Python, dependency and compatibility policy¶
This is the current release-preparation evidence and compatibility policy. The API inventory describes present interfaces; the roadmap separates completed work from release preparation.
Runtime boundary¶
Mathematical implementations stay pure Python. Standard-library math, ctypes,
random, struct and other utilities are allowed. NumPy, Cython, compiled
mathematical extensions, native SIMD backends and mandatory numerical frameworks
are excluded. The existing runtime dependency is six; its compatibility helpers
remain in use. Reducing runtime dependencies is a long-term objective, not
permission to remove six before evaluating interpreter compatibility.
ctypes is standard-library interoperability, not an accelerated mathematical
backend. Matrix.c_matrix is a row-major float32 snapshot of Python storage.
Constructor and supported in-place matrix operations refresh it; direct external
list edits do not. Do not change its type, order or ownership as an optimization.
Foreign rendering consumers must explicitly reconcile their upload layout and
transpose conventions; no OpenGL driver support claim follows from a ctypes test.
Verified evidence and unverified targets¶
| Interpreter/platform | Evidence | Policy status |
|---|---|---|
| CPython 3.10.21, 3.11.16, 3.12.14, 3.13.5, 3.14.7; Linux x86_64; six 1.17.0 | Phase 5A full suite and installed wheel/sdist checks | Tested modern release matrix; keep testing maintained patch versions |
| PyPy and other implementations | No executed interpreter run | Unverified |
| Python 2.7 | Source contains unsupported syntax and standard-library calls; no interpreter available | Unsupported; classifiers removed, no compatibility rewrite |
| Python 3.2–3.9 | Historical metadata is not evidence; minimum is now 3.10 | Unsupported |
| Windows, macOS and other architectures | No executed platform matrix | Unverified; pure-Python wheel is not proof of platform testing |
Python 2.7 assessment¶
Retaining six does not make the core Python-2 compatible. SH contains
raise ... from None, imports functools.lru_cache, and calls math.isqrt.
Bezier uses variadic math.hypot and math.isfinite. These have concrete
Python 2.7 syntax or library incompatibilities. No Python 2.7 interpreter was
available for execution, and no compatibility pass is claimed.
The pinned audit tooling uses pytest 9 (Python >=3.10). The chosen 3.10 minimum provides a single executed runtime/test matrix without rewriting mathematics to serve end-of-life interpreters. Python 3.8/3.9 may support some core functions but are outside the declared and tested range; that is a support-policy boundary, not a claim that every import necessarily fails there.
Packaging, platform and numeric reproducibility¶
The distribution and import namespace remain gem. Version 1.0.0 has one source,
gem._version.__version__, and is exposed as gem.__version__. Metadata is in
pyproject.toml; setup.py is a compatibility entry point.
The only runtime dependency remains six. The pure-Python wheel includes all
core modules and existing transitional gem.experimental reexports. The sdist
includes documentation and verification sources. See the
packaging policy for contents and release blockers.
The historical .travis.yml is not an active support matrix:
its launcher.py test prints examples and does not run pytest. Current packaging
checks use real pytest, built artifacts and isolated imports; the new GitHub
workflow is a repeatable check, not evidence that a remote CI run has completed.
Python float calculations ordinarily use binary64; caller numeric types are not uniformly coerced, and no arbitrary-precision public contract is established. ctypes exports use binary32 and may round or overflow independently of Python results. Raw angular probes are native-endian float32 RGB: convert endianness explicitly when exchanging files across platforms.
Use independent references and operation-specific tolerances; do not impose a single epsilon on every domain. Exact Vector equality stays exact. Matrix inverse singularity detection has no arbitrary near-singular threshold. Stable finite norms/inverses do not imply stable determinants, dot products or every quaternion operation at extreme scales. Numerical, integration and truncation limits are described in conventions.
libm/interpreter rounding and zlib output can differ across systems. HDR image hashes are a same-environment reproducibility check; coefficient, linear-pixel and mathematical-reference tests remain the portable oracle. Performance captures from different environments are not controlled comparisons.
API preservation and versioning¶
Preserve current names, signatures, return types, caller ownership, receiver mutation and mathematical conventions. Float-only Matrix/Quaternion wrapper division, mixed angle units, misspelled methods and legacy forward axes remain intentional compatibility obligations until explicitly reviewed. Returning methods usually allocate fresh storage; constructors and explicit accessors are exceptions.
Version 1.0.0 is prepared for review, not published. The release versioning policy uses semantic versioning: additive compatible interfaces in minor releases, compatible fixes in patches, and incompatible removals/changes at a declared major boundary. Numerical corrections still need explicit compatibility notes. Unsupported domains do not acquire new guarantees from the version number.
Transitional imports retain one canonical implementation. No runtime deprecation warnings or removal date are introduced. Retiring their paths requires a release boundary, compatibility window and migration plan; see the existing migration table. The removed E07 transport module has no replacement. This phase changes neither shims nor licensing.