semver

Semantic Versioning library for Kotlin Multiplatform. It implements the full semantic version 2.0.0 specification and provides the ability to parse, compare, and increment semantic versions along with validation against constraints.

Install with Gradle

The library is available in Maven Central, so you have to add it to your repositories.

repositories {
    mavenCentral()
}

Then, you can add the package to your dependencies.

val semverVersion: String by project

dependencies {
    implementation("io.github.z4kn4fein:semver:$semverVersion")
}

In case of a multiplatform project, you can simply reference the package in your commonMain source set.

val semverVersion: String by project

kotlin {
    sourceSets {
        val commonMain by getting {
            dependencies {
                implementation("io.github.z4kn4fein:semver:$semverVersion")
            }
        }
    }
}

You can also use platform-specific packages that you can find here for each supported platform.

Usage

The following options are available to construct a Version:

• Building part by part.

   Version(major = 3, minor = 5, patch = 2, preRelease = "alpha", buildMetadata = "build")

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• Parsing from a string with Version.parse().

   Version.parse("3.5.2-alpha+build")

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• Using the toVersion() or toVersionOrNull() extension method on a string.

   "3.5.2-alpha+build".toVersion()

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The constructed Version object provides the following information:

val version = "3.5.2-alpha.2+build".toVersion()
version.major           // 3
version.minor           // 5
version.patch           // 2
version.preRelease      // "alpha.2"
version.buildMetadata   // "build"

version.isPreRelease    // true
version.isStable        // false
version.toString()      // "3.5.2-alpha.2+build"

version.withoutSuffixes().toString()   // "3.5.2"

Destructuring

Version supports destructuring by its public properties.

val version = "2.3.1-alpha.2+build".toVersion()
val (major, minor, patch, preRelease, buildMetadata) = version 

// major: 2
// minor: 3
// patch: 1
// preRelease: "alpha.2"
// buildMetadata: "build"

Strict vs. Loose Parsing

By default, the version parser considers partial versions like 1.0 and versions starting with the v prefix invalid. This behaviour can be turned off by setting the strict parameter to false.

"v2.3-alpha".toVersion()                    // exception
"2.0".toVersion()                           // exception

"v2.3-alpha".toVersion(strict = false)      // 2.3.0-alpha
"2".toVersion(strict = false)               // 2.0.0

Compare

It is possible to compare two Version objects with comparison operators or with the .compareTo() method.

"0.1.0".toVersion() < "0.1.1".toVersion()                   // true
"0.1.1".toVersion() <= "0.1.1".toVersion()                  // true
"0.1.0-alpha.3".toVersion() < "0.1.0-alpha.4".toVersion()   // true

"0.1.1".toVersion().compareTo("0.1.0".toVersion())          //  1
"0.1.0".toVersion().compareTo("0.1.1".toVersion())          // -1
"0.1.1".toVersion().compareTo("0.1.1".toVersion())          //  0

The equality of two Version objects can be determined with equality operators or with the equals() method.

"0.1.1".toVersion() == "0.1.1".toVersion()       // true
"0.1.1".toVersion() != "0.1.1".toVersion()       // false

"0.1.1".toVersion().equals("0.1.1".toVersion())  // true
"0.1.0".toVersion().equals("0.1.1".toVersion())  // false

Sort

As Version objects are comparable, you can get a sorted collection from them.

val list: List<Version> = listOf(
    "1.0.1".toVersion(),
    "1.0.1-alpha".toVersion(),
    "1.0.1-alpha.beta".toVersion(),
    "1.0.1-alpha.3".toVersion(),
    "1.0.1-alpha.2".toVersion(),
    "1.1.0".toVersion(),
    "1.1.0+build".toVersion(),
).sorted()

// The result:
//   "1.0.1-alpha"
//   "1.0.1-alpha.2"
//   "1.0.1-alpha.3"
//   "1.0.1-alpha.beta"
//   "1.0.1"
//   "1.1.0"
//   "1.1.0+build"

Range

Having an order provides the ability to determine whether a Version is in the range between two other versions.

val range = "1.0.0".toVersion().."1.1.0".toVersion()

"1.0.1".toVersion() in range     // true
"1.1.1".toVersion() in range     // false

Constraints

With constraints, it's possible to validate whether a version satisfies a set of rules or not. A constraint can be described as one or more conditions combined with logical OR and AND operators.

