Version

Python Semantic Versioning

• Single Class — A single Version class that handles semantic versioning.
• Full SemVer Support — Supports major, minor, patch, pre-release and build metadata
• Comparable — All six comparison operators are built in (<, <=, >, >=, ==, !=)
• Track Multiple Versions — Track multiple versions in a single instance.
• Increment — Bump major, minor, patch, or build with a single call.

Version is a lightweight Python library for working with Semantic Version (SemVer). It provides a single Version class that handles the full lifecycle of version strings — parsing, validating, comparing, and managing collections of them.

At its core, the library solves a common pain point: version strings look simple but have non-obvious ordering rules, especially once pre-release tags and build metadata are involved. Rather than reaching for a heavyweight dependency or writing fragile string comparisons, you get a focused tool that implements the SemVer 2.0.0 spec correctly and completely.

A Version can be created from a single string or a list of strings. When given a list, it automatically filters out anything malformed and sets itself to the highest valid entry. From there you can add, remove, and increment versions in the tracked set, inspect the full list, or ask for the latest at any time — with the current version always kept in sync as the tracked set changes.

Comparisons use all six standard operators and follow the spec's precedence rules precisely: numeric identifiers sort as integers, alphanumeric identifiers sort lexically, numeric identifiers rank below alphanumeric ones, a shorter pre-release ranks below a longer one with the same prefix, and any pre-release at all ranks below the equivalent release version.

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Installation

Install python-versioning using pip:

pip install python-versioning

Requirements: Python 3.7+

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Usage

First import:

from version import Version

Major, Minor, Patch

Define Version class with SemVer 1.4.2:

from version import Version

v = Version('1.4.2')
print(v.major)        # 1
print(v.minor)        # 4
print(v.patch)        # 2
print(v.version)      # '1.4.2'

Pre-release and build metadata

Define Version class with SemVer 2.0.0-alpha.1+build.42:

from version import Version

v = Version('2.0.0-alpha.1+build.42')
print(v.major)        # 2
print(v.minor)        # 0
print(v.patch)        # 0
print(v.pre_release)  # ['alpha', 1]
print(v.build)        # ['build', 42]
print(v.version)      # '2.0.0-alpha.1+build.42'

Compare versions

All six comparison operators are supported (<, <=, >, >=, ==, !=):

Version('1.0.0') < Version('2.0.0')       # True
Version('1.0.0-alpha') < Version('1.0.0') # True  (pre-release < release)
Version('1.0.0') == Version('1.0.0')      # True
Version('2.0.0') > Version('1.9.9')       # True

Comparing against a non-Version raises a TypeError:

Version('1.0.0') < '1.0.1'  # raises TypeError

Increment a version

Use the MAJOR, MINOR, PATCH, and BUILD constants with increment() to bump a version. The incremented version is added to the tracked list and becomes the current version.

from version import Version, MAJOR, MINOR, PATCH, BUILD

v = Version('1.2.3')

v.increment(PATCH)   # 1.2.4  — patch bumped
v.increment(MINOR)   # 1.3.0  — minor bumped, patch reset
v.increment(MAJOR)   # 2.0.0  — major bumped, minor and patch reset

Incrementing BUILD defaults to +b1 if no build metadata is set, otherwise it increments the trailing number:

v = Version('1.0.0')
v.increment(BUILD)   # 1.0.0+b1

v.increment(BUILD)   # 1.0.0+b2

v = Version('1.0.0+build.4')
v.increment(BUILD)   # 1.0.0+build.5

Pre-release is preserved when incrementing build:

v = Version('1.0.0-alpha')
v.increment(BUILD)   # 1.0.0-alpha+b1

Incrementing MAJOR, MINOR, or PATCH clears any pre-release and build metadata per the SemVer spec.

