[jira] [Created] (ARROW-6006) [C++] Error reading an empty IPC stream with a dictionary-encoded column

["Steven Fackler (JIRA)" <ji...@apache.org>]

Steven Fackler created ARROW-6006:
-------------------------------------

             Summary: [C++] Error reading an empty IPC stream with a dictionary-encoded column
                 Key: ARROW-6006
                 URL: https://issues.apache.org/jira/browse/ARROW-6006
             Project: Apache Arrow
          Issue Type: Bug
            Reporter: Steven Fackler


 
{code:java}
#include <arrow/api.h>
#include <arrow/ipc/api.h>
#include <arrow/io/api.h>
void check(arrow::Status status) {
 if (!status.ok()) {
 status.Abort();
 }
}
int main() {
 auto type = arrow::dictionary(arrow::int8(), arrow::utf8());
 auto f0 = arrow::field("f0", type);
 auto schema = arrow::schema({f0});
std::shared_ptr<arrow::io::BufferOutputStream> os;
 check(arrow::io::BufferOutputStream::Create(0, arrow::default_memory_pool(), &os));
std::shared_ptr<arrow::ipc::RecordBatchWriter> writer;
 check(arrow::ipc::RecordBatchStreamWriter::Open(&*os, schema, &writer));
 check(writer->Close());
std::shared_ptr<arrow::Buffer> buffer;
 check(os->Finish(&buffer));
arrow::io::BufferReader is(buffer);
std::shared_ptr<arrow::ipc::RecordBatchReader> reader;
 check(arrow::ipc::RecordBatchStreamReader::Open(&is, &reader));
std::shared_ptr<arrow::RecordBatch> batch;
 check(reader->ReadNext(&batch));
}
{code}
 
{noformat}
-- Arrow Fatal Error --
Invalid: Expected message in stream, was null or length 0{noformat}
It seems like this was caused by [https://github.com/apache/arrow/commit/e68ca7f9aed876a1afcad81a417afb87c94ee951], which moved the dictionary values from the DataType to the array itself.

I initially thought I could work around this by writing a zero-length table but that doesn't seem to actually work.

 



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