[fix](Variant) check enable light_schema_change when create table with variant type

fe/fe-core/src/main/java/org/apache/doris/datasource/InternalCatalog.java

@@ -2507,6 +2507,16 @@ private boolean createOlapTable(Database db, CreateTableStmt stmt) throws UserEx
         // use light schema change optimization
         olapTable.setEnableLightSchemaChange(enableLightSchemaChange);
 
+        // check if light schema change is disabled, variant type rely on light schema change
+        if (!enableLightSchemaChange) {
+            for (Column column : baseSchema) {
+                if (column.getType().isVariantType()) {
+                    throw new DdlException("Variant type rely on light schema change, "
+                            + " please use light_schema_change = true.");
+                }
+            }
+        }
+
         boolean disableAutoCompaction = false;
         try {
             disableAutoCompaction = PropertyAnalyzer.analyzeDisableAutoCompaction(properties);

regression-test/suites/variant_p0/load.groovy

@@ -446,6 +446,22 @@ suite("regression_test_variant", "p0"){
             exception("Invalid type for variant column: 36")
         }
 
+         test {
+            sql """
+            create table var(
+                `key` int,
+                `content` variant
+            )
+            DUPLICATE KEY(`key`)
+            distributed by hash(`key`) buckets 8
+            properties(
+              "replication_allocation" = "tag.location.default: 1",
+              "light_schema_change" = "false"
+            );
+            """
+            exception("errCode = 2, detailMessage = Variant type rely on light schema change")
+        }
+
     } finally {
         // reset flags
     }