VoiceOver: fix the link crash, and take language, links, text styles and rotors from scope settings

[AllenChen-Xingan]

VoiceOver support in the editor, rebuilt on scope settings. I use TextMate full time with VoiceOver, mostly on documents that mix Chinese and English; these are the changes that make that work, written so that they fit TextMate’s design rather than special-casing my languages.

Revision 2 (force-pushed): fixes a crash that also affects the release build, moves the work into a buffer hook next to the symbols, and takes the review comments on the first version. Details at the end.

The idea: accessibility follows scopes

Where the spelling checker looks is already a scope setting (spellChecking), and what goes into the symbol list is too (showInSymbolList). The editor’s accessibility information now works the same way. TextMate itself hard-codes no language, file type or scope; it only reads these settings, and bundles provide the defaults next to their existing spell-checking settings:

Setting	Values	Effect
accessibilityLanguage	auto, none (also when unset), or a BCP 47 tag	Which voice VoiceOver reads the text in. auto identifies the language with the NaturalLanguage framework, one run per script within each sentence
accessibilityLink (+ accessibilityLinkTitleTransformation, accessibilityLinkURLTransformation)	bool + symbolTransformation syntax	What is a link, what VoiceOver reads as its title, and the URL it opens
accessibilityTextStyle	any of bold italic underline strikethrough	What the text means, independent of whether the theme draws it that way
accessibilityRotor (+ …Transformation, …Extent, …Order)	heading, link, list, table, image, bold, italic, … for one of VoiceOver’s own rotors, or a name (optionally localized) for a custom one	A VoiceOver rotor (VO-U) listing the matching text

With no settings, behaviour is unchanged: nothing is tagged, exactly as VoiceOver experiences TextMate today.

Everything lives in one buffer hook, ng::accessibility_t, built like symbols_t: settings are read once per scope and cached (cleared when bundles change), links and rotor items sit in indexed maps that shift with edits, and edits and parsing only widen a range that the next accessibility query brings up to date. Nothing is computed while no assistive client asks.

Commits

1. Install the app’s localization as en.lproj. With only English.lproj, TextMate reports AXPreferredLanguage = "English" where every other app reports "en". VoiceOver cannot resolve it and falls back to a voice without Chinese phonemes, so any Chinese announcement made while TextMate is frontmost is silent. The existing sources are installed as en.lproj with CFBundleDevelopmentRegion to match; no second localization.
2. Use the documented name of the marked-misspelled attribute (NSAccessibilityMarkedMisspelledTextAttribute).
3. Compile symbol transformations once and reuse them. symbols.cc’s private transform type becomes ng::symbol_transform_t, so the settings above can use it.
4. Expose links through NSAccessibilityElement. Fixes a crash in the release build: VoiceOver on macOS 27 asks every element for AXFocused, AXEnabled, … through AXUIElementCopyMultipleAttributeValues, which reaches the legacy accessibilityAttributeValue: without consulting the attribute list, and OakAccessibleLink raised NSAccessibilityException there. AppKit would catch it, but the NSExceptionHandler delegate aborts first, so opening a Markdown file with one bare URL while VoiceOver runs crashes 2.3.0-undead on launch. The element is rebuilt on the current protocol; frames and the activation point are computed from the range on demand; pressing opens the URL (the action was a TODO).
5. Add grammar-defined VoiceOver rotors. Introduces the buffer hook.
6. Take the accessibility language of text from its scope. The text view tagged the whole buffer with the spelling language under "AXNaturalLanguageText" (2013, before NSAccessibilityLanguageTextAttribute existed in 10.13); nothing recognises that key, so VoiceOver never knew the language of any text. Now ns::identify_languages splits a line into sentences and script runs and asks NLLanguageRecognizer; the user’s preferred languages settle what is uncertain (a few characters of Chinese are as often taken for Traditional as for Simplified). Results are cached per line. Unit tests in Frameworks/ns/tests/t_language.mm.
7. Take accessibility links from scope settings. Links were limited to the hard-coded markup.underline.link and always had a nil URL. Behaviour change: plain URLs need accessibilityLink on markup.underline.link — see the Text bundle PR.
8. Report text styles to accessibility from scope settings.
9. Do not abort on NSAccessibilityException. Generalises the existing NSMenu exemption in OakAssert.mm: AppKit’s accessibility entry points catch these themselves.

