From 98f6c6564a4ba76938e7537eba14945e432fd6f7 Mon Sep 17 00:00:00 2001
From: LIM0000 <hihi19982015@hotmail.com>
Date: Wed, 18 May 2022 13:39:58 +0930
Subject: [PATCH] Fix #8012 by adding validation before setting value to field
 that object does not have

---
 src/main/java/org/jabref/gui/entryeditor/SourceTab.java | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/main/java/org/jabref/gui/entryeditor/SourceTab.java b/src/main/java/org/jabref/gui/entryeditor/SourceTab.java
index d1773f9563f..b9b534d30eb 100644
--- a/src/main/java/org/jabref/gui/entryeditor/SourceTab.java
+++ b/src/main/java/org/jabref/gui/entryeditor/SourceTab.java
@@ -306,7 +306,9 @@ private void storeSource(BibEntry outOfFocusEntry, String text) {
                     new FieldWriter(fieldWriterPreferences).write(fieldName, newValue);
 
                     compound.addEdit(new UndoableFieldChange(outOfFocusEntry, fieldName, oldValue, newValue));
-                    outOfFocusEntry.setField(fieldName, newValue);
+                    if (outOfFocusEntry.getField(fieldName).isPresent()) {
+                        outOfFocusEntry.setField(fieldName, newValue);
+                    }
                 }
             }