Merge pull request #2687 from ClickHouse/client_fix_variant_array

fix reading Array(Varian(String, Int32)) and similar when array has no common component class

Author: chernser

client-v2/src/main/java/com/clickhouse/client/api/data_formats/internal/BinaryStreamReader.java

@@ -624,7 +624,7 @@ public ArrayValue readArray(ClickHouseColumn column) throws IOException {
 
     public ArrayValue readArrayItem(ClickHouseColumn itemTypeColumn, int len) throws IOException {
         ArrayValue array;
-        if (itemTypeColumn.isNullable()) {
+        if (itemTypeColumn.isNullable() || itemTypeColumn.getDataType() == ClickHouseDataType.Variant) {
             array = new ArrayValue(Object.class, len);
             for (int i = 0; i < len; i++) {
                 array.set(i, readValue(itemTypeColumn));

client-v2/src/test/java/com/clickhouse/client/datatypes/DataTypeTests.java

@@ -348,6 +348,18 @@ public void testVariantWithArrays() throws Exception {
                         "[[a, b], [c, d]]",
                         "[[e, f], [j, h]]",
                 });
+
+        testVariantWith("arrays", new String[]{"field Array(Variant(String, Int32))"},
+                new Object[]{
+                        new Object[]{1, 2},
+                        new Object[]{"a", 3},
+                        new Object[]{3, "d"}
+                },
+                new String[]{
+                        "[1, 2]",
+                        "[a, 3]",
+                        "[3, d]",
+                });
     }
 
     @Test(groups = {"integration"})