Zulip Flutter (beta)

A Zulip client for Android and iOS, using Flutter.

This app is currently in beta. When it's ready, it will become the new official mobile Zulip client. To see what work is planned before that launch, see the milestones and the project board.

Using Zulip

To use Zulip on iOS or Android, install the official mobile Zulip client.

You can also try out this beta app.

Contributing

Contributions to this app are welcome.

If you're looking to participate in Google Summer of Code with Zulip, this is one of the projects we're accepting GSoC 2024 applications for.

Picking an issue to work on

First, see the Zulip project guide to your first codebase contribution. Follow the instructions there for joining the Zulip community server, reading about what makes a great Zulip contributor, browsing through recent commits and the codebase, and the Zulip guide to Git.

To find possible issues to work on, see our project board. Look for issues up through the "Launch" milestone, and that aren't already assigned.

Follow the Zulip guide to picking an issue to work on, trying several issues until you find one you're confident you'll be able to take on effectively.

After you've done that, claim the issue by posting a comment on the issue thread, saying you'd like to work on it and describing your progress.

Submitting a pull request

Follow the Zulip project's guide to your first codebase contribution for working on an issue and submitting a pull request. It's important to take the time to make your work as easy as possible for others to review.

Two specific points to expand on:

Before we can review your PR in detail, your changes will need tests. See "Writing tests" below.

It will also need all new and existing tests to be passing. See "Tests" below about running the tests.
Your changes will need to be organized into clear and coherent commits, following Zulip's commit style guide.

This is always required before we can merge your PR. Depending on your changes' complexity, it may also be required before we can review it in detail. (The main exception is that if the change should be a single commit, we can review it even with a messier commit structure.)

Getting started in developing this beta app

Setting up

Follow the Flutter installation guide for your platform of choice.
Switch to the latest version of Flutter by running flutter channel main and flutter upgrade (see Flutter version below).
Ensure Flutter is correctly configured by running flutter doctor.
Start the app with flutter run, or from your IDE.

Flutter version

While in the beta phase, we use the latest Flutter from Flutter's main branch. Use flutter channel main and flutter upgrade.

We don't pin a specific version, because Flutter itself doesn't offer a way to do so. So far that hasn't been a problem. When it becomes one, we'll figure it out; there are several tools for this in the Flutter community. See issue #15.

Tests

You can run all our forms of tests with the tools/check script:

$ tools/check

See tools/check --help for more information.

The two major test suites are the Dart analyzer, which performs type-checking and linting; and our unit tests, located in the test/ directory.

You can run these suites directly with the commands flutter analyze and flutter test respectively. Both commands accept a list of file or directory paths to operate on, and other options. Particularly recommended is a command like

$ flutter test test/foo/bar_test.dart --name 'baz'

which will run only the tests in test/foo/bar_test.dart, and within those only the tests with names matching baz.

When editing in an IDE, the IDE should give you the exact same feedback as flutter analyze would. When editing a test file, the IDE can also run individual tests for you. See upstream docs on flutter test.

Notes

Writing tests

We write tests for all changes to the Dart code in the app. Because Flutter and Dart have excellent facilities for testing, we're able to efficiently write tests even for kinds of code that often go untested: UI code, and code that makes network requests or calls external APIs.

You may sometimes find code that doesn't have tests. This is generally code from the early prototype phase; when we make changes to it, we write tests for the changes, and often take the opportunity to write tests for the existing logic too.

When it's time to write a test, look around at existing tests in the same test file or at our existing tests for similar code, and follow the patterns we use there. Notes on specific kinds of tests:

For UI code, we use Flutter's standard testWidgets function. Many widgets will interact with the user's data; see docs on our TestZulipBinding and TestGlobalStore, and existing tests that use testBinding.globalStore, for how to manipulate test data there.
For code that makes Zulip API requests, use FakeApiConnection; see its docs and the existing tests that use it.
For code that makes other network requests, look for similar existing tests; or see our FakeHttpClient, and use withHttpClient from package:http to cause the code under test to use it.
For code that invokes Flutter plugins or otherwise calls external APIs, see our ZulipBinding class. If there isn't an existing member of that class that wraps the API you're using, then you'll need to add one; follow the existing examples.

`check` vs. `expect`

For our tests, we use the checks package. This is a new package from the Dart team, currently in preview, which is intended to replace the old matcher package.

This means that if you see example test code elsewhere that uses the expect function, we'd prefer to translate it into something in terms of check. For help with that, see the package:checks migration guide and the package's API docs.

Because package:checks is still in preview, the Dart team is open to feedback on the API to a degree that they won't be after it reaches 1.0. So where we find rough edges, now is a good time to report them as issues.

Editing API types

We support Zulip Server 4.0 and later. For API features added in newer versions, use TODO(server-N) comments (like those you see in the existing code.)

When editing the files in lib/api/model/, use the following command to keep the generated files up to date:

$ dart run build_runner watch --delete-conflicting-outputs

In our API types, constructors should generally avoid default values for their parameters, even null. This means writing e.g. required this.foo rather than just this.foo, even when foo is nullable. This is because it's common in the Zulip API for a null or missing value to be quite salient in meaning, and not a boring value appropriate for a default, so that it's best to ensure callers make an explicit choice. If passing explicit values in tests is cumbersome, a factory function in test/example_data.dart is an appropriate way to share defaults.

Upgrading Flutter

We regularly increment our lower bounds on Flutter and Dart versions, to make sure there's not too much divergence in the versions people are using.

When there's a new beta (which happens a couple of times per month), that's a good prompt to do this. We also do this when there's a new PR merged that we particularly want to take.

To update the version bounds:

Use flutter upgrade to upgrade your local Flutter and Dart.
Update the lower bounds at environment in pubspec.yaml to the new versions, as seen in flutter --version.
Run flutter pub get, which will update pubspec.lock.
Make a quick check that things work: tools/check, and do a quick smoke-test of the app.
Commit and push the changes in pubspec.yaml and pubspec.lock.

Upgrading dependencies

When adding or upgrading dependencies, try to keep our generated files updated atomically with them.

In particular the CocoaPods lockfiles ios/Podfile.lock and macos/Podfile.lock frequently need an update when dependencies change. This can only be done in a macOS development environment.

If you have access to a Mac, then for upgrading dependencies, use the script tools/upgrade. Or after adding a new dependency, run the commands (cd ios && pod update) && (cd macos && pod update) to apply any needed updates to the CocoaPods lockfiles.

If you don't have convenient access to a Mac, then just mention clearly in your PR that the upgrade needs syncing for CocoaPods, and someone else can do it before merging the PR.

(Ideally we would validate these automatically in CI: #329. Several other kinds of generated files are already validated in CI.)

Code formatting

Like the upstream Flutter project itself, we don't use dart format or other auto-formatters. Instead, follow the style you see in the existing code.

It's OK if in your first few PRs you haven't yet picked up all the nuances of our style. Reviewers will point out nits as they see them.

If your editor or IDE automatically reformats the existing code, you'll want to turn that off. Please also mention it in Zulip on chat.zulip.org and describe what editor you were using; we'd like to include such configuration directly in the repo so it's automatic for the next person. We already have that for VS Code, and it seems to be the default for Android Studio / IntelliJ, but when there are cases we haven't covered we'd like to know about them.

Translations and i18n

When adding new strings in the UI, we set them up to be translated. For details on how to do this, see the translation doc.

License

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.

The software includes some works released by third parties under other free and open source licenses. Those works are redistributed under the license terms under which the works were received.

chrisirhc/zulip-flutter