tealet-greenlet

tealet-greenlet: greenlet compatibility on top of tealet.

tealet-greenlet packages the greenlet-compatible layer separately from the core tealet runtime. The core package provides stack-slicing primitives; this package carries the larger greenlet compatibility surface, including parent/child switching, tracing hooks, context handling, and upstream-style compatibility tests.

Rationale

tealet-greenlet is an experimental replacement library for greenlet based on the tealet engine. It is currently intended as a proof of concept: how much of greenlet's behaviour can we express by keeping the low-level stack engine small, portable, and focused, while putting the greenlet business logic in a separate layer?

That split is the point. tealet benefits from a simple core API and the portability work already done in libtealet and Stackman. tealet-greenlet then adds the compatibility policy on top: parent selection, error translation, context handling, tracing hooks, cleanup behaviour, and test-facing implementation probes.

Future development may keep improving the Python implementation, or move hot paths and tricky compatibility edges into a C-accelerated core if that turns out to be worthwhile. For now, the package gives us a concrete compatibility target without making the core tealet wheel carry all of greenlet's semantic cargo.

Installation

python -m pip install tealet-greenlet

The canonical import is tealet_greenlet:

from tealet_greenlet import greenlet, getcurrent

Need drop-in import greenlet compatibility? Install the shim into sys.modules before importing code that expects upstream greenlet:

import tealet_greenlet

tealet_greenlet.install()

import greenlet

For transition from the old in-core location, tealet.greenlet remains as a thin wrapper when this package is installed.

Status

tealet-greenlet is pre-1.0 software. It is useful for experimentation, tracking compatibility, and testing the architecture, but it does not claim full upstream greenlet parity yet.

Documentation

• Python API
• Architecture
• Upstream compatibility tests

The historical 2014-era greenlet_legacy.py shim is kept under tests/ as a comparison fixture. It is not part of the installable package API.

Tests

Run the package-local tests from the repository root:

uv run --active python -m pytest packages/tealet-greenlet/tests -q

The upstream compatibility tests are opt-in:

PYTEALET_RUN_UPSTREAM_GREENLET_TESTS=1 \
  uv run --active python -m pytest packages/tealet-greenlet/tests/compat_greenlet -q