Simplify integration with sbt-release

README.md

@@ -211,24 +211,12 @@ In this mode, you can use sbt-version-policy to check that incoming pull request
 - compute the next release version according to its compatibility guarantees
     1. set the key `releaseVersion` as follows:
        ~~~ scala
-       releaseVersion := {
-         val maybeBump = versionPolicyIntention.value match {
-            case Compatibility.None                      => Some(Version.Bump.Major)
-            case Compatibility.BinaryCompatible          => Some(Version.Bump.Minor)
-            case Compatibility.BinaryAndSourceCompatible => None // No need to bump the patch version, because it has already been bumped when sbt-release set the next release version
-          }
-          { (currentVersion: String) =>
-            val versionWithoutQualifier =
-              Version(currentVersion)
-                .getOrElse(versionFormatError(currentVersion))
-                .withoutQualifier
-            (maybeBump match {
-              case Some(bump) => versionWithoutQualifier.bump(bump)
-              case None       => versionWithoutQualifier
-            }).string
-          }
-       }
+       import sbtversionpolicy.withsbtrelease.ReleaseVersion
+       releaseVersion := ReleaseVersion.fromCompatibility(versionPolicyIntention.value)
        ~~~
+       The `releaseVersion` function bumps the release version according to the compatibility guarantees defined
+       by `versionPolicyIntention`. Optionally, you can also define a _qualifier_ to append to the release version
+       by setting the environment variable `VERSION_POLICY_RELEASE_QUALIFIER` (e.g., `VERSION_POLICY_RELEASE_QUALIFIER=RC1`).
     2. Reset `versionPolicyIntention` to `Compatibility.BinaryAndSourceCompatible` after every release.
        This can be achieved by managing the setting `versionPolicyIntention` in a separate file (like [sbt-release] manages the setting `version` in a separate file, by default), and by adding a step that overwrites the content of that file and commits it.
 
@@ -237,34 +225,40 @@ In this mode, you can use sbt-version-policy to check that incoming pull request
 You can have a look at the test [example-sbt-release](./sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-release)
 for an example of sbt project using both sbt-version-policy and sbt-release.
 
+In that example, we also automatically reset the intended compatibility level to `BinaryAndSourceCompatible` as the last step of the release process.
+
 #### Unconstrained compatibility level
 
 In this mode, you can use sbt-version-policy to assess the incompatibilities introduced in the project since the last release and compute the new release version accordingly (ie, to bump the major version number if you introduced binary incompatibilities):
 
 1. make sure `versionPolicyIntention` is not set
-2. define `releaseVersion` from the compatibility level returned by `versionPolicyAssessCompatibility`
+2. define `releaseVersion` from the compatibility level returned by `versionPolicyAssessCompatibility`:
+   ~~~ scala
+   import sbtversionpolicy.withsbtrelease.ReleaseVersion
+
+   releaseVersion := {
+     ReleaseVersion.fromAssessedCompatibilityWithLatestRelease().value
+   }
+   ~~~
+   Alternatively, if your project contains multiple modules, you want to use the aggregated assessed compatibility level:
    ~~~ scala
+   import sbtversionpolicy.withsbtrelease.ReleaseVersion
+
    releaseVersion := {
-     val compatibilityWithPreviousReleases = versionPolicyAssessCompatibility.value
-     val compatibilityWithLastRelease = compatibilityWithPreviousReleases.head
-     val (_, compatibility) = compatibilityWithLastRelease
-     val maybeBump = compatibility match {
-        case Compatibility.None                      => Some(Version.Bump.Major)
-        case Compatibility.BinaryCompatible          => Some(Version.Bump.Minor)
-        case Compatibility.BinaryAndSourceCompatible => None // No need to bump the patch version, because it has already been bumped when sbt-release set the next release version
-      }
-      { (currentVersion: String) =>
-        val versionWithoutQualifier =
-          Version(currentVersion)
-            .getOrElse(versionFormatError(currentVersion))
-            .withoutQualifier
-        (maybeBump match {
-          case Some(bump) => versionWithoutQualifier.bump(bump)
-          case None       => versionWithoutQualifier
-        }).string
-      }
+     ReleaseVersion.fromAggregatedAssessedCompatibilityWithLatestRelease().value
    }
    ~~~
+   In both cases, the `releaseVersion` function sets the release version according to the compatibility level
+   with the latest release. Optionally, you can also define a _qualifier_ to append to the release version
+   by setting the environment variable `VERSION_POLICY_RELEASE_QUALIFIER` (e.g., `VERSION_POLICY_RELEASE_QUALIFIER="-RC1"`).
+
+Note that for the first release you have to set the release version yourself via the file `version.sbt` (e.g., set
+`1.0.0-SNAPSHOT` or `0.1.0-SNAPSHOT`). This is because `sbt-version-policy` needs a previous release to exist to be
+able to assess the compatibility level of the current state of the project with that release.
+
+##### Example
+
+We demonstrate the “unconstrained” mode in [this example](./sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-release-unconstrained).
 
