Throw UnsupportedOperationException in Result.map(…) for SQL variant …

…columns

Indicate that sql_variant is not yet supported.

[resolves #122]

src/main/java/io/r2dbc/mssql/MssqlRow.java

@@ -21,6 +21,7 @@
 import io.r2dbc.mssql.codec.Codecs;
 import io.r2dbc.mssql.message.token.Column;
 import io.r2dbc.mssql.message.token.RowToken;
+import io.r2dbc.mssql.message.type.SqlServerType;
 import io.r2dbc.mssql.util.Assert;
 import io.r2dbc.spi.Row;
 import reactor.util.annotation.Nullable;
@@ -112,6 +113,10 @@ private <T> T doGet(Column column, Class<T> type) {
             return null;
         }
 
+        if (column.getType().getServerType() == SqlServerType.SQL_VARIANT) {
+            throw new UnsupportedOperationException("sql_variant columns not supported. See https://github.com/r2dbc/r2dbc-mssql/issues/67.");
+        }
+
         columnData.markReaderIndex();
 
         try {

src/test/java/io/r2dbc/mssql/SqlVariantIntegrationTests.java

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package io.r2dbc.mssql;
+
+import io.r2dbc.mssql.util.IntegrationTestSupport;
+import org.junit.jupiter.api.Test;
+import reactor.test.StepVerifier;
+
+/**
+ * Integration tests for SQL Variant showing that {@code sql_variant} is not supported.
+ *
+ * @author Mark Paluch
+ */
+class SqlVariantIntegrationTests extends IntegrationTestSupport {
+
+    @Test
+    void shouldExecuteBatch() {
+
+        connection.createStatement(" SELECT SERVERPROPERTY('Edition')").execute()
+            .flatMap(mssqlResult -> mssqlResult.map((row, rowMetadata) -> row.get(0)))
+            .as(StepVerifier::create)
+            .verifyError(UnsupportedOperationException.class);
+    }
+}