HIVE-28262:Single column use MultiDelimitSerDe parse column error

[LaughingVzr]

What changes were proposed in this pull request?

modify LazyStruct#findIndexes function and LazyStruct#parseMultiDelimit function, change fields.length Conditional judgment：

public void parseMultiDelimit(byte[] rawRow, byte[] fieldDelimit) {
     - if (fields.length > 1 && delimitIndexes[i - 1] != -1) {
     + if (delimitIndexes[i - 1] != -1) {
  }

 private int[] findIndexes(byte[] array, byte[] target) {
    - if (fields.length <= 1) {
    + if (fields.length < 1) {
   ...
    - for (int i = 1; i < indexes.length; i++) {
    + for (int i = 1; i <= indexes.length; i++) {
    ...
    }
    return indexes;
  }

I add an test for this fix:

@Test
    public void testParseMultiDelimit() throws Throwable {
        try {
            // single field named id
            List<String> structFieldNames = new ArrayList<>();
            structFieldNames.add("id");
            // field type is string
            List<TypeInfo> fieldTypes = new ArrayList<>();
            PrimitiveTypeInfo primitiveTypeInfo = new PrimitiveTypeInfo();
            primitiveTypeInfo.setTypeName("string");
            fieldTypes.add(primitiveTypeInfo);

            // separators + escapeChar => "|�����"
            byte[] separators = new byte[]{124, 2, 3, 4, 5, 6, 7, 8};

            // sequence =>"\N"
            Text sequence = new Text();
            sequence.set(new byte[]{92, 78});

            // create lazy object inspector parameters
            LazyObjectInspectorParameters lazyObjectInspectorParameters = new LazyObjectInspectorParametersImpl(false, (byte) '0',
                    false, null, separators, sequence);
            // create a lazy struct inspector
            ObjectInspector lazyStructInspector = LazyFactory.createLazyStructInspector(structFieldNames, fieldTypes, lazyObjectInspectorParameters);
            LazyStruct lazyStruct = (LazyStruct) LazyFactory.createLazyObject(lazyStructInspector);

            // origin row data
            String rowData = "1|@|";
            // row field delimiter
            String fieldDelimiter = "|@|";

            // parse row use multi delimit
            lazyStruct.parseMultiDelimit(rowData.getBytes(StandardCharsets.UTF_8),
                    fieldDelimiter.getBytes(StandardCharsets.UTF_8));

            // check the first field and second field start position index
            // before fix result: 0,1
            // after fix result: 0,2
            Assert.assertArrayEquals(new int[]{0, 2}, lazyStruct.startPosition);
        } catch (Throwable e) {
            e.printStackTrace();
            throw e;
        }
    }

Why are the changes needed?

If a table only have one column field with multidelimit，query this column data is error data.
When I use this data to do other operation(e.g cast use UDFToLong function),get result is NULL.

Does this PR introduce any user-facing change?

No

Is the change a dependency upgrade?

No

How was this patch tested?

test class: serde/src/test/org/apache/hadoop/hive/serde2/lazy/TestLazyStruct.java
test function: org.apache.hadoop.hive.serde2.lazy.TestLazyStruct#testParseMultiDelimit
test command: mvn test -Dtest=TestLazyStruct --pl serde

[sonarcloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
No data about Coverage
No data about Duplication

See analysis details on SonarCloud

[zhangbutao]

Hi, @LaughingVzr Thanks for you contribution. Failed tests seemed to be related your change, Please take a look: http://ci.hive.apache.org/blue/organizations/jenkins/hive-precommit/detail/PR-5252/7/tests