fdeaa7692b
## The basics - [x] I [validated my changes](https://developers.google.com/blockly/guides/contribute/core#making_and_verifying_a_change) ## The details ### Resolves Fixes #8940 Fixes #8954 Fixes #8955 ### Proposed Changes This updates `LineCursor` to use `FocusManager` rather than selection (principally) as the source of truth. ### Reason for Changes Ensuring that keyboard navigation works correctly with eventual screen reader support requires ensuring that ever navigated component is focused, and this is primarily what `FocusManager` has been designed to do. Since these nodes are already focused, `FocusManager` can be used as the primary source of truth for determining where the user currently has navigated, and where to go next. Previously, `LineCursor` relied on selection for this purpose, but selection is now automatically updated (for blocks) using focus-controlled `focus` and `blur` callbacks. Note that the cursor will still fall back to synchronizing with selection state, though this will be removed once the remaining work to eliminate `MarkerSvg` has concluded (which requires further consideration on the keyboard navigation side viz-a-viz styling and CSS decisions) and once mouse clicks are synchronized with focus management. Note that the changes in this PR are closely tied to https://github.com/google/blockly-keyboard-experimentation/pull/482 as both are necessary in order for the keyboard navigation plugin to correctly work with `FocusManager`. Some other noteworthy changes: - Some special handling exists for flyouts to handle navigating across stacks (per the current cursor design). - `FocusableTreeTraverser` is needed by the keyboard navigation plugin (in https://github.com/google/blockly-keyboard-experimentation/pull/482) so it's now being exported. - `FocusManager` had one bug that's now patched and tested in this PR: it didn't handle the case of the browser completely forcing focus loss. It would continue to maintain active focus even though no tracked elements now hold focus. One such case is the element being deleted, but there are other cases where this can happen (such as with dialog prompts). - `FocusManager` had some issues from #8909 wherein it would overeagerly call tree focus callbacks and slightly mismanage the passive node. Since tests haven't yet been added for these lifecycle callbacks, these cases weren't originally caught (per #8910). - `FocusManager` was updated to move the tracked manager into a static function so that it can be replaced in tests. This was done to facilitate changes to setup_teardown.js to ensure that a unique `FocusManager` exists _per-test_. It's possible for DOM focus state to still bleed across tests, but `FocusManager` largely guarantees eventual consistency. This change prevents a class of focus errors from being possible when running tests. - A number of cursor tests needed to be updated to ensure that a connections are properly rendered (as this is a requirement for focusable nodes, and cursor is now focusing nodes). One test for output connections was changed to use an input connection, instead, since output connections can no longer be navigated to (and aren't rendered, thus are not focusable). It's possible this will need to be changed in the future if we decide to reintroduce support for output connections in cursor, but it seems like a reasonable stopgap. Huge thanks to @rachel-fenichel for helping investigate and providing an alternative for the output connection test. **Current gaps** to be fixed after this PR is merged: - The flyout automatically closes when creating a variable with with keyboard or mouse (I think this is only for the keyboard navigation plugin). I believe this is a regression from previous behavior due to how the navigation plugin is managing state. It would know the flyout should be open and thus ensure it stays open even when things like dialog prompts try to close it with a blur event. However, the new implementation in https://github.com/google/blockly-keyboard-experimentation/pull/482 complicates this since state is now inferred from `FocusManager`, and the flyout _losing_ focus will force it closed. There was a fix introduced in this PR to fix it for keyboard navigation, but fails for clicks because the flyout never receives focus when the create variable button is clicked. It also caused the advanced compilation tests to fail due to a subtle circular dependency from importing `WorkspaceSvg` directly rather than its type. - The flyout, while it stays open, does not automatically update past the first variable being created without closing and reopening it. I'm actually not at all sure why this particular behavior has regressed. ### Test Coverage No new non-`FocusManager` tests have been added. It's certainly possible to add unit tests for the focusable configurations being introduced in this PR, but it may not be highly beneficial. It's largely assumed that the individual implementations should work due to a highly tested FocusManager, and it may be the case that the interactions of the components working together is far more important to verify (that is, the end user flows). The latter is planned to be tackled as part of #8915. Some new `FocusManager` tests were added, but more are still needed and this is tracked as part of #8910. ### Documentation No new documentation should be needed for these changes. ### Additional Information This includes changes that have been pulled from #8875.
Blockly
Google's Blockly is a library that adds a visual code editor to web and mobile apps. The Blockly editor uses interlocking, graphical blocks to represent code concepts like variables, logical expressions, loops, and more. It allows users to apply programming principles without having to worry about syntax or the intimidation of a blinking cursor on the command line. All code is free and open source.
Getting Started with Blockly
Blockly has many resources for learning how to use the library. Start at our Google Developers Site to read the documentation on how to get started, configure Blockly, and integrate it into your application. The developers site also contains links to:
Help us focus our development efforts by telling us what you are doing with Blockly. The questionnaire only takes a few minutes and will help us better support the Blockly community.
Installing Blockly
Blockly is available on npm.
npm install blockly
For more information on installing and using Blockly, see the Getting Started article.
Getting Help
- Report a bug or file a feature request on GitHub
- Ask a question, or search others' questions, on our developer forum. You can also drop by to say hello and show us your prototypes; collectively we have a lot of experience and can offer hints which will save you time. We actively monitor the forums and typically respond to questions within 2 working days.
blockly-samples
We have a number of resources such as example code, demos, and plugins in another repository called blockly-samples. A plugin is a self-contained piece of code that adds functionality to Blockly. Plugins can add fields, define themes, create renderers, and much more. For more information, see the Plugins documentation.
Contributing to Blockly
Want to make Blockly better? We welcome contributions to Blockly in the form of pull requests, bug reports, documentation, answers on the forum, and more! Check out our Contributing Guidelines for more information. You might also want to look for issues tagged "Help Wanted" which are issues we think would be great for external contributors to help with.
Releases
We release by pushing the latest code to the master branch, followed by updating the npm package, our docs, and demo pages. If there are breaking bugs, such as a crash when performing a standard action or a rendering issue that makes Blockly unusable, we will cherry-pick fixes to master between releases to fix them. The releases page has a list of all releases.
We use semantic versioning. Releases that have breaking changes or are otherwise not backwards compatible will have a new major version. Patch versions are reserved for bug-fix patches between scheduled releases.
We now have a beta release on npm. If you'd like to test the upcoming release, or try out a not-yet-released new API, you can use the beta channel with:
npm install blockly@beta
As it is a beta channel, it may be less stable, and the APIs there are subject to change.
Branches
There are two main branches for Blockly.
master - This is the (mostly) stable current release of Blockly.
develop - This is where most of our work happens. Pull requests should always be made against develop. This branch will generally be usable, but may be less stable than the master branch. Once something is in develop we expect it to merge to master in the next release.
other branches: - Larger changes may have their own branches until they are good enough for people to try out. These will be developed separately until we think they are almost ready for release. These branches typically get merged into develop immediately after a release to allow extra time for testing.
New APIs
Once a new API is merged into master it is considered beta until the following release. We generally try to avoid changing an API after it has been merged to master, but sometimes we need to make changes after seeing how an API is used. If an API has been around for at least two releases we'll do our best to avoid breaking it.
Unreleased APIs may change radically. Anything that is in develop but not master is subject to change without warning.
Issues and Milestones
We typically triage all bugs within 1 week, which includes adding any appropriate labels and assigning it to a milestone. Please keep in mind, we are a small team so even feature requests that everyone agrees on may not be prioritized.
Good to Know
- Cross-browser Testing Platform and Open Source <3 Provided by Sauce Labs
- We test browsers using BrowserStack