From 7b4f88246058ff184d96b5c226d9f7eef7a93512 Mon Sep 17 00:00:00 2001
From: Shivam Gupta <sudhanshudasgupta9@gmail.com>
Date: Sat, 28 Dec 2024 18:56:27 +0000
Subject: [PATCH] mutation issue

Signed-off-by: Shivam Gupta <sudhanshudasgupta9@gmail.com>
---
 gatsby-config.js | 2 +-
 gatsby-node.js   | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/gatsby-config.js b/gatsby-config.js
index c6fab89b8e09..773e33bffba3 100644
--- a/gatsby-config.js
+++ b/gatsby-config.js
@@ -14,7 +14,7 @@ module.exports = {
   flags: {
     FAST_DEV: true,
     PARALLEL_SOURCING: true,
-    // PRESERVE_FILE_DOWNLOAD_CACHE: true,
+    PRESERVE_FILE_DOWNLOAD_CACHE: true,
     DETECT_NODE_MUTATIONS: true,
     PARTIAL_HYDRATION: true
   },
diff --git a/gatsby-node.js b/gatsby-node.js
index c38e2531ceed..9f44ad37dbb9 100644
--- a/gatsby-node.js
+++ b/gatsby-node.js
@@ -905,6 +905,15 @@ exports.onCreateNode = ({ node, actions, getNode }) => {
         onCreateChapterNode({ actions, node, slug });
         return;
       }
+
+      if (node.internal.type === "Mdx") {
+        if (!node.frontmatter.thumbnail) {
+          node.frontmatter.thumbnail = null;
+        }
+        if (!node.frontmatter.darkthumbnail) {
+          node.frontmatter.darkthumbnail = null;
+        }
+      }
     }
   }
 };