fix(ui): prevent shiki template-call OOM on backtick JS

Neutralize the catastrophic TextMate template-call lookahead when loading JS/TS grammars in the markdown Shiki worker, and terminate hung highlight requests after 5s so unbounded Oniguruma WASM matching cannot OOM the renderer (openchamber/openchamber#2587). Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>
2026-08-04 11:35:42 +00:00
parent f47110c66f
commit 2b67be0a07
6 changed files with 197 additions and 11 deletions
@@ -0,0 +1,45 @@
+/**
+ * Neutralize the JavaScript/TypeScript TextMate `template-call` rule.
+ *
+ * Upstream grammars use a triple-nested `{()[]}` lookahead to detect tagged
+ * templates with type arguments (`foo<T>\`...\``). On the Oniguruma WASM engine
+ * shipped with Shiki — which does not expose `setRetryLimit` / match-stack
+ * limits — that pattern can enter exponential backtracking on ordinary
+ * backtick template literals, grow the WASM heap without bound, and OOM the
+ * renderer (openchamber/openchamber#2587).
+ *
+ * Clearing `template-call` is safe: the plain `#template` rule still highlights
+ * backticks and simple tagged templates. Only the rare `ident<TypeArgs>\`...\``
+ * form loses its specialized type-argument coloring and falls through to
+ * normal tokenization.
+ */
+
+type GrammarRepository = Record<string, { patterns?: unknown[] } | undefined>;
+
+export type TemplateCallGrammar = {
+  name?: string;
+  repository?: GrammarRepository;
+};
+
+const TEMPLATE_CALL_KEY = 'template-call';
+
+export const hasCatastrophicTemplateCall = (grammar: TemplateCallGrammar): boolean => {
+  const patterns = grammar.repository?.[TEMPLATE_CALL_KEY]?.patterns;
+  return Array.isArray(patterns) && patterns.length > 0;
+};
+
+export const sanitizeTemplateCallGrammar = <T extends TemplateCallGrammar>(grammar: T): T => {
+  if (!hasCatastrophicTemplateCall(grammar)) return grammar;
+
+  const repository = { ...grammar.repository };
+  repository[TEMPLATE_CALL_KEY] = { patterns: [] };
+  return { ...grammar, repository };
+};
+
+/** Language ids whose bundled grammars ship the catastrophic `template-call` rule. */
+export const TEMPLATE_CALL_LANGUAGE_IDS = ['javascript', 'typescript', 'jsx', 'tsx'] as const;
+
+export type TemplateCallLanguageId = (typeof TEMPLATE_CALL_LANGUAGE_IDS)[number];
+
+export const isTemplateCallLanguageId = (lang: string): lang is TemplateCallLanguageId =>
+  (TEMPLATE_CALL_LANGUAGE_IDS as readonly string[]).includes(lang);