From d75fea1cab3a6ee0fc1fdcaae5e83ca2ebcd0de6 Mon Sep 17 00:00:00 2001
From: Even Rouault <even.rouault@spatialys.com>
Date: Mon, 27 Nov 2023 23:07:59 +0100
Subject: [PATCH] ExecuteSQL(): add a warning if the dialect name isn't
 recognized (fixes #8843)

---
 gcore/gdaldataset.cpp                         | 30 +++++++++++++++++++
 .../gpkg/ogrgeopackagedatasource.cpp          |  7 +++--
 .../sqlite/ogrsqlitedatasource.cpp            | 10 ++++---
 3 files changed, 40 insertions(+), 7 deletions(-)

diff --git a/gcore/gdaldataset.cpp b/gcore/gdaldataset.cpp
index 1b622ed06d03..f359c4b9b3b6 100644
--- a/gcore/gdaldataset.cpp
+++ b/gcore/gdaldataset.cpp
@@ -6478,6 +6478,36 @@ GDALDataset::ExecuteSQL(const char *pszStatement, OGRGeometry *poSpatialFilter,
 #endif
     }
 
+    if (pszDialect != nullptr && !EQUAL(pszDialect, "") &&
+        !EQUAL(pszDialect, "OGRSQL"))
+    {
+        std::string osDialectList = "'OGRSQL'";
+#ifdef SQLITE_ENABLED
+        osDialectList += ", 'SQLITE'";
+#endif
+        const char *pszDialects =
+            GetMetadataItem(GDAL_DMD_SUPPORTED_SQL_DIALECTS);
+        if (pszDialects)
+        {
+            const CPLStringList aosTokens(
+                CSLTokenizeString2(pszDialects, " ", 0));
+            for (int i = 0; i < aosTokens.size(); ++i)
+            {
+                if (!EQUAL(aosTokens[i], "OGRSQL") &&
+                    !EQUAL(aosTokens[i], "SQLITE"))
+                {
+                    osDialectList += ", '";
+                    osDialectList += aosTokens[i];
+                    osDialectList += "'";
+                }
+            }
+        }
+        CPLError(CE_Warning, CPLE_NotSupported,
+                 "Dialect '%s' is unsupported. Only supported dialects are %s. "
+                 "Defaulting to OGRSQL",
+                 pszDialect, osDialectList.c_str());
+    }
+
     /* -------------------------------------------------------------------- */
     /*      Handle CREATE INDEX statements specially.                       */
     /* -------------------------------------------------------------------- */
diff --git a/ogr/ogrsf_frmts/gpkg/ogrgeopackagedatasource.cpp b/ogr/ogrsf_frmts/gpkg/ogrgeopackagedatasource.cpp
index 0a9c9f3ea6fa..34868ed6b6ad 100644
--- a/ogr/ogrsf_frmts/gpkg/ogrgeopackagedatasource.cpp
+++ b/ogr/ogrsf_frmts/gpkg/ogrgeopackagedatasource.cpp
@@ -7310,11 +7310,12 @@ OGRLayer *GDALGeoPackageDataset::ExecuteSQL(const char *pszSQLCommand,
         return nullptr;
     }
 
-    if (pszDialect != nullptr && EQUAL(pszDialect, "OGRSQL"))
-        return GDALDataset::ExecuteSQL(osSQLCommand, poSpatialFilter,
-                                       pszDialect);
     else if (pszDialect != nullptr && EQUAL(pszDialect, "INDIRECT_SQLITE"))
         return GDALDataset::ExecuteSQL(osSQLCommand, poSpatialFilter, "SQLITE");
+    else if (pszDialect != nullptr && !EQUAL(pszDialect, "NATIVE") &&
+             !EQUAL(pszDialect, "SQLITE"))
+        return GDALDataset::ExecuteSQL(osSQLCommand, poSpatialFilter,
+                                       pszDialect);
 
 #if SQLITE_VERSION_NUMBER < 3007017
     // Emulate PRAGMA application_id
diff --git a/ogr/ogrsf_frmts/sqlite/ogrsqlitedatasource.cpp b/ogr/ogrsf_frmts/sqlite/ogrsqlitedatasource.cpp
index e845a9b6b8e5..f6d7252a44e9 100644
--- a/ogr/ogrsf_frmts/sqlite/ogrsqlitedatasource.cpp
+++ b/ogr/ogrsf_frmts/sqlite/ogrsqlitedatasource.cpp
@@ -3206,12 +3206,14 @@ OGRLayer *OGRSQLiteDataSource::ExecuteSQL(const char *pszSQLCommand,
         }
     }
 
-    if (pszDialect != nullptr && EQUAL(pszDialect, "OGRSQL"))
-        return GDALDataset::ExecuteSQL(pszSQLCommand, poSpatialFilter,
-                                       pszDialect);
-    else if (pszDialect != nullptr && EQUAL(pszDialect, "INDIRECT_SQLITE"))
+    if (pszDialect != nullptr && EQUAL(pszDialect, "INDIRECT_SQLITE"))
         return GDALDataset::ExecuteSQL(pszSQLCommand, poSpatialFilter,
                                        "SQLITE");
+    else if (pszDialect != nullptr && !EQUAL(pszDialect, "NATIVE") &&
+             !EQUAL(pszDialect, "SQLITE"))
+
+        return GDALDataset::ExecuteSQL(pszSQLCommand, poSpatialFilter,
+                                       pszDialect);
 
     /* -------------------------------------------------------------------- */
     /*      Special case DELLAYER: command.                                 */