From 66d688fb68df0418654290ab6c55b96404e6c743 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Tue, 27 Aug 2024 23:13:33 +0200
Subject: [PATCH] OpenFileGDB writer: fix writing a Int32 field with value
 -21121

---
 autotest/ogr/ogr_openfilegdb_write.py         | 19 +++++++++++++++++++
 .../openfilegdb/ogropenfilegdblayer_write.cpp |  1 +
 2 files changed, 20 insertions(+)

diff --git a/autotest/ogr/ogr_openfilegdb_write.py b/autotest/ogr/ogr_openfilegdb_write.py
index 08ef72a8221f..5b0410b395ff 100755
--- a/autotest/ogr/ogr_openfilegdb_write.py
+++ b/autotest/ogr/ogr_openfilegdb_write.py
@@ -4565,3 +4565,22 @@ def test_ogr_openfilegdb_repair_corrupted_header(tmp_vsimem):
         ds = ogr.Open(filename)
     assert gdal.GetLastErrorMsg() == ""
     assert ds.GetLayerCount() == 1
+
+
+###############################################################################
+# Test writing special value OGRUnsetMarker = -21121 in a int32 field
+
+
+def test_ogr_openfilegdb_write_OGRUnsetMarker(tmp_vsimem):
+
+    filename = str(tmp_vsimem / "out.gdb")
+    with ogr.GetDriverByName("OpenFileGDB").CreateDataSource(filename) as ds:
+        lyr = ds.CreateLayer("test", geom_type=ogr.wkbNone)
+        lyr.CreateField(ogr.FieldDefn("i32", ogr.OFTInteger))
+        f = ogr.Feature(lyr.GetLayerDefn())
+        f["i32"] = -21121
+        lyr.CreateFeature(f)
+    with ogr.Open(filename) as ds:
+        lyr = ds.GetLayer(0)
+        f = lyr.GetNextFeature()
+        assert f["i32"] == -21121
diff --git a/ogr/ogrsf_frmts/openfilegdb/ogropenfilegdblayer_write.cpp b/ogr/ogrsf_frmts/openfilegdb/ogropenfilegdblayer_write.cpp
index c832ae36631b..eb64f204b835 100644
--- a/ogr/ogrsf_frmts/openfilegdb/ogropenfilegdblayer_write.cpp
+++ b/ogr/ogrsf_frmts/openfilegdb/ogropenfilegdblayer_write.cpp
@@ -2263,6 +2263,7 @@ bool OGROpenFileGDBLayer::PrepareFileGDBFeature(OGRFeature *poFeature,
             }
             continue;
         }
+        memset(&fields[idxFileGDB], 0, sizeof(OGRField));
         switch (m_poLyrTable->GetField(idxFileGDB)->GetType())
         {
             case FGFT_UNDEFINED: