GH-50431: [Python] Make FlightError a non-cdef class for abi3 wheel precursor

[mroeschke]

Rationale for this change

Towards #50398

closes #50431

What changes are included in this PR?

This is an agent generated PR that makes FlightError a non-cdef subclass of Exception as Cython does not support building with the Limited API and cdef classes that inherit from Python classes.

It appears before a cdef CStatus to_status was defined on each subclass to return a MakeFlightError per flight error flavor. This was pull out to a dedicated _flight_error_to_status function instead.

Are these changes tested?

Yes (via existing tests?)

Are there any user-facing changes?

No

• GitHub Issue: [Packaging] Support abi3 wheels for pyarrow #50398
• GitHub Issue: [Python] Make FlightError a non-cdef class #50431

[Copilot]

Pull request overview

This PR adjusts the Python Flight exception hierarchy to support building toward abi3 wheels by removing FlightError (and its key subclasses) as Cython cdef class types, since Cython limited-API builds can’t support cdef classes inheriting from Python classes like Exception.

Changes:

• Convert FlightError and its main subclasses from cdef class to regular Python class.
• Replace per-subclass to_status() Cython methods with a centralized _flight_error_to_status() helper that maps FlightError instances to the appropriate arrow::flight::MakeFlightError(...) status.
• Update all server/callback exception translation sites to use _flight_error_to_status(...) instead of casting and calling to_status().

[lidavidm]

It seems reasonable.

Is this the only change needed for the linked issue? It may be better to file this as a subissue?

[mroeschke]

It seems reasonable.

Is this the only change needed for the linked issue? It may be better to file this as a subissue?

Sure opened #50431 and linked it in the OP. (I don't think I have permissions to create subissues from the other linked issue)