[JAX] Move ffi type definition before ffi target definitions

[jberchtold-nvidia]

Description

Fixes issue that has occurred on most recent versions of nightly JAX/XLA

jax.errors.JaxRuntimeError: FAILED_PRECONDITION: Types used by FFI handlers must be registered before the handler registration

Type of change

• Documentation change (change only to the documentation, either a fix or a new content)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Infra/Build change
• Code refactoring

Changes

• Fix registration order

Checklist:

• I have read and followed the contributing guidelines
• The functionality is complete
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[jberchtold-nvidia]

/te-ci L1 jax

[greptile-apps]

Greptile Summary

The PR corrects JAX FFI initialization order so the optional EpInstanceState custom type is registered before FFI handlers that reference it.

• Moves FFI target registration after custom-type registration.
• Preserves conditional behavior for builds without NCCL EP support.
• Documents the ordering requirement inline.

Confidence Score: 5/5

The PR appears safe to merge, with no actionable defects identified in the registration-order change.

The optional type remains correctly guarded for non-EP builds, while EP builds now register EpInstanceState before all handlers that may reference it.

Important Files Changed

Filename	Overview
transformer_engine/jax/cpp_extensions/base.py	Reorders custom-type and target registration to satisfy newer JAX/XLA preconditions without changing the target set or non-EP behavior.

_{Reviews (1): Last reviewed commit: "Move ffi type definition before ffi targ..." | Re-trigger Greptile}