Conditions

Conditions are usually composed of a comparison operator and a version like >=1.2.0. The condition >=1.2.0 would be met by any version that greater than or equal to 1.2.0.

Supported comparison operators:

• = Equal (equivalent to no operator: 1.2.0 means =1.2.0)

• != Not equal

• < Less than

• <= Less than or equal

• > Greater than

• >= Greater than or equal

Conditions can be joined together with whitespace, representing the AND logical operator between them. The OR operator can be expressed with || or | between condition sets.

For example, the constraint >=1.2.0 <3.0.0 || >4.0.0 translates to: Only those versions are allowed that are either greater than or equal to 1.2.0 {AND} less than 3.0.0 {OR} greater than 4.0.0.

We can notice that the first part of the previous constraint (>=1.2.0 <3.0.0) is a simple semantic version range. There are more ways to express version ranges; the following section will go through all the available options.

Range Conditions

There are particular range indicators which are sugars for more extended range expressions.

• X-Range: The x, X, and * characters can be used as a wildcard for the numeric parts of a version.

  • 1.2.x translates to >=1.2.0 <1.3.0-0

  • 1.x translates to >=1.0.0 <2.0.0-0

  • * translates to >=0.0.0

  In partial version expressions, the missing numbers are treated as wildcards.

• 1.2 means 1.2.x which finally translates to >=1.2.0 <1.3.0-0

• 1 means 1.x or 1.x.x which finally translates to >=1.0.0 <2.0.0-0

• Hyphen Range: Describes an inclusive version range. Wildcards are evaluated and taken into account in the final range.

• 1.0.0 - 1.2.0 translates to >=1.0.0 <=1.2.0

• 1.1 - 1.4.0 means >=(>=1.1.0 <1.2.0-0) <=1.4.0 which finally translates to >=1.1.0 <=1.4.0

• 1.1.0 - 2 means >=1.1.0 <=(>=2.0.0 <3.0.0-0) which finally translates to >=1.1.0 <3.0.0-0

• Tilde Range (~): Describes a patch level range when the minor version is specified or a minor level range when not.

• ~1.0.1 translates to >=1.0.1 <1.1.0-0

• ~1.0 translates to >=1.0.0 <1.1.0-0

• ~1 translates to >=1.0.0 <2.0.0-0

• ~1.0.0-alpha.1 translates to >=1.0.1-alpha.1 <1.1.0-0

• Caret Range (^): Describes a range with regard to the most left non-zero part of the version.

• ^1.1.2 translates to >=1.1.2 <2.0.0-0

• ^0.1.2 translates to >=0.1.2 <0.2.0-0

• ^0.0.2 translates to >=0.0.2 <0.0.3-0

• ^1.2 translates to >=1.2.0 <2.0.0-0

• ^1 translates to >=1.0.0 <2.0.0-0

• ^0.1.2-alpha.1 translates to >=0.1.2-alpha.1 <0.2.0-0

Validation

The following options are available to construct a Constraint:

• Parsing from a string with Constraint.parse().

   Constraint.parse(">=1.2.0")

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• Using the toConstraint() or toConstraintOrNull() extension method on a string.

   ">=1.2.0".toConstraint()

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Let's see how we can determine whether a version satisfies a constraint or not.

val constraint = ">=1.2.0".toConstraint()
val version = "1.2.1".toVersion()

version satisfies constraint        // true
constraint satisfiedBy version      // true

It's also possible to validate against a collection of constraints.

val constraints = listOf(">=1.2.0", "<2.0.0").map { it.toConstraint() }
val version = "1.2.1".toVersion()

version satisfiesAll constraints       // true
version satisfiesAny constraints       // true

With satisfiesAll the version must satisfy each constraint within the collection. With satisfiesAny it must satisfy at least one constraint to pass the validation.

Or to validate a collection of versions.

val constraint = ">=1.2.0".toConstraint()
val versions = listOf("1.2.1", "1.1.0").map { it.toVersion() }

constraint satisfiedByAll versions       // false
constraint satisfiedByAny versions       // true

With satisfiedByAll the constraint must be satisfied by each version within the collection. With satisfiedByAny it must be satisfied by at least one version to pass the validation.

Increment

Version objects can produce incremented versions of themselves with the nextMajor(), nextMinor(), nextPatch(), nextPreRelease(), and inc() methods. These methods can be used to determine the next version in order by increasing the appropriate identifier. Version objects are immutable, so each incrementing function creates a new Version.

