From f3adb736c06f17f446f696b9c208fb5532ffcbc1 Mon Sep 17 00:00:00 2001
From: Artem Kolosov <artem@ironsoftware.com>
Date: Thu, 2 Jun 2022 11:43:25 +0700
Subject: [PATCH] Upstream fix: stop Mutable section from setting
 MutableProperty with null Value.

It was messing up getting a Size property of a Mutable Section, as it reads the MutableProperty's Value and tries to get it's length, throwing exception.
---
 main/HPSF/MutableSection.cs | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/main/HPSF/MutableSection.cs b/main/HPSF/MutableSection.cs
index 6f7407fa7..aed706511 100644
--- a/main/HPSF/MutableSection.cs
+++ b/main/HPSF/MutableSection.cs
@@ -230,7 +230,10 @@ public void SetProperty(Property p)
         {
             long id = p.ID;
             RemoveProperty(id);
-            preprops.Add(p);
+            if (p.Value != null)
+            {
+                preprops.Add(p);
+            }
             dirty = true;
         }