JoinSetTracerError is not exported from datafusion-common-runtime

[JanKaul]

Describe the bug

The JoinSetTracerError type is used in the public API of datafusion-common-runtime but is not exported, making it impossible for downstream users to properly handle errors from set_join_set_tracer().

To Reproduce

Try to use the crate from downstream code:

use datafusion_common_runtime::{set_join_set_tracer, JoinSetTracerError};
//                                                    ^^^^^^^^^^^^^^^^^^
//                                                    Not exported!

This fails because JoinSetTracerError is not in the public exports.

Expected behavior

Since set_join_set_tracer() returns Result<(), JoinSetTracerError>, users should be able to access JoinSetTracerError to handle errors properly.

Current code

In datafusion/common-runtime/src/lib.rs (line 33):

pub use trace_utils::{set_join_set_tracer, JoinSetTracer};

The function set_join_set_tracer is exported, but its error type JoinSetTracerError is not.

Suggested fix

Add JoinSetTracerError to the re-exports:

pub use trace_utils::{set_join_set_tracer, JoinSetTracer, JoinSetTracerError};

Additional context

• Location: https://github.com/apache/datafusion/blob/main/datafusion/common-runtime/src/lib.rs#L33
• The error type is defined in trace_utils.rs and is a proper public API component
• This affects anyone trying to set up custom tracing for JoinSet operations