[jira] [Created] (ARROW-18320) [C++] Flight client may crash due to improper Result/Status conversion

["David Li (Jira)" <ji...@apache.org>]

David Li created ARROW-18320:
--------------------------------

             Summary: [C++] Flight client may crash due to improper Result/Status conversion
                 Key: ARROW-18320
                 URL: https://issues.apache.org/jira/browse/ARROW-18320
             Project: Apache Arrow
          Issue Type: Bug
          Components: C++, FlightRPC
    Affects Versions: 6.0.0
            Reporter: David Li


Reported on user@ https://lists.apache.org/thread/84z329t1djhnbr5bq936v4hr8cyngj2l 

{noformat}
I have an issue on my project, we have a query execution engine that
returns result data as a flight stream and c++ client that receives the
stream. In case a query has no results but the result schema implies
dictionary encoded fields in results we have client app crushed.

The cause is in cpp/src/arrow/flight/client.cc:461:

::arrow::Result<std::unique_ptr<ipc::Message>> ReadNextMessage() override {
if (stream_finished_) {
return nullptr;
}
internal::FlightData* data;
{
auto guard = read_mutex_ ? std::unique_lock<std::mutex>(*read_mutex_)
: std::unique_lock<std::mutex>();
peekable_reader_->Next(&data);
}
if (!data) {
stream_finished_ = true;
return stream_->Finish(Status::OK()); // Here the issue
}
// Validate IPC message
auto result = data->OpenMessage();
if (!result.ok()) {
return stream_->Finish(std::move(result).status());
}
*app_metadata_ = std::move(data->app_metadata);
return result;
}

The method returns Result object while stream_Finish(..) returns a Status.
So there is an implicit conversion from Status to Result that causes
Result(Status) constructor to be called, but the constructor expects only
error statuses which in turn causes the app to be failed:

/// Constructs a Result object with the given non-OK Status object. All
/// calls to ValueOrDie() on this object will abort. The given `status` must
/// not be an OK status, otherwise this constructor will abort.
///
/// This constructor is not declared explicit so that a function with a
return
/// type of `Result<T>` can return a Status object, and the status will be
/// implicitly converted to the appropriate return type as a matter of
/// convenience.
///
/// \param status The non-OK Status object to initialize to.
Result(const Status& status) noexcept // NOLINT(runtime/explicit)
: status_(status) {
if (ARROW_PREDICT_FALSE(status.ok())) {
internal::DieWithMessage(std::string("Constructed with a non-error status: ")
+
status.ToString());
}
}

Is there a way to workaround or fix it? We use Arrow 6.0.0, but it seems
that the issue exists in all future versions.
{noformat}



--
This message was sent by Atlassian Jira
(v8.20.10#820010)