Track Multiple Versions

Initialize with a list and the object is automatically set to the latest valid version:

v = Version(['1.0.0', '3.2.1', '2.0.0-beta', 'not-a-version'])
print(v)  # '3.2.1'  — invalid entries are silently skipped

Add additional versions over time. If a new version is added that is higher than the current, it becomes the latest:

v = Version('1.0.0')
print(v.version)      # '1.0.0'

v.add('2.0.0')
print(v.version)      # '2.0.0'

v.add('1.5.0')
print(v.version)      # '2.0.0'

v.add('3.0.1')
print(v.version)      # '3.0.1'

Duplicates are ignored and invalid strings raise VersionError:

v.add('1.0.0')        # no-op, already tracked
v.add('bad-version')  # raises VersionError

Remove versions:

v = Version('1.0.0')
v.add('2.0.0')
v.remove('1.0.0')

Removing the only version raises VersionError:

v = Version('1.0.0')
v.remove('1.0.0')  # raises VersionError: Cannot remove this version

Removing the current version reverts to the next latest:

v = Version('1.0.0')
v.add('2.0.0')
v.add('2.1.0')
print(v.version)      # '2.1.0'

v.remove('2.1.0')
print(v.version)      # '2.0.0'

Get the latest tracked version

latest returns the highest version string in the tracked list:

v = Version('1.0.0')
v.add('3.0.0')
v.add('2.0.0')
print(v.latest)       # '3.0.0'
print(type(v.latest)) # <class 'str'>

Inspect all tracked versions

versions returns all tracked versions as Version objects, sorted highest first:

v = Version(['1.0.0', '2.0.0', '3.0.0'])
for version in v.versions:
    print(version)
# 3.0.0
# 2.0.0
# 1.0.0

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Comparison Rules

This library follows the SemVer 2.0.0 specification exactly:

1. Major, minor, patch are compared numerically.
2. Pre-release versions have lower precedence than the release version (1.0.0-alpha < 1.0.0).
3. When both versions have a pre-release, identifiers are compared left to right:
   • Numeric identifiers are compared as integers.
   • Alphanumeric identifiers are compared lexically.
   • Numeric identifiers always have lower precedence than alphanumeric ones (1 < alpha).
   • A shorter pre-release has lower precedence than a longer one with the same prefix (alpha < alpha.1).
4. Build metadata follows the same ordering rules as pre-release, and a version with build metadata has lower precedence than one without.

The full canonical precedence order from the SemVer spec:

1.0.0-alpha
1.0.0-alpha.1
1.0.0-alpha.beta
1.0.0-beta
1.0.0-beta.2
1.0.0-beta.11
1.0.0-rc.1
1.0.0

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Error Handling

VersionError is raised for any invalid version string:

Version('')           # VersionError: invalid version ''
Version('v1.0.0')     # VersionError: invalid version 'v1.0.0'
Version('1.0')        # VersionError: invalid version '1.0'
Version([])           # VersionError: No versions provided in the list
Version(['bad'])      # VersionError: No valid versions found in the list

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API Reference

Version(version: str | list[str])

Creates a Version instance.

• If given a string, parses and validates it.
• If given a list, filters out invalid entries, raises if none remain, and sets the instance to the highest valid version.

Attribute / Property	Type	Description
major	int	Major version number
minor	int	Minor version number
patch	int	Patch version number
pre_release	list[int | str]	Parsed pre-release identifiers
build	list[int | str]	Parsed build metadata identifiers
version	str	String form of this version
versions	list[Version]	All tracked versions as Version objects, sorted highest first
latest	str	Highest version string in the tracked list

Version.add(version: str) -> None

Adds a version string to the tracked list. No-op if already present. Raises VersionError if the string is invalid. Updates the current version if the new one is higher.

Version.remove(version: str) -> None

Removes a version string from the tracked list. Raises VersionError if the version is not tracked or if it is the only version remaining. If the removed version was the current version, the next highest becomes current.

Version.increment(part: str) -> None

Bumps the specified part of the version using one of the exported constants:

Constant	Effect
MAJOR	Increments major, resets minor and patch to 0, clears pre-release and build
MINOR	Increments minor, resets patch to 0, clears pre-release and build
PATCH	Increments patch, clears pre-release and build
BUILD	Increments build metadata; defaults to +b1 if none is set

The new version is appended to the tracked list and becomes the current version. Raises ValueError for an unrecognised part.

VersionError

Subclass of Exception. Raised when a version string does not conform to the SemVer format, or when a tracked-list operation cannot be completed (e.g. removing the last version).

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Run Tests

100/100 tests passed

python -m pytest tests/test.py -v