From ee877536704c17e7e50951f615802eb866dc6973 Mon Sep 17 00:00:00 2001
From: Huite Bootsma <huitebootsma@gmail.com>
Date: Fri, 6 Sep 2024 17:28:42 +0200
Subject: [PATCH] Only replace the fill_value in the returned connectivity if
 it's different from the internal FILL_VALUE

---
 xugrid/ugrid/ugridbase.py | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/xugrid/ugrid/ugridbase.py b/xugrid/ugrid/ugridbase.py
index c72e0700..77c940f8 100644
--- a/xugrid/ugrid/ugridbase.py
+++ b/xugrid/ugrid/ugridbase.py
@@ -485,7 +485,8 @@ def _prepare_connectivity(
 
     def _set_fillvalue(self, connectivity: IntArray) -> IntArray:
         c = connectivity.copy()
-        c[c == FILL_VALUE] = self.fill_value
+        if self.fill_value != FILL_VALUE:
+            c[c == FILL_VALUE] = self.fill_value
         return c
 
     def _precheck(self, multi_index):