DGN (v7) driver: emit explicit error when attempting to open a DGNv8 …

autotest/ogr/ogr_dgn.py

@@ -30,7 +30,7 @@
 import ogrtest
 import pytest
 
-from osgeo import ogr
+from osgeo import gdal, ogr
 
 pytestmark = pytest.mark.require_driver("DGN")
 
@@ -293,3 +293,23 @@ def test_ogr_dgn_online_1():
     wkt = "LINESTRING (82.9999500717185 23.2084166997284,83.0007450788903 23.2084495986816,83.00081490524 23.2068095339824,82.9999503769036 23.2067737968078)"
 
     ogrtest.check_feature_geometry(feat, wkt)
+
+
+###############################################################################
+# Test opening a (not supported by this driver) DGNv8 file
+
+
+def test_ogr_dgn_open_dgnv8_not_supported():
+
+    dgnv8_drv = gdal.GetDriverByName("DGNv8")
+    if dgnv8_drv:
+        dgnv8_drv.Deregister()
+    try:
+        with pytest.raises(
+            Exception,
+            match="recognized as a DGNv8 dataset, but the DGNv8 driver is not available in this GDAL build",
+        ):
+            ogr.Open("data/dgnv8/test_dgnv8.dgn")
+    finally:
+        if dgnv8_drv:
+            dgnv8_drv.Register()

gcore/gdal.h

@@ -1013,6 +1013,12 @@ GDALDatasetH CPL_DLL CPL_STDCALL GDALOpenShared(const char *, GDALAccess)
 #define GDAL_OF_BLOCK_ACCESS_MASK 0x300
 #endif
 
+#ifndef DOXYGEN_SKIP
+/** Set by GDALOpenEx() to indicate to Identify() method that they are called
+ * from it */
+#define GDAL_OF_FROM_GDALOPEN 0x400
+#endif
+
 GDALDatasetH CPL_DLL CPL_STDCALL GDALOpenEx(
     const char *pszFilename, unsigned int nOpenFlags,
     const char *const *papszAllowedDrivers, const char *const *papszOpenOptions,

gcore/gdaldataset.cpp

@@ -3614,6 +3614,7 @@ GDALDatasetH CPL_STDCALL GDALOpenEx(const char *pszFilename,
     }
 
     oOpenInfo.papszOpenOptions = papszOpenOptionsCleaned;
+    oOpenInfo.nOpenFlags |= GDAL_OF_FROM_GDALOPEN;
 
 #ifdef OGRAPISPY_ENABLED
     const bool bUpdate = (nOpenFlags & GDAL_OF_UPDATE) != 0;

gcore/gdaldriver.cpp

@@ -122,7 +122,7 @@ GDALDataset *GDALDriver::Open(GDALOpenInfo *poOpenInfo, bool bSetOpenOptions)
 
     if (poDS)
     {
-        poDS->nOpenFlags = poOpenInfo->nOpenFlags;
+        poDS->nOpenFlags = poOpenInfo->nOpenFlags & ~GDAL_OF_FROM_GDALOPEN;
 
         if (strlen(poDS->GetDescription()) == 0)
             poDS->SetDescription(poOpenInfo->pszFilename);

ogr/ogrsf_frmts/dgn/ogrdgndriver.cpp

@@ -36,8 +36,32 @@
 static int OGRDGNDriverIdentify(GDALOpenInfo *poOpenInfo)
 
 {
-    return poOpenInfo->fpL != nullptr && poOpenInfo->nHeaderBytes >= 512 &&
-           DGNTestOpen(poOpenInfo->pabyHeader, poOpenInfo->nHeaderBytes);
+    if (poOpenInfo->fpL != nullptr && poOpenInfo->nHeaderBytes >= 512 &&
+        DGNTestOpen(poOpenInfo->pabyHeader, poOpenInfo->nHeaderBytes))
+    {
+        return TRUE;
+    }
+
+    // Is this is a DGNv8 file ? If so, and if the DGNV8 driver is not
+    // available, and we are called from GDALError(), emit an explicit
+    // error.
+    VSIStatBuf sStat;
+    if ((poOpenInfo->nOpenFlags & GDAL_OF_FROM_GDALOPEN) != 0 &&
+        poOpenInfo->papszAllowedDrivers == nullptr &&
+        poOpenInfo->fpL != nullptr && poOpenInfo->nHeaderBytes >= 512 &&
+        memcmp(poOpenInfo->pabyHeader, "\xD0\xCF\x11\xE0\xA1\xB1\x1A\xE1", 8) ==
+            0 &&
+        EQUAL(CPLGetExtension(poOpenInfo->pszFilename), "DGN") &&
+        VSIStat(poOpenInfo->pszFilename, &sStat) == 0 &&
+        GDALGetDriverByName("DGNV8") == nullptr)
+    {
+        CPLError(CE_Failure, CPLE_AppDefined,
+                 "`%s' recognized as a DGNv8 dataset, but the DGNv8 driver is "
+                 "not available in this GDAL build. Consult "
+                 "https://gdal.org/drivers/vector/dgnv8.html",
+                 poOpenInfo->pszFilename);
+    }
+    return FALSE;
 }
 
 /************************************************************************/