From 00023c24b66f7813cacb81e0ee2412636da04e00 Mon Sep 17 00:00:00 2001
From: Joshua Chen <sidachen2003@gmail.com>
Date: Wed, 18 Jan 2023 13:19:07 -0500
Subject: [PATCH] fix(core): avoid hash collision when generating chunk names
 (#8538)

---
 .../src/server/__tests__/routes.test.ts       | 34 +++++++++++++++++++
 packages/docusaurus/src/server/routes.ts      |  8 ++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/packages/docusaurus/src/server/__tests__/routes.test.ts b/packages/docusaurus/src/server/__tests__/routes.test.ts
index 3f8197c990..f302b3c450 100644
--- a/packages/docusaurus/src/server/__tests__/routes.test.ts
+++ b/packages/docusaurus/src/server/__tests__/routes.test.ts
@@ -56,6 +56,40 @@ describe('genChunkName', () => {
     });
     expect(genChunkName('d', undefined, undefined, true)).toBe('8277e091');
   });
+
+  // https://github.com/facebook/docusaurus/issues/8536
+  it('avoids hash collisions', () => {
+    expect(
+      genChunkName(
+        '@site/blog/2022-11-18-bye-medium/index.mdx?truncated=true',
+        'content',
+        'blog',
+        false,
+      ),
+    ).not.toBe(
+      genChunkName(
+        '@site/blog/2019-10-05-react-nfc/index.mdx?truncated=true',
+        'content',
+        'blog',
+        false,
+      ),
+    );
+    expect(
+      genChunkName(
+        '@site/blog/2022-11-18-bye-medium/index.mdx?truncated=true',
+        'content',
+        'blog',
+        true,
+      ),
+    ).not.toBe(
+      genChunkName(
+        '@site/blog/2019-10-05-react-nfc/index.mdx?truncated=true',
+        'content',
+        'blog',
+        true,
+      ),
+    );
+  });
 });
 
 describe('handleDuplicateRoutes', () => {
diff --git a/packages/docusaurus/src/server/routes.ts b/packages/docusaurus/src/server/routes.ts
index 6b731b7586..6a63fa71ca 100644
--- a/packages/docusaurus/src/server/routes.ts
+++ b/packages/docusaurus/src/server/routes.ts
@@ -51,6 +51,7 @@ function indent(str: string) {
 }
 
 const chunkNameCache = new Map<string, string>();
+const chunkNameCount = new Map<string, number>();
 
 /**
  * Generates a unique chunk name that can be used in the chunk registry.
@@ -79,10 +80,15 @@ export function genChunkName(
         const shortHash = simpleHash(modulePath, 3);
         str = `${preferredName}${shortHash}`;
       }
-      const name = str === '/' ? 'index' : docuHash(str);
+      const name = docuHash(str);
       chunkName = prefix ? `${prefix}---${name}` : name;
     }
+    const seenCount = (chunkNameCount.get(chunkName) ?? 0) + 1;
+    if (seenCount > 1) {
+      chunkName += seenCount.toString(36);
+    }
     chunkNameCache.set(modulePath, chunkName);
+    chunkNameCount.set(chunkName, seenCount);
   }
   return chunkName;
 }