Samuel Susla
dffec8bc7b
Summary: Changelog: [internal] In D22940187 (https://github.com/facebook/react-native/commit/774dec1e17f6f250172a6d4d944121b82fa36efb) we introduced a mechanism to retry failed state updates from view layer. The mechanism fixes an issue where state update is occasionally dropped with background executor enabled. # Why is state dropped? The state is dropped because with background executor enabled, it is possible to enter `ShadowTree::tryCommit` for the same tree from 2 different threads at once. One of thread changes `_rootShadowNode` causing the other commit to fail. The code goes like this: ``` { Lock mutex grab reference to `rootShadowNode_` and call it `oldRootShadowNode` Unlock mutex } State reconciliation Trigger layout `rootShadowNode_` is untouched in this section. { Lock mutex Check if `oldRootShadowNode` is equal to `rootShadowNode_`, if not, return false signalling failure. Now this is what happens when state update fails. ..... not relevant Unlock mutex } ..... not relevant ``` However, in D22940187 (https://github.com/facebook/react-native/commit/774dec1e17f6f250172a6d4d944121b82fa36efb), we have taken another path. Instead of retrying to commit transaction, client is informed about the failure and it is left up to them to retry. This is correct and works. But I think it is unnecessary to this retry can be done inside UIManager::updateState. In this diff I call `ShadowTree::commit` (version with retries) in case no `stateUpdate.failureCallback` is provided. This makes sure that we do retry if state update fails but if Android implements `stateUpdate.failureCallback`, it is left up to view layer to retry. Eventually we might decide to converge these two approaches. Reviewed By: shergin Differential Revision: D23151218 fbshipit-source-id: 5cb78a3a75a754429a8e33bd7736e683e9ed34d4
React Native
Learn once, write anywhere:
Build mobile apps with React.
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React Native brings React's declarative UI framework to iOS and Android. With React Native, you use native UI controls and have full access to the native platform.
- Declarative. React makes it painless to create interactive UIs. Declarative views make your code more predictable and easier to debug.
- Component-Based. Build encapsulated components that manage their state, then compose them to make complex UIs.
- Developer Velocity. See local changes in seconds. Changes to JavaScript code can be live reloaded without rebuilding the native app.
- Portability. Reuse code across iOS, Android, and other platforms.
React Native is developed and supported by many companies and individual core contributors. Find out more in our ecosystem overview.
Contents
- Requirements
- Building your first React Native app
- Documentation
- Upgrading
- How to Contribute
- Code of Conduct
- License
📋 Requirements
React Native apps may target iOS 10.0 and Android 4.1 (API 16) or newer. You may use Windows, macOS, or Linux as your development operating system, though building and running iOS apps is limited to macOS. Tools like Expo can be used to work around this.
🎉 Building your first React Native app
Follow the Getting Started guide. The recommended way to install React Native depends on your project. Here you can find short guides for the most common scenarios:
📖 Documentation
The full documentation for React Native can be found on our website.
The React Native documentation discusses components, APIs, and topics that are specific to React Native. For further documentation on the React API that is shared between React Native and React DOM, refer to the React documentation.
The source for the React Native documentation and website is hosted on a separate repo, @facebook/react-native-website.
🚀 Upgrading
Upgrading to new versions of React Native may give you access to more APIs, views, developer tools, and other goodies. See the Upgrading Guide for instructions.
React Native releases are discussed in the React Native Community, @react-native-community/react-native-releases.
👏 How to Contribute
The main purpose of this repository is to continue evolving React Native core. We want to make contributing to this project as easy and transparent as possible, and we are grateful to the community for contributing bug fixes and improvements. Read below to learn how you can take part in improving React Native.
Code of Conduct
Facebook has adopted a Code of Conduct that we expect project participants to adhere to. Please read the full text so that you can understand what actions will and will not be tolerated.
Contributing Guide
Read our Contributing Guide to learn about our development process, how to propose bugfixes and improvements, and how to build and test your changes to React Native.
Open Source Roadmap
You can learn more about our vision for React Native in the Roadmap.
Good First Issues
We have a list of good first issues that contain bugs which have a relatively limited scope. This is a great place to get started, gain experience, and get familiar with our contribution process.
Discussions
Larger discussions and proposals are discussed in @react-native-community/discussions-and-proposals.
📄 License
React Native is MIT licensed, as found in the LICENSE file.
React Native documentation is Creative Commons licensed, as found in the LICENSE-docs file.