From 83124522f7cf9240107574d4c9183c69454877bf Mon Sep 17 00:00:00 2001
From: Hrithik Saini <49943287+hrithiksaini99@users.noreply.github.com>
Date: Wed, 4 Nov 2026 12:48:35 +0530
Subject: [PATCH 1/2] fix(utils): do not drop trailing hash in heading title
 unless preceded by space

---
 .../src/__tests__/markdownUtils.test.ts       | 56 +++++++++++++++++++
 .../docusaurus-utils/src/markdownUtils.ts     |  3 +-
 2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/packages/docusaurus-utils/src/__tests__/markdownUtils.test.ts b/packages/docusaurus-utils/src/__tests__/markdownUtils.test.ts
index 34648991ba35..a96233b9f134 100644
--- a/packages/docusaurus-utils/src/__tests__/markdownUtils.test.ts
+++ b/packages/docusaurus-utils/src/__tests__/markdownUtils.test.ts
@@ -438,6 +438,62 @@ Lorem Ipsum
     });
   });
 
+  it('parses markdown h1 title ending with # when not preceded by space (e.g. C#)', () => {
+    const markdown = dedent`
+
+          # Learn C#
+
+          Lorem Ipsum
+
+        `;
+    expect(parseMarkdownContentTitle(markdown)).toEqual({
+      content: markdown,
+      contentTitle: 'Learn C#',
+    });
+  });
+
+  it('parses markdown h1 title ending with # and trailing ATX closing marker', () => {
+    const markdown = dedent`
+
+          # Learn C# #
+
+          Lorem Ipsum
+
+        `;
+    expect(parseMarkdownContentTitle(markdown)).toEqual({
+      content: markdown,
+      contentTitle: 'Learn C#',
+    });
+  });
+
+  it('parses markdown h1 title ending with # and custom anchor-id', () => {
+    const markdown = dedent`
+
+          # Learn C# {#learn-c-sharp}
+
+          Lorem Ipsum
+
+        `;
+    expect(parseMarkdownContentTitle(markdown)).toEqual({
+      content: markdown,
+      contentTitle: 'Learn C#',
+    });
+  });
+
+  it('parses markdown h1 title ending with attached # (e.g. foo#)', () => {
+    const markdown = dedent`
+
+          # foo#
+
+          Lorem Ipsum
+
+        `;
+    expect(parseMarkdownContentTitle(markdown)).toEqual({
+      content: markdown,
+      contentTitle: 'foo#',
+    });
+  });
+
   it('parses markdown h1 title at the top followed by h2 title', () => {
     const markdown = dedent`
 
diff --git a/packages/docusaurus-utils/src/markdownUtils.ts b/packages/docusaurus-utils/src/markdownUtils.ts
index 76f824f33ebd..ff85ad42543d 100644
--- a/packages/docusaurus-utils/src/markdownUtils.ts
+++ b/packages/docusaurus-utils/src/markdownUtils.ts
@@ -334,7 +334,8 @@ export function parseMarkdownContentTitle(
       contentTitle: toTextContentTitle(
         regularTitleMatch
           .groups!.title!.trim()
-          .replace(/\s*(?:\{#*[\w-]+\}|#+)$/, ''),
+          .replace(/\s*\{#*[\w-]+\}$/, '')
+          .replace(/\s+#+$/, ''),
       ).trim(),
     };
   }

From 89d11401010944d7138facbd7066845826fb75d0 Mon Sep 17 00:00:00 2001
From: Hrithik Saini <49943287+hrithiksaini99@users.noreply.github.com>
Date: Wed, 4 Nov 2026 13:14:30 +0530
Subject: [PATCH 2/2] fix(utils): handle all-hash heading titles when stripping
 closing markers

---
 .../src/__tests__/markdownUtils.test.ts            | 14 ++++++++++++++
 packages/docusaurus-utils/src/markdownUtils.ts     |  2 +-
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/packages/docusaurus-utils/src/__tests__/markdownUtils.test.ts b/packages/docusaurus-utils/src/__tests__/markdownUtils.test.ts
index a96233b9f134..11f5b2942745 100644
--- a/packages/docusaurus-utils/src/__tests__/markdownUtils.test.ts
+++ b/packages/docusaurus-utils/src/__tests__/markdownUtils.test.ts
@@ -494,6 +494,20 @@ Lorem Ipsum
     });
   });
 
+  it('parses empty markdown h1 title with closing # marker only', () => {
+    const markdown = dedent`
+
+          # #
+
+          Lorem Ipsum
+
+        `;
+    expect(parseMarkdownContentTitle(markdown)).toEqual({
+      content: markdown,
+      contentTitle: '',
+    });
+  });
+
   it('parses markdown h1 title at the top followed by h2 title', () => {
     const markdown = dedent`
 
diff --git a/packages/docusaurus-utils/src/markdownUtils.ts b/packages/docusaurus-utils/src/markdownUtils.ts
index ff85ad42543d..980e4d1aee58 100644
--- a/packages/docusaurus-utils/src/markdownUtils.ts
+++ b/packages/docusaurus-utils/src/markdownUtils.ts
@@ -335,7 +335,7 @@ export function parseMarkdownContentTitle(
         regularTitleMatch
           .groups!.title!.trim()
           .replace(/\s*\{#*[\w-]+\}$/, '')
-          .replace(/\s+#+$/, ''),
+          .replace(/(?:^|\s+)#+$/, ''),
       ).trim(),
     };
   }