ENH: compute hash without PYTHONHASHSED (#146)

* ENH: reuse `get_readable_hash()` from AmpForm v0.15.5
* MAINT: remove `PYTHONHASHSEED` explanations

.cspell.json

@@ -167,7 +167,6 @@
     "pyplot",
     "pyright",
     "pytest",
-    "PYTHONHASHSEED",
     "QRules",
     "recoupling",
     "recouplings",

.envrc

@@ -1,4 +1,2 @@
 uv sync --all-extras --quiet
 source .venv/bin/activate
-
-export PYTHONHASHSEED=0

.github/workflows/ci.yml

@@ -5,9 +5,6 @@ concurrency:
   cancel-in-progress: |-
     ${{ github.ref != format('refs/heads/{0}', github.event.repository.default_branch) }}
 
-env:
-  PYTHONHASHSEED: "0"
-
 on:
   push:
     branches:

.pre-commit-config.yaml

@@ -18,7 +18,6 @@ repos:
       - id: check-dev-files
         args:
           - --doc-apt-packages=graphviz
-          - --environment-variables=PYTHONHASHSEED=0
           - --github-pages
           - --repo-name=ampform-dpd
           - --repo-title=AmpForm-DPD

pyproject.toml

@@ -374,8 +374,6 @@ commands =
     pytest {posargs}
 description = Run all unit tests
 passenv = *
-setenv =
-    PYTHONHASHSEED = 0
 
 [testenv:cov]
 allowlist_externals =

src/ampform_dpd/io/__init__.py

@@ -28,10 +28,13 @@
 import cloudpickle
 import sympy as sp
 from ampform.io import aslatex
+from ampform.sympy._cache import (
+    get_readable_hash,  # noqa: PLC2701
+    get_system_cache_directory,  # noqa: PLC2701
+)
 from tensorwaves.function.sympy import create_function, create_parametrized_function
 
 from ampform_dpd import DefinedExpression
-from ampform_dpd._cache import get_readable_hash, get_system_cache_directory
 from ampform_dpd.decay import (
     IsobarNode,
     Particle,
@@ -269,10 +272,6 @@ def perform_cached_lambdify(  # type:ignore[misc]  # pyright:ignore[reportIncons
             directory will be put under the home directory, or to the path specified by
             the environment variable :code:`SYMPY_CACHE_DIR`.
 
-    .. tip:: For a faster cache, set `PYTHONHASHSEED
-        <https://docs.python.org/3/using/cmdline.html#envvar-PYTHONHASHSEED>`_ to a
-        fixed value.
-
     .. seealso:: :func:`ampform.sympy.perform_cached_doit`
     """
     if cache_directory is None:

tests/test_io.py

@@ -1,23 +1,8 @@
 # pyright: reportPrivateUsage=false
 from __future__ import annotations
 
-import logging
-import os
-import sys
-from os.path import abspath, dirname
-from typing import TYPE_CHECKING
-
-import pytest
-import sympy as sp
-
-from ampform_dpd._cache import _warn_about_unsafe_hash
 from ampform_dpd.decay import IsobarNode, Particle
-from ampform_dpd.io import aslatex, get_readable_hash
-
-if TYPE_CHECKING:
-    from _pytest.logging import LogCaptureFixture
-
-THIS_DIR = dirname(abspath(__file__))
+from ampform_dpd.io import aslatex
 
 # https://compwa-org--129.org.readthedocs.build/report/018.html#resonances-and-ls-scheme
 dummy_args = {"mass": 0, "width": 0}
@@ -50,36 +35,3 @@ def test_aslatex_isobar_node():
     node = IsobarNode(Λ1520, p, K, interaction=(2, 1))
     latex = aslatex(node)
     assert latex == R"\left(\Lambda(1520) \xrightarrow[S=1]{L=2} p K^-\right)"
-
-
-@pytest.mark.parametrize(
-    ("assumptions", "expected_hash"),
-    [
-        (dict(), (+7459658071388516764, +8778804591879682108)),
-        (dict(real=True), (+3665410414623666716, -7967572625470457155)),
-        (dict(rational=True), (-7926839224244779605, -8321323707982755013)),
-    ],
-)
-def test_get_readable_hash(
-    assumptions, expected_hash: tuple[int, int], caplog: LogCaptureFixture
-):
-    caplog.set_level(logging.WARNING)
-    x, y = sp.symbols("x y", **assumptions)
-    expr = x**2 + y
-    h = get_readable_hash(expr)
-    python_hash_seed = os.environ.get("PYTHONHASHSEED")
-    if python_hash_seed is None or not python_hash_seed.isdigit():
-        assert h[:7] == "bbc9833"
-        if _warn_about_unsafe_hash.cache_info().hits == 0:
-            assert "PYTHONHASHSEED has not been set." in caplog.text
-            caplog.clear()
-    elif python_hash_seed == "0":
-        if sys.version_info >= (3, 11):
-            expected_hash = expected_hash[1]  # type:ignore[assignment]
-        else:
-            expected_hash = expected_hash[0]  # type:ignore[assignment]
-        expected = f"pythonhashseed-0{expected_hash:+d}"
-        assert h == expected
-    else:
-        pytest.skip("PYTHONHASHSEED has been set, but is not 0")
-    assert not caplog.text