From 95d1300adad99e00e54d411dc5c5a5b7b5d37405 Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Tue, 9 Sep 2025 12:21:05 +0200
Subject: [PATCH 1/2] don't overwrite but merge keys for pandoc

---
 src/command/render/pandoc.ts | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/command/render/pandoc.ts b/src/command/render/pandoc.ts
index 91b4371db40..15f939c6eed 100644
--- a/src/command/render/pandoc.ts
+++ b/src/command/render/pandoc.ts
@@ -1147,8 +1147,22 @@ export async function runPandoc(
       if (key === kFieldCategories && projectIsWebsite(options.project)) {
         continue;
       }
-      // perform the override
-      pandocMetadata[key] = engineMetadata[key];
+
+      if (
+        (typeof pandocMetadata[key] === "object" &&
+          typeof engineMetadata[key] === "object") ||
+        (Array.isArray(pandocMetadata[key]) &&
+          Array.isArray(engineMetadata[key]))
+      ) {
+        // Merge objects and arrays instead of replacing
+        pandocMetadata[key] = mergeConfigs(
+          pandocMetadata[key],
+          engineMetadata[key],
+        );
+      } else {
+        // Replace values otherwise
+        pandocMetadata[key] = engineMetadata[key];
+      }
     }
   }
 

From efed3d3b94749bfc00a3e1105e25ad857f8740df Mon Sep 17 00:00:00 2001
From: Julius Krumbiegel <julius.krumbiegel@gmail.com>
Date: Tue, 9 Sep 2025 13:38:16 +0200
Subject: [PATCH 2/2] simplify and fix array bug by calling merge on temp
 objects instead

---
 src/command/render/pandoc.ts | 21 ++++++---------------
 1 file changed, 6 insertions(+), 15 deletions(-)

diff --git a/src/command/render/pandoc.ts b/src/command/render/pandoc.ts
index 15f939c6eed..40a577cfad0 100644
--- a/src/command/render/pandoc.ts
+++ b/src/command/render/pandoc.ts
@@ -1148,21 +1148,12 @@ export async function runPandoc(
         continue;
       }
 
-      if (
-        (typeof pandocMetadata[key] === "object" &&
-          typeof engineMetadata[key] === "object") ||
-        (Array.isArray(pandocMetadata[key]) &&
-          Array.isArray(engineMetadata[key]))
-      ) {
-        // Merge objects and arrays instead of replacing
-        pandocMetadata[key] = mergeConfigs(
-          pandocMetadata[key],
-          engineMetadata[key],
-        );
-      } else {
-        // Replace values otherwise
-        pandocMetadata[key] = engineMetadata[key];
-      }
+      // to handle all possible objects correctly when merging,
+      // we call mergeConfigs on temporary objects so the structure
+      // matches what that function expects
+      const a = { content: pandocMetadata[key] };
+      const b = { content: engineMetadata[key] };
+      pandocMetadata[key] = mergeConfigs(a, b).content;
     }
   }