Fix ANY ARRAY bug (#90)

Author: ryannedolan

hoptimator-util/src/main/java/com/linkedin/hoptimator/util/DataTypeUtils.java

@@ -39,8 +39,7 @@ public static RelDataType flatten(RelDataType dataType, RelDataTypeFactory typeF
 
   private static void flattenInto(RelDataTypeFactory typeFactory, RelDataType dataType,
       RelDataTypeFactory.Builder builder, List<String> path) {
-    if (dataType.getComponentType() != null && (dataType.getComponentType().isStruct()
-        || dataType.getComponentType().getComponentType() != null)) {
+    if (dataType.getComponentType() != null && dataType.getComponentType().isStruct()) {
       // demote complex arrays to just `ANY ARRAY`
       builder.add(path.stream().collect(Collectors.joining("$")), typeFactory.createArrayType(
           typeFactory.createSqlType(SqlTypeName.ANY), -1));

hoptimator-util/src/test/java/com/linkedin/hoptimator/util/TestDataTypeUtils.java

@@ -63,18 +63,20 @@ public void flattenNestedArrays() {
     RelDataTypeFactory.Builder builder3 = new RelDataTypeFactory.Builder(typeFactory);
     builder3.add("FOO", typeFactory.createArrayType(builder1.build(), -1));
     builder3.add("BAR", typeFactory.createArrayType(builder2.build(), -1));
+    builder3.add("CAR", typeFactory.createArrayType(
+        typeFactory.createSqlType(SqlTypeName.FLOAT), -1));
     RelDataType rowType = builder3.build();
-    Assertions.assertEquals(2, rowType.getFieldList().size());
+    Assertions.assertEquals(3, rowType.getFieldList().size());
     RelDataType flattenedType = DataTypeUtils.flatten(rowType, typeFactory);
-    Assertions.assertEquals(2, flattenedType.getFieldList().size());
+    Assertions.assertEquals(3, flattenedType.getFieldList().size());
     List<String> flattenedNames = flattenedType.getFieldList().stream().map(x -> x.getName())
         .collect(Collectors.toList());
-    Assertions.assertIterableEquals(Arrays.asList(new String[]{"FOO", "BAR"}),
+    Assertions.assertIterableEquals(Arrays.asList(new String[]{"FOO", "BAR", "CAR"}),
         flattenedNames);
     String flattenedConnector = new ScriptImplementor.ConnectorImplementor("T1",
         flattenedType, Collections.emptyMap()).sql();
     Assertions.assertEquals("CREATE TABLE IF NOT EXISTS `T1` (`FOO` ANY ARRAY, "
-        + "`BAR` ANY ARRAY) WITH ();", flattenedConnector,
+        + "`BAR` ANY ARRAY, `CAR` FLOAT ARRAY) WITH ();", flattenedConnector,
         "Flattened connector should have simplified arrays");
   }
 }