fix: IDs may conflict

Author: RYGRIT

server/utils/readme.ts

@@ -272,6 +272,10 @@ function withUserContentPrefix(value: string): string {
   return value.startsWith(USER_CONTENT_PREFIX) ? value : `${USER_CONTENT_PREFIX}${value}`
 }
 
+function toUserContentId(value: string): string {
+  return `${USER_CONTENT_PREFIX}${value}`
+}
+
 function toUserContentHash(value: string): string {
   return `#${withUserContentPrefix(value)}`
 }
@@ -446,13 +450,13 @@ export async function renderReadmeHtml(
     const count = usedSlugs.get(slug) ?? 0
     usedSlugs.set(slug, count + 1)
     const uniqueSlug = count === 0 ? slug : `${slug}-${count}`
-    const id = withUserContentPrefix(uniqueSlug)
+    const id = toUserContentId(uniqueSlug)
 
     if (plainText) {
       toc.push({ text: plainText, id, depth })
     }
 
-    return `<h${semanticLevel} id="${id}" data-level="${depth}"><a href="#${uniqueSlug}">${plainText}</a></h${semanticLevel}>\n`
+    return `<h${semanticLevel} id="${id}" data-level="${depth}"><a href="#${id}">${plainText}</a></h${semanticLevel}>\n`
   }
 
   renderer.heading = function ({ tokens, depth }: Tokens.Heading) {

test/unit/server/utils/readme.spec.ts

@@ -642,6 +642,17 @@ describe('Issue #1323 — single-pass rendering correctness', () => {
       expect(ids).toEqual(['user-content-api', 'user-content-api-1', 'user-content-api-2'])
     })
 
+    it('does not collide when heading text already starts with user-content-', async () => {
+      const md = ['# Title', '', '# user-content-title'].join('\n')
+
+      const result = await renderReadmeHtml(md, 'test-pkg')
+
+      const ids = Array.from(result.html.matchAll(/id="(user-content-[^"]+)"/g), m => m[1])
+      expect(ids).toEqual(['user-content-title', 'user-content-user-content-title'])
+      expect(new Set(ids).size).toBe(ids.length)
+      expect(result.toc.map(t => t.id)).toEqual(ids)
+    })
+
     it('heading semantic levels are sequential even when mixing heading types', async () => {
       // h1 (md) → h3, h3 (html) → should be h4 (max = lastSemantic + 1),
       // not jump to h5 or h6 because it was processed in a later pass.