scalacenter / Sbt Version Policy
Programming Languages
sbt-version-policy
sbt-version-policy helps library maintainers to follow the recommended versioning scheme. This plugin:
- configures MiMa to check for binary or source incompatibilities,
- ensures that none of your dependencies are bumped or removed in an incompatible way.
Install
Add to your project/plugins.sbt
:
addSbtPlugin("ch.epfl.scala" % "sbt-version-policy" % "<version>")
sbt-version-policy depends on MiMa, so that you don't need to explicitly depend on it.
Configure
The plugin introduces a new key, versionPolicyIntention
, that you need
to set to the level of compatibility that your next release is intended
to provide. It can take the following three values:
-
// Your next release will provide no compatibility guarantees with the // previous one. ThisBuild / versionPolicyIntention := Compatibility.None
-
// Your next release will be binary compatible with the previous one, // but it may not be source compatible. ThisBuild / versionPolicyIntention := Compatibility.BinaryCompatible
-
// Your next release will be both binary compatible and source compatible // with the previous one. ThisBuild / versionPolicyIntention := Compatibility.BinaryAndSourceCompatible
The plugin uses MiMa to check for incompatibilities with the previous
release. The previous release version is automatically computed from
the current value of the version
key in your build. This means that
you have to set this key to the next version you want to release:
// Next version will be 1.1.0
ThisBuild / version := "1.1.0"
In case you use a plugin like sbt-dynver, which automatically sets
the version
based on the Git status, you have nothing to do (the
version
set by sbt-dynver will just work with sbt-version-policy).
Use
Check that pull requests don’t break the intended compatibility level
In your CI server, run the task versionPolicyCheck
on pull requests.
$ sbt versionPolicyCheck
This task checks that the PR does not break the compatibility guarantees
claimed by your versionPolicyIntention
. For instance, if your intention
is to have BinaryAndSourceCompatible
changes, the task
versionPolicyCheck
will fail if the PR breaks binary compatibility
or source compatibility.
Check that release version numbers are valid with respect to the compatibility guarantees they provide
Before you cut a release, run the task versionCheck
.
$ sbt versionCheck
Note: make sure that the version
is set to the new release version
number before you run versionCheck
.
This task checks that the release version number is consistent with the
intended compatibility level as per versionPolicyIntention
. For instance,
if your intention is to publish a release that breaks binary compatibility,
the task versionCheck
will fail if you didn’t bump the major version
number.
versionPolicyCheck
work?
How does The versionPolicyCheck
task:
- checks that there are no binary or source incompatibilities
between the current state of the project and the previous
release (it uses
mimaReportBinaryIssues
under the hood), - and, that no dependencies of your project have been removed
or bumped in an incompatible way (it uses a subtask
versionPolicyReportDependencyIssues
under the hood).
The task versionPolicyCheck
fails if any of these checks fails.
Automatic previous version calculation
sbt-version-policy automatically sets mimaPreviousArtifacts
, depending on the current value of version
, kind of like
sbt-mima-version-check does.
The previously compatible version is computed from version
the following way:
- if it contains "metadata" (anything after a
+
, including the+
itself), drop the metadata part- if the resulting version contains only zeros (like
0.0.0
), leavemimaPreviousArtifacts
empty, - else if the resulting version does not contain a qualifier (see below), it is used in
mimaPreviousArtifacts
. For instance, ifversion
is1.0.0+3-abcd1234
, thenmimaPreviousArtifacts
will contain the artifacts of version1.0.0
.
- if the resulting version contains only zeros (like
- else, drop the qualifier part, that is any suffix like
-RC1
or-M2
or-alpha
or-SNAPSHOT
- if the resulting version ends with
.0.0
, which corresponds to a major version bump like1.0.0
, or2.0.0
,mimaPreviousArtifacts
is left empty, - else, this is a minor or patch version bump, so the last numerical part of this version
is decreased by one, and used in
mimaPreviousArtifacts
. For instance, ifversion
is1.2.0
, thenmimaPreviousArtifacts
will contain the artifacts of version1.1.0
, and ifversion
is1.2.3
, thenmimaPreviousArtifacts
will contain the artifacts of version1.2.2
.
- if the resulting version ends with
You can see the value of the previous version computed by the plugin by inspecting the key
versionPolicyPreviousVersions
.
Source incompatibilities detection
MiMa can only detect binary incompatibilities. To detect source incompatibilities, this plugin uses MiMa in forward mode as an approximation. This is not always correct and may lead to false positives or false negatives. This is a known limitation of the current implementation.
Incompatibilities caused by removed or bumped dependencies
The subtask versionPolicyReportDependencyIssues
checks that you did not remove or
bump your dependencies in an incompatible way. For instance, if your intention for
the next release is to keep binary compatibility, you can only bump your dependencies
to binary compatible versions.
versionPolicyReportDependencyIssues
compares the dependencies of versionPolicyPreviousArtifacts
to the current ones.
By default, versionPolicyPreviousArtifacts
relies on mimaPreviousArtifacts
from sbt-mima, so that only setting / changing mimaPreviousArtifacts
is enough for both sbt-mima and sbt-version-policy.
Dependency compatibility adjustments
Set versionPolicyDependencySchemes
to specify the versioning scheme used by your libraries.
For instance:
versionPolicyDependencySchemes += "org.scala-lang" % "scala-compiler" % "strict"
The following compatibility types are available:
-
early-semver
: assumes the matched modules follow a variant of Semantic Versioning that enforces compatibility within 0.1.z, -
semver-spec
: assumes the matched modules follow semantic versioning, -
pvp
: assumes the matched modules follow package versioning policy (quite common in Scala), -
always
: assumes all versions of the matched modules are compatible with each other, -
strict
: requires exact matches between the wanted and the selected versions of the matched modules.
If no rules for a module are found in versionPolicyDependencySchemes
, versionPolicyDefaultScheme
is used
as a compatibility type. Its default value is VersionCompatibility.PackVer
(package versioning policy).
Acknowledgments
sbt-version-policy is funded by the Scala Center.