From 3fe683abc2393a8961c30d98243ffe8beff67bd4 Mon Sep 17 00:00:00 2001
From: "Kamat, Trivikram" <16024985+trivikr@users.noreply.github.com>
Date: Sat, 4 Apr 2026 21:03:23 -0700
Subject: [PATCH 1/2] fix(ui): normalize README heading fragments to lowercase
 slugs

- Decode and slugify in-page README anchors before prefixing
- Keep already prefixed `user-content` fragments unchanged
- Add coverage for mixed-case heading links
---
 server/utils/readme.ts                | 19 +++++++++++++++++--
 test/unit/server/utils/readme.spec.ts |  7 +++++++
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/server/utils/readme.ts b/server/utils/readme.ts
index b5befe67b7..1c03a4e4be 100644
--- a/server/utils/readme.ts
+++ b/server/utils/readme.ts
@@ -298,6 +298,14 @@ function toUserContentHash(value: string): string {
   return `#${withUserContentPrefix(value)}`
 }
 
+function decodeHashFragment(value: string): string {
+  try {
+    return decodeURIComponent(value)
+  } catch {
+    return value
+  }
+}
+
 function normalizePreservedAnchorAttrs(attrs: string): string {
   const cleanedAttrs = attrs
     .replace(/\s+href\s*=\s*("[^"]*"|'[^']*'|[^\s>]+)/gi, '')
@@ -333,8 +341,15 @@ function resolveUrl(url: string, packageName: string, repoInfo?: RepositoryInfo)
   if (!url) return url
   if (url.startsWith('#')) {
     // Prefix anchor links to match heading IDs (avoids collision with page IDs)
-    // Idempotent: don't double-prefix if already prefixed
-    return toUserContentHash(url.slice(1))
+    // Normalize markdown-style heading fragments to the same slug format used
+    // for generated README heading IDs, but leave already-prefixed values as-is.
+    const fragment = url.slice(1)
+    if (fragment.startsWith(USER_CONTENT_PREFIX)) {
+      return `#${fragment}`
+    }
+
+    const normalizedFragment = slugify(decodeHashFragment(fragment))
+    return toUserContentHash(normalizedFragment || fragment)
   }
   // Absolute paths (e.g. /package/foo from a previous npmjs redirect) are already resolved
   if (url.startsWith('/')) return url
diff --git a/test/unit/server/utils/readme.spec.ts b/test/unit/server/utils/readme.spec.ts
index 3269f01850..5d85902158 100644
--- a/test/unit/server/utils/readme.spec.ts
+++ b/test/unit/server/utils/readme.spec.ts
@@ -293,6 +293,13 @@ describe('Markdown File URL Resolution', () => {
 
       expect(result.html).toContain('href="#user-content-installation"')
     })
+
+    it('normalizes mixed-case heading fragments to lowercase slugs', async () => {
+      const markdown = `[Associations section](#Associations)`
+      const result = await renderReadmeHtml(markdown, 'test-pkg')
+
+      expect(result.html).toContain('href="#user-content-associations"')
+    })
   })
 
   describe('different git providers', () => {

From 2ec90faa36dfd6e68a88ab50e99794172fe6453a Mon Sep 17 00:00:00 2001
From: "Kamat, Trivikram" <16024985+trivikr@users.noreply.github.com>
Date: Sat, 4 Apr 2026 23:34:31 -0700
Subject: [PATCH 2/2] fix: handle empty hash fragments while resolving URLs

---
 server/utils/readme.ts | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/server/utils/readme.ts b/server/utils/readme.ts
index 1c03a4e4be..a97e620ebd 100644
--- a/server/utils/readme.ts
+++ b/server/utils/readme.ts
@@ -344,6 +344,9 @@ function resolveUrl(url: string, packageName: string, repoInfo?: RepositoryInfo)
     // Normalize markdown-style heading fragments to the same slug format used
     // for generated README heading IDs, but leave already-prefixed values as-is.
     const fragment = url.slice(1)
+    if (!fragment) {
+      return '#'
+    }
     if (fragment.startsWith(USER_CONTENT_PREFIX)) {
       return `#${fragment}`
     }