Add per-size tuple freelist (20 buckets × 2000 each) by youknowone · Pull Request #7361 · RustPython/RustPython

Implement PyTuple freelist matching tuples[PyTuple_MAXSAVESIZE]:
- TupleFreeList with 20 per-size buckets (sizes 1..=20, 2000 capacity each)
- freelist_push uses pre-clear size hint for correct bucket selection
- freelist_pop takes &Self payload to select bucket by size
- Type guard in new_ref handles structseq types sharing PyTuple vtable
- Add pyinner_layout<T>() helper for custom freelist Drop impls
- Update freelist_pop/push signatures across all freelist types

Move exact-type filtering from freelist_pop implementations to the
single call-site in new_ref. This prevents structseq and other subtypes
from popping tuple freelist entries entirely, rather than popping and
then deallocating on type mismatch.

Add Context::try_genesis() that returns None during bootstrap to avoid
deadlock when genesis() is called during Context initialization.

Remove typ parameter from freelist_push trait signature. The exact type
check is now done once at the call-site alongside the heaptype check,
simplifying all freelist_push implementations.

By calling freelist_push before tp_clear, the payload is still intact
and can be read directly (e.g. tuple element count for bucket selection).
This eliminates freelist_hint and the hint parameter entirely.

* Add per-size tuple freelist (20 buckets × 2000 each)

Implement PyTuple freelist matching tuples[PyTuple_MAXSAVESIZE]:
- TupleFreeList with 20 per-size buckets (sizes 1..=20, 2000 capacity each)
- freelist_push uses pre-clear size hint for correct bucket selection
- freelist_pop takes &Self payload to select bucket by size
- Type guard in new_ref handles structseq types sharing PyTuple vtable
- Add pyinner_layout<T>() helper for custom freelist Drop impls
- Update freelist_pop/push signatures across all freelist types

* freelist: exact type check at pop call-site

Move exact-type filtering from freelist_pop implementations to the
single call-site in new_ref. This prevents structseq and other subtypes
from popping tuple freelist entries entirely, rather than popping and
then deallocating on type mismatch.

Add Context::try_genesis() that returns None during bootstrap to avoid
deadlock when genesis() is called during Context initialization.

* Move exact type check from freelist_push to call-site in default_dealloc

Remove typ parameter from freelist_push trait signature. The exact type
check is now done once at the call-site alongside the heaptype check,
simplifying all freelist_push implementations.

* Remove freelist_hint; call freelist_push before tp_clear

By calling freelist_push before tp_clear, the payload is still intact
and can be read directly (e.g. tuple element count for bucket selection).
This eliminates freelist_hint and the hint parameter entirely.