From 0f16e82430e716b9b1e72f699d9d4d164c22abfa Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Sun, 25 Aug 2024 22:27:26 +0200
Subject: [PATCH] netCDF: do not override GDALPamDataset::TrySaveXML() to allow
 proper mixing of classic and multidim PAM metadata

---
 autotest/gdrivers/netcdf_multidim.py |  9 ++++++
 frmts/netcdf/netcdfdataset.cpp       | 43 ++--------------------------
 frmts/netcdf/netcdfdataset.h         |  2 --
 3 files changed, 11 insertions(+), 43 deletions(-)

diff --git a/autotest/gdrivers/netcdf_multidim.py b/autotest/gdrivers/netcdf_multidim.py
index f8a993f1dfca..c6134d376c07 100755
--- a/autotest/gdrivers/netcdf_multidim.py
+++ b/autotest/gdrivers/netcdf_multidim.py
@@ -4005,9 +4005,17 @@ def test2():
         rg_subset = rg.SubsetDimensionFromSelection("/x=440750")
         rg_subset.OpenMDArray("Band1").GetStatistics(False, force=True)
 
+    def test3():
+        ds = gdal.Open(filename)
+        ds.SetMetadataItem("foo", "bar")
+
     def reopen():
 
+        ds = gdal.Open(filename)
+        assert ds.GetMetadataItem("foo") == "bar"
+
         aux_xml = open(filename + ".aux.xml", "rb").read().decode("UTF-8")
+        assert '<MDI key="foo">bar</MDI>' in aux_xml
         assert (
             '<DerivedDataset name="AsClassicDataset(1,0) view of Sliced view of /Band1 ([0:10,...])">'
             in aux_xml
@@ -4053,6 +4061,7 @@ def reopen():
 
     test()
     test2()
+    test3()
     reopen()
 
 
diff --git a/frmts/netcdf/netcdfdataset.cpp b/frmts/netcdf/netcdfdataset.cpp
index e2b2eddcfb94..87d52223e980 100644
--- a/frmts/netcdf/netcdfdataset.cpp
+++ b/frmts/netcdf/netcdfdataset.cpp
@@ -3033,6 +3033,7 @@ CPLErr netCDFDataset::SetMetadataItem(const char *pszName, const char *pszValue,
             strchr(osName.c_str(), '#') != nullptr)
         {
             // do nothing
+            return CE_None;
         }
         else
         {
@@ -3065,6 +3066,7 @@ CPLErr netCDFDataset::SetMetadata(char **papszMD, const char *pszDomain)
                 SetMetadataItem(pszName, pszValue);
             CPLFree(pszName);
         }
+        return CE_None;
     }
     return GDALPamDataset::SetMetadata(papszMD, pszDomain);
 }
@@ -3081,47 +3083,6 @@ const OGRSpatialReference *netCDFDataset::GetSpatialRef() const
     return GDALPamDataset::GetSpatialRef();
 }
 
-/************************************************************************/
-/*                           SerializeToXML()                           */
-/************************************************************************/
-
-CPLXMLNode *netCDFDataset::SerializeToXML(const char *pszUnused)
-
-{
-    // Overridden from GDALPamDataset to add only band histogram
-    // and statistics. See bug #4244.
-
-    if (psPam == nullptr)
-        return nullptr;
-
-    // Setup root node and attributes.
-    CPLXMLNode *psDSTree = CPLCreateXMLNode(nullptr, CXT_Element, "PAMDataset");
-
-    // Process bands.
-    for (int iBand = 0; iBand < GetRasterCount(); iBand++)
-    {
-        netCDFRasterBand *poBand =
-            static_cast<netCDFRasterBand *>(GetRasterBand(iBand + 1));
-
-        if (poBand == nullptr || !(poBand->GetMOFlags() & GMO_PAM_CLASS))
-            continue;
-
-        CPLXMLNode *psBandTree = poBand->SerializeToXML(pszUnused);
-
-        if (psBandTree != nullptr)
-            CPLAddXMLChild(psDSTree, psBandTree);
-    }
-
-    // We don't want to return anything if we had no metadata to attach.
-    if (psDSTree->psChild == nullptr)
-    {
-        CPLDestroyXMLNode(psDSTree);
-        psDSTree = nullptr;
-    }
-
-    return psDSTree;
-}
-
 /************************************************************************/
 /*                           FetchCopyParam()                            */
 /************************************************************************/
diff --git a/frmts/netcdf/netcdfdataset.h b/frmts/netcdf/netcdfdataset.h
index fe869dd2e431..536dddae7184 100644
--- a/frmts/netcdf/netcdfdataset.h
+++ b/frmts/netcdf/netcdfdataset.h
@@ -544,8 +544,6 @@ class netCDFDataset final : public GDALPamDataset
     void SetSpatialRefNoUpdate(const OGRSpatialReference *);
 
   protected:
-    CPLXMLNode *SerializeToXML(const char *pszVRTPath) override;
-
     OGRLayer *ICreateLayer(const char *pszName,
                            const OGRGeomFieldDefn *poGeomFieldDefn,
                            CSLConstList papszOptions) override;