## The basics
- [x] I [validated my changes](https://developers.google.com/blockly/guides/contribute/core#making_and_verifying_a_change)
## The details
### Resolves
Fixes part of #8207
Fixes part of #3370
### Proposed Changes
This introduces initial broad ARIA integration in order to enable at least basic screen reader support when using keyboard navigation.
Largely this involves introducing ARIA roles and labels in a bunch of places, sometimes done in a way to override normal built-in behaviors of the accessibility node tree in order to get a richer first-class output for Blockly (such as for blocks and workspaces).
### Reason for Changes
ARIA is the fundamental basis for configuring how focusable nodes in Blockly are represented to the user when using a screen reader. As such, all focusable nodes requires labels and roles in order to correctly communicate their contexts.
The specific approach taken in this PR is to simply add labels and roles to all nodes where obvious with some extra work done for `WorkspaceSvg` and `BlockSvg` in order to represent blocks as a tree (since that seems to be the best fitting ARIA role per those available: https://developer.mozilla.org/en-US/docs/Web/Accessibility/ARIA/Reference/Roles). The custom work specifically for blocks includes:
- Overriding the role description to be 'block' rather than 'tree item' (which is the default).
- Overriding the position, level, and number of sibling counts since those are normally determined based on the DOM tree and blocks are not laid out in the tree the same way they are visually or logically (so these computations were incorrect). This is also the reason for a bunch of extra computation logic being introduced.
One note on some of the labels being nonsensical (e.g. 'DoNotOverride?'): this was done intentionally to try and ensure _all_ focusable nodes (that can be focused) have labels, even when the specifics of what that label should be aren't yet clear. More components had these temporary labels until testing revealed how exactly they would behave from a screen reader perspective (at which point their roles and labels were updated as needed). The temporary labels act as an indicator when navigating through the UI, and some of the nodes can't easily be reached (for reasons) and thus may never actually need a label. More work is needed in understanding both what components need labels and what those labels should be, but that will be done beyond this PR.
### Test Coverage
No tests are added to this as it's experimental and not a final implementation.
The keyboard navigation tests are failing due to a visibility expansion of `connectionCandidate` in `BlockDragStrategy`. There's no way to avoid this breakage, unfortunately. Instead, this PR will be merged and then https://github.com/google/blockly-keyboard-experimentation/pull/684 will be finalized and merged to fix it. There's some additional work that will happen both in that branch and in a later PR in core Blockly to integrate the two experimentation branches as part of #9283 so that CI passes correctly for both branches.
### Documentation
No documentation is needed at this time.
### Additional Information
This work is experimental and is meant to serve two purposes:
- Provide a foundation for testing and iterating the core screen reader experience in Blockly.
- Provide a reference point for designing a long-term solution that accounts for all requirements collected during user testing.
This code should never be merged into `develop` as it stands. Instead, it will be redesigned with maintainability, testing, and correctness in mind at a future date (see https://github.com/google/blockly-keyboard-experimentation/discussions/673).
* feat!: Make bubbles, comments, and icons focusable
* feat!: Make ISelectable and ICopyable focusable.
* feat: Consolidate selection calls.
Now everything is based on focus with selection only being used as a
proxy.
* feat: Invert responsibility for setSelected().
Now setSelected() is only for quasi-external use.
* feat: Push up shadow check to getters.
Needed new common-level helper.
* chore: Lint fixes.
* feat!: Allow IFocusableNode to disable focus.
* chore: post-merge lint fixes
* fix: Fix tests + text bubble focusing.
This fixed then regressed a circular dependency causing the node and
advanced compilation steps to fail. This investigation is ongoing.
* fix: Clean up & fix imports.
This ensures the node and advanced compilation test steps now pass.
* fix: Lint fixes + revert commented out logic.
* chore: Remove unnecessary cast.
Addresses reviewer comment.
* fix: Some issues and a bunch of clean-ups.
This addresses a bunch of review comments, and fixes selecting workspace
comments.
* chore: Lint fix.
* fix: Remove unnecessary shadow consideration.
* chore: Revert import.
* chore: Some doc updates & added a warn statement.
* refactor(events): Use "export ... from" where applicable
* refactor(events): Introduce EventType enum
Introduce an enum for the event .type values. We can't actually
use it as the type of the .type property on Abstract events,
because we want to allow developers to add their own custom
event types inheriting from this type, but at least this way we
can be reasonably sure that all of our own event subclasses have
distinct .type values—plus consistent use of enum syntax
(EventType.TYPE_NAME) is probably good for readability overall.
Put it in a separate module from the rest of events/utils.ts
because it would be helpful if event utils could use
event instanceof SomeEventType
for type narrowing but but at the moment most events are in
modules that depend on events/utils.ts for their .type
constant, and although circular ESM dependencies should work
in principle there are various restrictions and this
particular circularity causes issues at the moment.
A few of the event classes also depend on utils.ts for fire()
or other functions, which will be harder to deal with, but at
least this commit is win in terms of reducing the complexity
of our dependencies, making most of the Abstract event subclass
module dependent on type.ts, which has no imports, rather than
on utils.ts which has multiple imports.
* chore(deps): Add pretter-plugin-organize-imports
* chore: Remove insignificant blank lines in import sections
Since prettier-plugin-organize-imports sorts imports within
sections separated by blank lines, but preserves the section
divisions, remove any blank lines that are not dividing imports
into meaningful sections.
Do not remove blank lines separating side-effect-only imports
from main imports.
* chore: Remove unneded eslint-disable directives
* chore: Organise imports
* feat: add ability to click fields in flyouts
* feat: control if icons are clickable in flyouts
* fix: make default icons not clickable in flyout
* fix: use booleans like a real programmer
* fix(build): Restore erroneously-deleted filter function
This was deleted in PR #7406 as it was mainly being used to
filter core/ vs. test/mocha/ deps into separate deps files -
but it turns out also to be used for filtering error
messages too. Oops.
* refactor(tests): Migrate advanced compilation test to ES Modules
* refactor(build): Migrate main.js to TypeScript
This turns out to be pretty straight forward, even if it would
cause crashing if one actually tried to import this module
instead of just feeding it to Closure Compiler.
* chore(build): Remove goog.declareModuleId calls
Replace goog.declareModuleId calls with a comment recording the
former module ID for posterity (or at least until we decide
how to reformat the renamings file.
* chore(tests): Delete closure/goog/*
For the moment we still need something to serve as base.js for
the benefit of closure-make-deps, so we keep a vestigial
base.js around, containing only the @provideGoog declaration.
* refactor(build): Remove vestigial base.js
By changing slightly the command line arguments to
closure-make-deps and closure-calculate-chunks the need to have
any base.js is eliminated.
* chore: Typo fix for PR #7415