 ## How does `versionPolicyCheck` work?
 

sbt-version-policy/src/main/scala/sbtversionpolicy/withsbtrelease/ReleaseVersion.scala

@@ -0,0 +1,123 @@
+package sbtversionpolicy.withsbtrelease
+
+import sbtversionpolicy.Compatibility
+import sbtversionpolicy.SbtVersionPolicyPlugin.aggregatedAssessedCompatibilityWithLatestRelease
+import sbtversionpolicy.SbtVersionPolicyPlugin.autoImport.versionPolicyAssessCompatibility
+import sbt.*
+import sbtversionpolicy.SbtVersionPolicyMima.autoImport.versionPolicyPreviousVersions
+
+/** Convenient methods to integrate with the plugin sbt-release */
+object ReleaseVersion {
+
+  private val qualifierVariableName = "VERSION_POLICY_RELEASE_QUALIFIER"
+
+  /**
+   * @return a [release version function](https://github.com/sbt/sbt-release?tab=readme-ov-file#custom-versioning)
+   *         that bumps the patch, minor, or major version number depending on the provided
+   *         compatibility level.
+   * @param qualifier Optional qualifier to append to the version (e.g. `"-RC1"`). By default, it tries to read
+   *                  it from the environment variable VERSION_POLICY_RELEASE_QUALIFIER.
+   */
+  def fromCompatibility(compatibility: Compatibility, qualifier: String = sys.env.getOrElse(qualifierVariableName, "")): String => String = {
+    val maybeBump =
+      compatibility match {
+        case Compatibility.None => Some(Version.Bump.Major)
+        case Compatibility.BinaryCompatible => Some(Version.Bump.Minor)
+        case Compatibility.BinaryAndSourceCompatible => None // No need to bump the patch version, because it has already been bumped when sbt-release set the next release version
+      }
+    { (currentVersion: String) =>
+      val versionWithoutQualifier =
+        Version(currentVersion)
+          .getOrElse(Version.formatError(currentVersion))
+          .withoutQualifier
+      val bumpedVersion =
+        (maybeBump match {
+          case Some(bump) => versionWithoutQualifier.bump(bump)
+          case None => versionWithoutQualifier
+        }).string
+      bumpedVersion + qualifier
+    }
+  }
+
+  private def fromAssessedCompatibility(qualifier: String)(assessCompatibility: Def.Initialize[Task[Compatibility]]): Def.Initialize[Task[String => String]] =
+    Def.ifS(Def.task {
+      versionPolicyPreviousVersions.value.isEmpty
+    })(Def.task {
+      // If there are no previous versions to assess the compatibility with,
+      // fallback to the default release version function, which drops the qualifier
+      // from the version set in the file `version.sbt`
+      // (e.g., "1.0.0-SNAPSHOT" => "1.0.0")
+      (version: String) =>
+        Version(version)
+          .map(_.withoutQualifier.string + qualifier)
+          .getOrElse(Version.formatError(version))
+    })(Def.task {
+      val log = Keys.streams.value.log
+      val compatibility = assessCompatibility.value
+      log.debug(s"Compatibility level is ${compatibility}")
+      fromCompatibility(compatibility, qualifier)
+    })
+
+  /**
+   * Task returning a [release version function](https://github.com/sbt/sbt-release?tab=readme-ov-file#custom-versioning)
+   * based on the assessed compatibility level of the project.
+   *
+   * Use it in your `.sbt` build definition as follows:
+   *
+   * {{{
+   *   import sbtversionpolicy.withsbtrelease.ReleaseVersion
+   *
+   *   releaseVersion := ReleaseVersion.fromAssessedCompatibilityWithLatestRelease().value
+   * }}}
+   *
+   * sbt-release uses the `releaseVersion` function to set the version before publishing a release (at step
+   * `setReleaseVersion`). It reads the current `version` (usually defined in a file `version.sbt`, and looking
+   * like `"1.2.3-SNAPSHOT"`), and applies the function to it.
+   *
+   * @param qualifier Optional qualifier to append to the version (e.g. `"-RC1"`). By default, it tries to read
+   *                  it from the environment variable VERSION_POLICY_RELEASE_QUALIFIER.
+   */
+  def fromAssessedCompatibilityWithLatestRelease(
+    qualifier: String = sys.env.getOrElse(qualifierVariableName, "")
+  ): Def.Initialize[Task[String => String]] =
+    fromAssessedCompatibility(qualifier)(Def.task {
+      val compatibilityResults = versionPolicyAssessCompatibility.value
+      val compatibilityWithLatestRelease =
+        compatibilityResults.headOption
+          .getOrElse(throw new MessageOnlyException("Unable to assess the compatibility level of this project."))
+      val (_, compatibility) = compatibilityWithLatestRelease
+      compatibility
+    })
+
+  /**
+   * Task returning a [release version function](https://github.com/sbt/sbt-release?tab=readme-ov-file#custom-versioning)
+   * based on the assessed compatibility level of the project (ie, the highest level of compatibility
+   * satisfied by all the sub-projects aggregated by this project).
+   *
+   * Use it in the root project of your `.sbt` build definition as follows:
+   *
+   * {{{
+   *   import sbtversionpolicy.withsbtrelease.ReleaseVersion
+   *
+   *   val `my-project` =
+   *     project
+   *       .in(file("."))
+   *       .aggregate(mySubproject1, mySubproject2)
+   *       .settings(
+   *         releaseVersion := ReleaseVersion.fromAggregatedAssessedCompatibilityWithLatestRelease().value
+   *       )
+   * }}}
+   *
+   * sbt-release uses the `releaseVersion` function to set the version before publishing a release (at step
+   * `setReleaseVersion`). It reads the current `version` (usually defined in a file `version.sbt`, and looking
+   * like `"1.2.3-SNAPSHOT"`), and applies the function to it.
+   *
+   * @param qualifier Optional qualifier to append to the version (e.g. `"-RC1"`). By default, it tries to read
+   *                  it from the environment variable VERSION_POLICY_RELEASE_QUALIFIER.
+   */
+  def fromAggregatedAssessedCompatibilityWithLatestRelease(
+    qualifier: String = sys.env.getOrElse(qualifierVariableName, "")
+  ): Def.Initialize[Task[String => String]] =
+    fromAssessedCompatibility(qualifier)(aggregatedAssessedCompatibilityWithLatestRelease)
+
+}