Companion bundle PRs (the defaults)

• Add accessibility settings for text text.tmbundle#2 — language auto for text, none for links and raw; URLs are links; styles for markup.bold/italic/underline/strikethrough
• Read comments and strings in their own language source.tmbundle#3 — auto for comments and strings only
• Add VoiceOver rotors and link targets for Markdown markdown.tmbundle#4 — rotors (VoiceOver’s own Headings/Links/Lists/Images/Bold/Italic plus custom ones), titles and URLs for [text](url)
• Add VoiceOver rotors for tables and strikethrough GitHub-Markdown.tmbundle#5 — table and strikethrough rotors and style

The embedded Text and Source pins would need bumping once those are merged.

Testing (macOS 27.0, VoiceOver on)

• Accessibility-API probes on a Markdown file mixing Chinese, English and a Python block: links (role, title, URL, AXEnabled, activation point, hit test, AXPress), styles, per-sentence languages (The coaching session went well. 客户说他很满意。Next steps are clear. → en / zh-Hans / en; identifiers untagged, comments tagged), 14 rotors; an empty document; replacing the whole text through AXValue and checking links, rotors and languages follow.
• The untouched release build crashes on the same file under the same probes; this branch does not.
• Performance, interleaved with a Release build of main on a 6,120-line Markdown file, medians of three rounds: AXAttributedStringForRange per line 0.33 ms → 0.40 ms (first read of a line identifies its language; later reads hit the cache); edit then read 3.9–4.1 ms → 2.6–2.8 ms (the old link index rescanned the whole document after every parse); rotors plus children 0.06 ms → 0.13 ms (14 rotors instead of one).
• ns_tests pass; buffer_test has the same 3 spell-checking failures as main on this machine.

Found along the way, not addressed here: when ~/Library/Application Support/TextMate/Bundles is created after the first launch, the cached BundlesIndex.binary never picks it up; deleting the cache fixes it.

The patches are contributed under the repository’s license (GPL-3.0-or-later).

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[dayglojesus]

Thanks @AllenChen-Xingan — this is a substantial and well-argued piece of work, and Revision 2 is a clear step up: the buffer hook with dirty-range updates, transforms compiled once per scope, the link rebuilt on NSAccessibilityElement, and the ns_tests. The AXUIElementCopyMultipleAttributeValues crash is a genuine bug in the release build and I'm glad it surfaced.

I've kicked off CI (first contributions need a manual approval) — results will land on the PR. I'll do a full pass later this week; one item below needs to change before this can merge, the rest are asks and notes.

Blocking: link press needs a URL scheme allowlist.
accessibilityPerformPress opens whatever accessibilityURL holds, and updateAccessibilityChildren only requires URL.scheme to be non-nil. The Markdown grammar's inline-link pattern accepts the URL as (<?)(.*?)(>?) with no scheme constraint, and the title and URL come from two independent transformations — so a document can announce "Read the setup guide" and open file:///…/Terminal.app, x-apple.systempreferences:…, or any third-party handler (vscode://, shortcuts://run-shortcut?…, …) on VO-Space. Before this PR the press action was a no-op; this is the first path in OakTextView where document content selects a system action with one keystroke, and it's built for exactly the users who can't inspect the target first.

Precedent is already in the tree: AboutWindowController.mm:247 refuses file before calling openURL:. Please allow http, https and mailto (and route txmt: through handleTxMtURL: the way OakHTMLOutputView does, if you want it), and treat anything else as a nil URL — the current no-op. That keeps the feature intact for every legitimate link and closes the door on the rest.

Ask: a test for accessibility_t.
t_language.mm covers identification, but the hook is where the logic lives: the dirty-range widening in update_items, links and rotor items surviving edits before and after them, and bundles_did_change forcing a rebuild. buffer_test already has the harness — a t_accessibility.cc driving a buffer_t with a couple of scope settings would give us real coverage of the incremental path.

Notes, non-blocking

• OakAssert.mm: fine by me. After this PR the only remaining NSAccessibilityException thrower is SearchField.mm:7, so the exemption still guards a live path, and matching on the exact name keeps it narrow.
• languages_for_line hands NaturalLanguage the whole line. On a minified one-line file with auto in strings and comments (the Source bundle default), that's one very large pass per edit to that line. A per-line byte cap above which auto is skipped would be cheap insurance.
• The en.lproj rename is consistent within the app bundle (checked). The QuickLook generator and the Dialog plug-ins still install English.lproj — separate bundles, so no mixing, but worth a follow-up for consistency.
• Sequencing: this needs Add accessibility settings for text text.tmbundle#2 to land with it, or bare-URL links disappear for VoiceOver users in between. I'll take the four bundle PRs together with this one and bump the embedded pins after.

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