officially been published, and the code will be available to existing
Flutter users via `flutter upgrade`.

### Verify Release

For the final step, the user must manually verify that packaging builds have
finished successfully. The SDK compressed archives will not be available from
the website until the packaging build has finished. The conductor will produce
links to the dashboards for monitoring CI builds.
