From b8135129cbc0146fffae3b18c8c895217009d4e2 Mon Sep 17 00:00:00 2001
From: romain v <rvergnory@lucca.fr>
Date: Fri, 2 Apr 2021 16:05:40 +0200
Subject: [PATCH] fix null token handling

in document creation
---
 src/UglyToad.PdfPig/Writer/WriterUtil.cs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/UglyToad.PdfPig/Writer/WriterUtil.cs b/src/UglyToad.PdfPig/Writer/WriterUtil.cs
index 1320cc23..ef13d209 100644
--- a/src/UglyToad.PdfPig/Writer/WriterUtil.cs
+++ b/src/UglyToad.PdfPig/Writer/WriterUtil.cs
@@ -127,6 +127,11 @@
                         // referencesFromDocument.Add(referenceToken.Data, newReferenceToken);
                         // 
                         var tokenObject = DirectObjectFinder.Get<IToken>(referenceToken.Data, tokenScanner);
+                        if (tokenObject is null) //NullToken allowed
+                        {
+                            return null;
+                        }
+
                         Debug.Assert(!(tokenObject is IndirectReferenceToken));
                         var result = CopyToken(writer, tokenObject, tokenScanner, referencesFromDocument, callstack);