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fix: wait for stylesheets to be loaded before adopting them - #834
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On Firefox, a constructed CSSStyleSheet stays "still-loading" until its replace() promise settles, and reading its cssRules throws an InvalidAccessError. Browser extensions that proxy the adoptedStyleSheets setter (e.g. Dark Reader) read cssRules from the setter, so adopting the sheets right after registering them made initialize() reject and the editor never load. Refs darkreader/darkreader#14329 Co-authored-by: Cursor <cursoragent@cursor.com>
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The font face sheet is built synchronously with insertRule inside the then of its own sheet promise, so it is never still-loading and there is no need to wait for the other sheets before adopting it on the document. Co-authored-by: Cursor <cursoragent@cursor.com>
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Problem
Since #825 (
d16f931),registerCsscreates constructed stylesheets with the asyncCSSStyleSheet.replace(), andinjectCss()adopts them right away at the start ofinitialize().On Firefox, a constructed sheet stays "still-loading" until its
replace()promise settles, and reading itscssRulesin the meantime throwsInvalidAccessError: Can't access rules of still-loading style sheet. Browser extensions that proxy theadoptedStyleSheetssetter readcssRuleson each adopted sheet — Dark Reader does (isDRAdoptedSheetOverride→onAdoptedSheetsChange, upstream issue darkreader/darkreader#14329). The setter throws,initialize()rejects.Fix
src/css.ts: keep everyreplace()promise insheetPromises;whenSheetsLoaded()isPromise.allSettledover them.injectCss()becomesasyncand awaitswhenSheetsLoaded()before settingroot.adoptedStyleSheets.@font-facesheet adopted ondocumentis deferred the same way.src/services.ts:initialize()nowawaitsinjectCss(container)(it was already async, so no API change for callers).Validation
Repro loading the editor with Dark Reader's
adoptedStyleSheetsproxy injected:InvalidAccessErroron adoption,initialize()rejects.