[jira] [Updated] (ARROW-15971) [C++/Java] Error when reading inner lists within a struct in empty outer lists from C++/Python in Java

["Arrow User (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/ARROW-15971?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Arrow User updated ARROW-15971:
-------------------------------
    Summary: [C++/Java] Error when reading inner lists within a struct in empty outer lists from C++/Python in Java  (was: Error when reading inner lists within a struct in empty outer lists from C++/Python in Java)

> [C++/Java] Error when reading inner lists within a struct in empty outer lists from C++/Python in Java
> ------------------------------------------------------------------------------------------------------
>
>                 Key: ARROW-15971
>                 URL: https://issues.apache.org/jira/browse/ARROW-15971
>             Project: Apache Arrow
>          Issue Type: Bug
>          Components: C++, Java, Python
>    Affects Versions: 7.0.0
>            Reporter: Arrow User
>            Priority: Major
>              Labels: bug
>
> h2. Description
> When using C++ (or Python) to construct a null or empty outer array of type *array_1: list<item: struct<array_sub_col: list<item: string>>>*, either:
> {noformat}
> -  array_1: null
> -  array_1: []
> {noformat}
> an out of bounds exceptions (see stack trace below) follows when later retrieving the field reader for the inner list (*array_sub_col*) in Java.
> h2. Reproduction
> *Java*: 7.0.0
> *C++*: 4.0.0
> *Python*: 7.0.0
> Creating a stream on C++ of type *array_1: list<item: struct<array_sub_col: list<item: string>>>* with an empty (or null) outer list:
> {code:c++}arrow::MemoryPool* pool = arrow::default_memory_pool();
> arrow::Result<std::shared_ptr<arrow::io::BufferOutputStream>> stream_buffer =
>     arrow::io::BufferOutputStream::Create(1, pool);
> std::vector<std::shared_ptr<arrow::Field>> inner_list_field{std::make_shared<arrow::Field>("array_sub_col",arrow::list(arrow::utf8()))};
> // Datatype for the builder: list<struct<list<string>>>
> std::shared_ptr<DataType> data_type = list(struct_(inner_list_field));
> std::unique_ptr<arrow::ArrayBuilder> builder;
> arrow::MakeBuilder(pool, data_type, &builder);
> auto* list_builder = dynamic_cast<arrow::ListBuilder*>(builder.get());
> // Append a null or an empty list to the outer list
> list_builder->AppendNull(); // or list_builder->AppendEmptyValue()
> std::vector<std::shared_ptr<arrow::Array>> value_batch;
> value_batch.resize(1);
> list_builder->Finish(&value_batch[0]);
> std::vector<std::shared_ptr<arrow::Field>> outer_list_field{std::make_shared<arrow::Field>("array_1",data_type)};
> auto schema = std::make_shared<arrow::Schema>(outer_list_field);
> // Build a single row record batch
> std::shared_ptr<arrow::RecordBatch> batch = RecordBatch::Make(schema, 1, value_batch);
> ASSERT_OK(batch->Validate());
> // Stream the batch to a file to later read on the Java side
> arrow::Result<std::shared_ptr<ipc::RecordBatchWriter>> stream_writer = 
>     arrow::ipc::MakeStreamWriter(stream_buffer.ValueOrDie().get(), schema, arrow::ipc::IpcWriteOptions::Defaults());
> stream_writer.ValueOrDie()->WriteRecordBatch(*batch);
> arrow::Result<std::shared_ptr<arrow::Buffer>> buffer_result = stream_buffer.ValueOrDie()->Finish();
> std::shared_ptr<arrow::Buffer> buffer = buffer_result.ValueOrDie();
> auto file_output = arrow::io::FileOutputStream::Open("/tmp/batch_stream.out").ValueOrDie();
> file_output->Write(buffer->data(), buffer->size());
> file_output->Close();
> {code}
> As expected, Python holds the same memory layout for the field vectors as the code above:
> {code:python}array = pa.array([None], type=pa.list_(pa.struct([pa.field("array_sub_col", pa.list_(pa.utf8()))])))
> batch = pa.record_batch([struct_array], names=["array_1"])
> sink = pa.BufferOutputStream()
> with pa.ipc.new_stream(sink, batch.schema) as writer:
>     writer.write_batch(batch)
> buf = sink.getvalue()
> with open('/tmp/batch_stream.out', 'wb') as f:
>     f.write(buf)
> {code}
> *Java fails when then trying to access the inner list's field reader:*
> {code:java}File file = new File("/tmp/batch_stream.out");
> byte[] bytes = FileUtils.readFileToByteArray(file);
> try (ArrowStreamReader reader = new ArrowStreamReader(new ByteArrayInputStream(bytes), allocator)) {
>      Schema schema = reader.getVectorSchemaRoot().getSchema();
>      reader.loadNextBatch();
>      readBatch.getVector("array_1").getReader().reader().reader("array_sub_col");                     // <- fails: reader("array_sub_col") fails with OOB
>      // Concrete readers:
>      // FieldVector array_1 = readBatch.getVector("array_1");
>      // UnionListReader array_1_reader = (UnionListReader) array_1.getReader();
>      // NullableStructReaderImpl struct_reader = (NullableStructReaderImpl) array_1_reader.reader();
>      // FieldReader union_list_reader = struct_reader.reader("array_sub_col");                        // <- fails: OOB
> {code}
> h3. Stack trace:
> {noformat}
> java.lang.reflect.InvocationTargetException
>     at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
>     at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
>     at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
>     at java.lang.reflect.Method.invoke (Method.java:566)
>     at org.codehaus.mojo.exec.ExecJavaMojo$1.run (ExecJavaMojo.java:297)
>     at java.lang.Thread.run (Thread.java:829)
> Caused by: java.lang.IndexOutOfBoundsException: index: 4, length: 4 (expected: range(0, 4))
>     at org.apache.arrow.memory.ArrowBuf.checkIndexD (ArrowBuf.java:318)
>     at org.apache.arrow.memory.ArrowBuf.chk (ArrowBuf.java:305)
>     at org.apache.arrow.memory.ArrowBuf.getInt (ArrowBuf.java:424)
>     at com.test.arrow.ValidateArrow.testArrow (ValidateArrow.java:433)
>     at com.test.arrow.ValidateArrow.main (ValidateArrow.java:440)
>     at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0 (Native Method)
>     at jdk.internal.reflect.NativeMethodAccessorImpl.invoke (NativeMethodAccessorImpl.java:62)
>     at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke (DelegatingMethodAccessorImpl.java:43)
>     at java.lang.reflect.Method.invoke (Method.java:566)
>     at org.codehaus.mojo.exec.ExecJavaMojo$1.run (ExecJavaMojo.java:297)
>     at java.lang.Thread.run (Thread.java:829)
> {noformat}



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