packvers

What it is and what it does

packvers is a fork of the Python packaging library created to preserve support for LegacyVersion and LegacySpecifier classes that were deprecated and removed from the main packaging project. It provides a complete set of utilities for working with Python package metadata according to established interoperability specifications such as PEP 440 (version handling) and PEP 425 (platform tags).

The package implements version parsing and comparison, version specifiers (e.g., '>=1.0'), environment markers for conditional dependencies, requirement parsing, platform tag handling, and general packaging utilities. It is intended for projects that still need to handle legacy version formats or require a stable snapshot of packaging functionality from an earlier point in time. The single runtime dependency is pyparsing, and the package supports Python 3.6 through 3.10 on CPython and PyPy.

Use it for:

• Parse and compare legacy version strings that do not conform to PEP 440 in older codebases.
• Build package management or distribution tools that need stable, frozen packaging utilities.
• Handle platform-specific wheel tags and environment markers for dependency resolution.
• Work with requirement specifications and version constraints in package metadata.
• Maintain compatibility with systems that depend on LegacyVersion semantics.

Worth the install?

AI-flagged interpretation of the facts on this page — verify before relying

Provides core utilities for Python package version handling, specifiers, markers, requirements, and tags, with continued support for LegacyVersion that was dropped from the upstream packaging library.

Yes, if you specifically need LegacyVersion support or require a stable snapshot of packaging utilities. The package is production-stable, permissively licensed, and has no known vulnerabilities. However, it is dormant—no updates since late 2022—so do not expect active maintenance or bug fixes. Install only if you have a concrete reason to use this fork rather than the current upstream packaging library.

Install

packvers on PyPI

pip install packvers

uv add packvers

poetry add packvers

Installing packvers

Before you install

Low install friction with a single runtime dependency (pyparsing). Maintenance is dormant—last release was 2022-12-22 and no commits since 2024-08-21—so expect no active bug fixes or updates, though the package is marked Production/Stable.

License in practice

Dual-licensed under BSD-2-Clause or Apache-2.0, both permissive licenses. You may use, modify, and distribute this package with minimal restrictions, though you should include a copy of the applicable license.

Quickstart

pip install packvers

from packvers.version import Version, LegacyVersion
from packvers.specifiers import SpecifierSet

v = Version('1.0.0')
legacy = LegacyVersion('1.0')
spec = SpecifierSet('>=1.0,<2.0')

Requires Python 3.6 or later; does not support Python 2.7.

Verify before relying

• Whether LegacyVersion and LegacySpecifier are fully compatible with the upstream packaging library's deprecated versions.
• Current maintenance status and likelihood of future updates or security patches.
• Whether this fork is actively used by projects that depend on it or if it is primarily a historical workaround.

Package facts

Evidence: packvers-21.5-py3-none-any.whl

Tags

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