This example shows how the incrementation works on a stable version:

val stableVersion = "1.0.0".toVersion()

val nextMajor = stableVersion.nextMajor()                               // 2.0.0
val nextMinor = stableVersion.nextMinor()                               // 1.1.0
val nextPatch = stableVersion.nextPatch()                               // 1.0.1
val nextPreRelease = stableVersion.nextPreRelease()                     // 1.0.1-0

// or with the inc() method:
val incrementedByMajor = stableVersion.inc(by = Inc.MAJOR)              // 2.0.0
val incrementedByMinor = stableVersion.inc(by = Inc.MINOR)              // 1.1.0
val incrementedByPatch = stableVersion.inc(by = Inc.PATCH)              // 1.0.1
val incrementedByPreRelease = stableVersion.inc(by = Inc.PRE_RELEASE)   // 1.0.1-0

In case of an unstable version:

val unstableVersion = "1.0.0-alpha.2+build.1".toVersion()

val nextMajor = unstableVersion.nextMajor()                               // 2.0.0
val nextMinor = unstableVersion.nextMinor()                               // 1.1.0
val nextPatch = unstableVersion.nextPatch()                               // 1.0.0
val nextPreRelease = unstableVersion.nextPreRelease()                     // 1.0.0-alpha.3

// or with the inc() method:
val incrementedByMajor = unstableVersion.inc(by = Inc.MAJOR)              // 2.0.0
val incrementedByMinor = unstableVersion.inc(by = Inc.MINOR)              // 1.1.0
val incrementedByPatch = unstableVersion.inc(by = Inc.PATCH)              // 1.0.0
val incrementedByPreRelease = unstableVersion.inc(by = Inc.PRE_RELEASE)   // 1.0.0-alpha.3

Each incrementing function provides the option to set a pre-release identity on the incremented version.

val version = "1.0.0-alpha.1".toVersion()

val nextPreMajor = version.nextMajor(preRelease = "beta")           // 2.0.0-beta
val nextPreMinor = version.nextMinor(preRelease = "")               // 1.1.0-0
val nextPrePatch = version.nextPatch(preRelease = "alpha")          // 1.0.1-alpha
val nextPreRelease = version.nextPreRelease(preRelease = "alpha")   // 1.0.0-alpha.2

// or with the inc() method:
val incrementedByMajor = version.inc(by = Inc.MAJOR, preRelease = "beta")               // 2.0.0-beta
val incrementedByMinor = version.inc(by = Inc.MINOR, preRelease = "")                   // 1.1.0-0
val incrementedByPatch = version.inc(by = Inc.PATCH, preRelease = "alpha")              // 1.0.1-alpha
val incrementedByPreRelease = version.inc(by = Inc.PRE_RELEASE, preRelease = "alpha")   // 1.0.0-alpha.2

Copy

It's possible to create a copy of a version with its copy() method. It allows altering the copied version's properties with optional parameters.

val version = "1.0.0-alpha.2+build.1".toVersion()

val exactCopy = version.copy()                                            // 1.0.0-alpha.2+build.1
val withDifferentMajor = version.copy(major = 3)                          // 3.0.0-alpha.2+build.1
val withDifferentMinor = version.copy(minor = 4)                          // 1.4.0-alpha.2+build.1
val withDifferentPatch = version.copy(patch = 5)                          // 1.0.5-alpha.2+build.1
val withDifferentPreRelease = version.copy(preRelease = "alpha.4")        // 1.0.0-alpha.4+build.1
val withDifferentBuildMetadata = version.copy(buildMetadata = "build.3")  // 1.0.0-alpha.2+build.3
val withDifferentNumbers = version.copy(major = 3, minor = 4, patch = 5)  // 3.4.5-alpha.2+build.1

Without setting any optional parameter, the copy() method will produce an exact copy of the original version.

Exceptions

When the version parsing fails due to an invalid format, the library throws a specific VersionFormatException. Similarly, when the constraint parsing fails, the library throws a ConstraintFormatException.

The toVersionOrNull() and toConstraintOrNull() methods can be used for exception-less conversions as they return null when the parsing fails.

Contact & Support

• Create an issue for bug reports and feature requests.

• Start a discussion for your questions and ideas.

• Add a ⭐️ to support the project!