Version comparison library that offers utilities, version constraint parsing and validation.

It follows semver (semantic versioning) where possible but is also constrained by version_compare and backwards compatibility and as such cannot implement semver strictly.

Originally written as part of composer/composer, now extracted and made available as a stand-alone library.

Install the latest version with:

composer require composer/semver

• PHP 5.3.2 is required but using the latest version of PHP is highly recommended.

For details on how versions are compared, refer to the Versions article in the documentation section of the getcomposer.org website.

The Composer\Semver\VersionParser class provides the following methods for parsing, normalizing and validating versions and constraints.

Numeric versions are normalized to a 4 component versions (e.g. 1.2.3 is normalized to 1.2.3.0) for internal consistency and compatibility with version_compare. Normalized versions are used for constraints internally but should not be shown to end users.

For versions:

• isValid($version)
• normalize($version, $fullVersion = null)
• normalizeBranch($name)
• normalizeDefaultBranch($name)

For constraints:

• parseConstraints($constraints)

For stabilities:

• parseStability($version)
• normalizeStability($stability)

The Composer\Semver\Comparator class provides the following methods for comparing versions:

• greaterThan($v1, $v2)
• greaterThanOrEqualTo($v1, $v2)
• lessThan($v1, $v2)
• lessThanOrEqualTo($v1, $v2)
• equalTo($v1, $v2)
• notEqualTo($v1, $v2)

Each function takes two version strings as arguments and returns a boolean. For example:

use Composer\Semver\Comparator;

Comparator::greaterThan('1.25.0', '1.24.0'); // 1.25.0 > 1.24.0

The Composer\Semver\Semver class provides the following methods:

• satisfies($version, $constraints)
• satisfiedBy(array $versions, $constraint)
• sort($versions)
• rsort($versions)

The Composer\Semver\Intervals static class provides a few utilities to work with complex constraints or read version intervals from a constraint:

use Composer\Semver\Intervals;

// Checks whether $candidate is a subset of $constraint
Intervals::isSubsetOf(ConstraintInterface $candidate, ConstraintInterface $constraint);

// Checks whether $a and $b have any intersection, equivalent to $a->matches($b)
Intervals::haveIntersections(ConstraintInterface $a, ConstraintInterface $b);

// Optimizes a complex multi constraint by merging all intervals down to the smallest
// possible multi constraint. The drawbacks are this is not very fast, and the resulting
// multi constraint will have no human readable prettyConstraint configured on it
Intervals::compactConstraint(ConstraintInterface $constraint);

// Creates an array of numeric intervals and branch constraints representing a given constraint
Intervals::get(ConstraintInterface $constraint);

// Clears the memoization cache when you are done processing constraints
Intervals::clear()

See the class docblocks for more details.

composer/semver is licensed under the MIT License, see the LICENSE file for details.