From 57bba484d8ba0ce68222dc0fea1aaf5ee73aedc0 Mon Sep 17 00:00:00 2001
From: Tony Qu <tonyqus@gmail.com>
Date: Thu, 27 Jul 2023 19:56:08 +0800
Subject: [PATCH] tolerate duplicate media key, fix #1121

---
 openxml4Net/OPC/PackageRelationshipCollection.cs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/openxml4Net/OPC/PackageRelationshipCollection.cs b/openxml4Net/OPC/PackageRelationshipCollection.cs
index 417e44ba6..654b9119c 100644
--- a/openxml4Net/OPC/PackageRelationshipCollection.cs
+++ b/openxml4Net/OPC/PackageRelationshipCollection.cs
@@ -244,7 +244,8 @@ public PackageRelationship AddRelationship(Uri targetUri,
                     sourcePart, targetUri, targetMode, relationshipType, id);
             relationshipsByID[rel.Id] = rel;
             relationshipsByType[rel.RelationshipType] = rel;
-            if (targetMode == TargetMode.Internal)
+            if (targetMode == TargetMode.Internal
+                && !internalRelationshipsByTargetName.ContainsKey(targetUri.OriginalString))
             {
                 internalRelationshipsByTargetName.Add(targetUri.OriginalString, rel);
             }