frontend/src/features/editor/VisualMarkdownEditor.spec.ts

@@ -56,6 +56,12 @@ describe('VisualMarkdownEditor formatting toolbars', () => {
     const config = editor.action(ctx => ctx.get(codeBlockConfig.key))
     const matching = config.languages.filter(item => item.alias.includes('python'))
     expect(matching).toHaveLength(1)
+    for (const name of ['Java', 'Go', 'Rust']) {
+      const language = config.languages.find(item => item.name === name)
+      expect(language, `${name} remains available`).toBeDefined()
+      const support = await language!.load()
+      expect(support.language.parser.parse('class Example {}').length).toBe(16)
+    }
     const cm = new CodeMirror({ doc: 'print("Hello")', extensions: [...config.extensions, await matching[0]!.load()] })
     try {
       const string = [...cm.dom.querySelectorAll<HTMLElement>('.shiki-token')].find(el => el.textContent?.includes('Hello'))

frontend/src/features/editor/VisualMarkdownEditor.vue

@@ -179,7 +179,7 @@ onMounted(async () => {
   // Replace both AFTER feature configuration to avoid default grammar collisions.
   crepe.editor.config(ctx => ctx.update(codeBlockConfig.key, config => ({
     ...config,
-    languages: shikiLanguages(themeStore.resolvedCodeBlockTheme),
+    languages: shikiLanguages(themeStore.resolvedCodeBlockTheme, config.languages),
     extensions: [basicSetup, keymap.of([indentWithTab]), shikiEditorTheme(themeStore.resolvedCodeBlockTheme)],
   })))
   crepe.editor.use(fontSizeMarkdownPlugin)

frontend/src/features/editor/shikiCodeMirror.spec.ts

@@ -1,6 +1,7 @@
 // @vitest-environment happy-dom
 import { afterEach, expect, it } from 'vitest'
 import { Compartment } from '@codemirror/state'
+import { LanguageDescription } from '@codemirror/language'
 import { EditorView } from '@codemirror/view'
 import { shikiLanguage, shikiLanguages } from './shikiCodeMirror'
 import { getCodeTokenizer } from '@/utils/markdown'
@@ -41,3 +42,16 @@ it('offers fenced-code aliases and retains the LaTeX selector', () => {
   expect(languages.find(item => item.name === 'Python')?.alias).toContain('py')
   expect(languages.find(item => item.name === 'LaTeX')?.alias).toContain('latex')
 })
+
+it('preserves original loaders and metadata while replacing supported languages', async () => {
+  const originalPython = LanguageDescription.of({ name: 'Python', alias: ['py', 'custom-python'], extensions: ['py'], filename: /^SConstruct$/, load: () => shikiLanguage('text', 'github-light') })
+  const originalRust = LanguageDescription.of({ name: 'Rust', alias: ['rs'], extensions: ['rs'], load: () => shikiLanguage('text', 'github-light') })
+  const languages = shikiLanguages('github-dark', [originalPython, originalRust])
+  expect(languages.find(item => item.name === 'Rust')).toBe(originalRust)
+  const python = languages.find(item => item.name === 'Python')!
+  expect(languages.filter(item => item.alias.includes('python'))).toHaveLength(1)
+  expect(python.alias).toContain('custom-python')
+  expect(python.extensions).toEqual(['py'])
+  expect(python.filename).toBe(originalPython.filename)
+  expect(await python.load()).not.toBe(await originalPython.load())
+})

frontend/src/features/editor/shikiCodeMirror.ts

@@ -39,8 +39,8 @@ export async function shikiLanguage(language: string, theme: CodeTheme): Promise
   return new LanguageSupport(parser, highlights)
 }
 
-export function shikiLanguages(theme: CodeTheme): LanguageDescription[] {
-  return [
+export function shikiLanguages(theme: CodeTheme, originalLanguages: readonly LanguageDescription[] = []): LanguageDescription[] {
+  const overrides = [
     { name: 'C', alias: ['c'] },
     { name: 'C++', alias: ['cpp', 'c++'] },
     { name: 'Python', alias: ['python', 'py'] },
@@ -57,6 +57,22 @@ export function shikiLanguages(theme: CodeTheme): LanguageDescription[] {
   ].map(({ name, alias }) => LanguageDescription.of({
     name, alias, load: () => shikiLanguage(alias[0]!, theme),
   }))
+  // Keep Crepe's full registry and lazy loaders for languages without Shiki grammars.
+  const remaining = new Map(overrides.map(language => [language.name.toLowerCase(), language]))
+  const languages = originalLanguages.map(original => {
+    const key = original.name.toLowerCase()
+    const replacement = remaining.get(key)
+    if (!replacement) return original
+    remaining.delete(key)
+    return LanguageDescription.of({
+      name: original.name,
+      alias: [...new Set([...original.alias, ...replacement.alias])],
+      extensions: original.extensions,
+      filename: original.filename,
+      load: () => replacement.load(),
+    })
+  })
+  return [...languages, ...remaining.values()]
 }
 
 export function shikiEditorTheme(theme: CodeTheme) {