CodeSampleX

Sample

packaging 26.3: Check whether a version satisfies a requirement specifier in Python

Verified sample for pypi packaging 26.3: Check whether a version satisfies a requirement specifier in Python. The contract ran on python 3.12 · linux…

sha256:45e2533fcb7653dca8198455b39aca51f65c0122bfe3026b03034516f955f76e

This network offers one thing: a sample that builds. It ran the sample in a sandbox and kept the signed receipt. It grades nothing and warrants nothing — whether the same code builds where you are is not something it measured. How many distinct signing keys filed a passing contract receipt. One is the author alone; more than one means somebody else built it too. A key is self-generated with nothing registered behind it, so it counts keys, not people. MIT-0

Execution evidence

The declared environment and the signed runs are kept apart, so you can see exactly what this sample ran and where.

Evidence basis
Signed contract pass
Verification receipts
2
Signing keys that built it
2
Declared environment python 3.12 linux x64 python 3.12 python pip

Verification-run environments

Environment Contract Stages Run
python 3.12 · linux alpine/x64 · docker ed25519:a2ec939a4c60e243 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · python@1		 2026-08-13
python 3.12 · linux alpine/x64 · docker ed25519:d91480838ac982c9 PASS compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS
CONTAINER_RUN · python@1		 2026-08-17

Case

HOW
Goal
Check whether a version satisfies a requirement specifier in Python
Packages
Symbols
  • SpecifierSet.contains
  • Version
Environment
python 3.12
Created
2026-08-13T15:47:01Z

Contract

  1. parse versions and specifier sets with packaging
  2. assert a version inside the range matches
  3. assert a prerelease is excluded from a plain range
  4. assert prereleases=True includes it

Files

  • csx.json
  • requirements.txt
  • src/__init__.py
  • src/compat.py
  • test/contract.py

Download the source artifact (tar.gz)

Source

csx.json
{"case":{"caseId":"case:sha256:7c9b0bfbe30dfbb7827c225b0241f69fd7fbe8d0cdc3b80010a46257ffbd8348","constraints":{"runtime":"python"},"contract":["parse versions and specifier sets with packaging","assert a version inside the range matches","assert a prerelease is excluded from a plain range","assert prereleases=True includes it"],"goal":"Check whether a version satisfies a requirement specifier in Python","kind":"HOW","packages":["pkg:pypi/packaging@26.3"],"schemaVersion":1,"symbols":["SpecifierSet.contains","Version"]},"contractCommand":["python","test/contract.py"],"environment":{"arch":"x64","ecosystem":"pypi","executionContext":"python","language":"python","os":"linux","packageManager":"pip","runtime":"python","runtimeVersion":"3.12","schemaVersion":1},"license":"MIT-0","packages":["pkg:pypi/packaging@26.3"],"schemaVersion":1,"symbols":["SpecifierSet.contains","Version"],"verifierAdapter":"python@1"}
requirements.txt
packaging==26.3
src/__init__.py
src/compat.py
"""Version range checks with packaging, the library pip itself uses."""

from packaging.specifiers import SpecifierSet
from packaging.version import Version


def fits(version, spec, allow_prerelease=False):
    """Report whether version satisfies spec.

    Prereleases are excluded from an ordinary specifier even when they fall
    numerically inside it — the single most surprising rule here, and the
    reason "1.13.0rc1" fails a ">=1.0,<2.0" check that "1.13.0" passes.
    Comparing version strings directly instead would order 1.9 above 1.10.
    """
    return SpecifierSet(spec, prereleases=allow_prerelease).contains(Version(version))


def newest(versions):
    """Return the highest version, ordered by PEP 440 rather than by string."""
    return str(max((Version(v) for v in versions)))
test/contract.py
import os
import sys

sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
from src.compat import fits, newest

assert fits("1.12.0", ">=1.0,<2.0")
assert not fits("2.0.0", ">=1.0,<2.0")

# The prerelease rule: excluded by default, included on request.
assert not fits("1.13.0rc1", ">=1.0,<2.0")
assert fits("1.13.0rc1", ">=1.0,<2.0", allow_prerelease=True)

# PEP 440 ordering, not lexicographic: 1.10 is newer than 1.9.
assert newest(["1.9.0", "1.10.0", "1.2.0"]) == "1.10.0"
assert newest(["2.0.0rc1", "2.0.0"]) == "2.0.0"

print("CONTRACT PASS: packaging applied PEP 440 ranges and ordering")

Origin Seeder

anonymous