fix: strip frontmatter before heading includes (#5246)

__tests__/unit/node/markdownToVue.test.ts

@@ -67,6 +67,63 @@ describe('node/markdownToVue', () => {
     })
   })
 
+  test('selects included heading sections after frontmatter', async () => {
+    root = await mkdtemp(path.join(tmpdir(), 'vitepress-include-'))
+
+    const file = path.join(root, 'index.md')
+    const source = path.join(root, 'source.md')
+    await writeFile(
+      source,
+      [
+        '---',
+        'description: Source description',
+        '---',
+        '# Intro',
+        '',
+        'intro text',
+        '',
+        '## Shared',
+        '',
+        'shared before target',
+        '',
+        '## Target',
+        '',
+        'target text',
+        '',
+        '### Child',
+        '',
+        'child text',
+        '',
+        '## Shared',
+        '',
+        'shared after target',
+        ''
+      ].join('\n')
+    )
+    const src = '<!--@include: ./source.md#target-->'
+    await writeFile(file, src)
+
+    const siteConfig = await resolveConfig(root, 'build', 'production')
+    const render = await createMarkdownToVueRenderFn(
+      siteConfig.srcDir,
+      { cache: false },
+      '/',
+      false,
+      false,
+      siteConfig
+    )
+
+    const result = await render(src, file, 'public')
+
+    expect(result.vueSrc).toContain('<p>target text</p>')
+    expect(result.vueSrc).toContain('<h3 id="child"')
+    expect(result.vueSrc).toContain('<p>child text</p>')
+    expect(result.vueSrc).not.toContain('Source description')
+    expect(result.vueSrc).not.toContain('intro text')
+    expect(result.vueSrc).not.toContain('shared before target')
+    expect(result.vueSrc).not.toContain('shared after target')
+  })
+
   test('applies rewrites with mismatched Windows drive letter case', async () => {
     root = await mkdtemp(path.join(tmpdir(), 'vitepress-rewrite-'))
 

src/node/utils/processIncludes.ts

@@ -41,12 +41,18 @@ export function processIncludes(
     if (region) {
       const [regionName] = region
       const lines = content.split(/\r?\n/)
+      let selectedLines = lines
       let { start, end } = findRegion(lines, regionName.slice(1)) ?? {}
 
       if (start === undefined) {
         // region not found, it might be a header
+        const headerContent =
+          path.extname(includePath) === '.md'
+            ? matter(content).content
+            : content
+        const headerLines = headerContent.split(/\r?\n/)
         const tokens = md
-          .parse(content, {
+          .parse(headerContent, {
             path: includePath,
             relativePath: slash(path.relative(srcDir, includePath)),
             cleanUrls
@@ -57,6 +63,7 @@ export function processIncludes(
         )
         const token = tokens[idx]
         if (token) {
+          selectedLines = headerLines
           start = token.map![1]
           const level = parseInt(token.tag.slice(1))
           for (let i = idx + 1; i < tokens.length; i++) {
@@ -68,7 +75,7 @@ export function processIncludes(
         }
       }
 
-      content = lines.slice(start, end).join('\n')
+      content = selectedLines.slice(start, end).join('\n')
     }
 
     if (range) {