sbt-version-policy/src/main/scala/sbtversionpolicy/withsbtrelease/Version.scala

@@ -0,0 +1,77 @@
+package sbtversionpolicy.withsbtrelease
+
+// All the code below has been copied from https://github.com/sbt/sbt-release/blob/master/src/main/scala/Version.scala
+
+import util.control.Exception._
+
+private[withsbtrelease] object Version {
+  sealed trait Bump {
+    def bump: Version => Version
+  }
+
+  object Bump {
+    case object Major extends Bump { def bump = _.bumpMajor }
+    case object Minor extends Bump { def bump = _.bumpMinor }
+    case object Bugfix extends Bump { def bump = _.bumpBugfix }
+    case object Nano extends Bump { def bump = _.bumpNano }
+    case object Next extends Bump { def bump = _.bump }
+
+    val default = Next
+  }
+
+  val VersionR = """([0-9]+)((?:\.[0-9]+)+)?([\.\-0-9a-zA-Z]*)?""".r
+  val PreReleaseQualifierR = """[\.-](?i:rc|m|alpha|beta)[\.-]?[0-9]*""".r
+
+  def apply(s: String): Option[Version] = {
+    allCatch opt {
+      val VersionR(maj, subs, qual) = s
+      // parse the subversions (if any) to a Seq[Int]
+      val subSeq: Seq[Int] = Option(subs) map { str =>
+        // split on . and remove empty strings
+        str.split('.').filterNot(_.trim.isEmpty).map(_.toInt).toSeq
+      } getOrElse Nil
+      Version(maj.toInt, subSeq, Option(qual).filterNot(_.isEmpty))
+    }
+  }
+
+  def formatError(version: String) = sys.error(s"Version [$version] format is not compatible with " + Version.VersionR.pattern.toString)
+}
+
+private[withsbtrelease] case class Version(major: Int, subversions: Seq[Int], qualifier: Option[String]) {
+  def bump = {
+    val maybeBumpedPrerelease = qualifier.collect {
+      case Version.PreReleaseQualifierR() => withoutQualifier
+    }
+    def maybeBumpedLastSubversion = bumpSubversionOpt(subversions.length-1)
+    def bumpedMajor = copy(major = major + 1)
+
+    maybeBumpedPrerelease
+      .orElse(maybeBumpedLastSubversion)
+      .getOrElse(bumpedMajor)
+  }
+
+  def bumpMajor  = copy(major = major + 1, subversions = Seq.fill(subversions.length)(0))
+  def bumpMinor  = maybeBumpSubversion(0)
+  def bumpBugfix = maybeBumpSubversion(1)
+  def bumpNano   = maybeBumpSubversion(2)
+
+  def maybeBumpSubversion(idx: Int) = bumpSubversionOpt(idx) getOrElse this
+
+  private def bumpSubversionOpt(idx: Int) = {
+    val bumped = subversions.drop(idx)
+    val reset = bumped.drop(1).length
+    bumped.headOption map { head =>
+      val patch = (head+1) +: Seq.fill(reset)(0)
+      copy(subversions = subversions.patch(idx, patch, patch.length))
+    }
+  }
+
+  def bump(bumpType: Version.Bump): Version = bumpType.bump(this)
+
+  def withoutQualifier = copy(qualifier = None)
+  def asSnapshot = copy(qualifier = Some("-SNAPSHOT"))
+
+  def string = "" + major + mkString(subversions) + qualifier.getOrElse("")
+
+  private def mkString(parts: Seq[Int]) = parts.map("."+_).mkString
+}

sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-release-unconstrained/.gitignore

@@ -0,0 +1,3 @@
+target/
+.bsp/
+global/

sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-release-unconstrained/build.sbt

@@ -0,0 +1,56 @@
+import sbtversionpolicy.withsbtrelease.ReleaseVersion
+import sbtrelease._
+import ReleaseTransformations._
+
+inThisBuild(List(
+  organization := "org.organization",
+  homepage := Some(url("https://github.com/organization/project")),
+  licenses := List("Apache-2.0" -> url("http://www.apache.org/licenses/LICENSE-2.0")),
+  developers := List(
+    Developer(
+      "julienrf",
+      "Julien Richard-Foy",
+      "julien@organization.org",
+      url("https://github.com/julienrf")
+    )
+  ),
+  scalaVersion := "3.0.1"
+))
+
+val module =
+  project
+    .settings(
+      name := "sbt-release-unconstrained-test"
+    )
+
+val root = project.in(file("."))
+  .aggregate(module)
+  .settings(
+    // Tell sbt-release to set the release version based on the level of compatibility with the previous release
+    releaseVersion := ReleaseVersion.fromAggregatedAssessedCompatibilityWithLatestRelease().value,
+    // Custom release process for testing purpose only: the artifacts are locally published,
+    // and we don’t push to the remote repository.
+    releaseProcess := Seq[ReleaseStep](
+      checkSnapshotDependencies,
+      inquireVersions,
+      runClean,
+      runTest,
+      setReleaseVersion,
+      commitReleaseVersion,
+      tagRelease,
+      releaseStepTask(module / publishLocal), // Publish locally for our tests only, in practice you will publish to Sonatype
+      setNextVersion,
+      commitNextVersion,
+      // pushChanges // Disable pushing the changes to the remote repository for our tests only
+    )
+  )
+
+TaskKey[Unit]("checkTag_1_0_0") := {
+  import scala.sys.process._
+  assert("git describe --tags".lineStream.exists(_.contains("v1.0.0")))
+}
+
+TaskKey[Unit]("checkTag_1_1_0") := {
+  import scala.sys.process._
+  assert("git describe --tags".lineStream.exists(_.contains("v1.1.0")))
+}

sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-release-unconstrained/file-to-add.template

@@ -0,0 +1,3 @@
+package org.organization.module
+
+class NewAPI

sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-release-unconstrained/module/src/main/scala/org/organization/module/Dummy.scala

@@ -0,0 +1,3 @@
+package org.organization.module
+
+class Dummy

sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-release-unconstrained/project/plugins.sbt

@@ -0,0 +1,2 @@
+addSbtPlugin("ch.epfl.scala" % "sbt-version-policy" % sys.props("plugin.version"))
+addSbtPlugin("com.github.sbt" % "sbt-release" % "1.1.0")

sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-release-unconstrained/test

@@ -0,0 +1,23 @@
+# Setup repository
+$ exec git init
+$ exec git config user.email "email"
+$ exec git config user.name "name"
+
+$ exec git add .
+$ exec git commit -m "Initial commit"
+> reload
+
+# First release
+> release with-defaults
+> checkTag_1_0_0
+> reload
+
+# New contributions
+$ copy-file file-to-add.template module/src/main/scala/org/organization/module/NewAPI.scala
+$ exec git add module/src/main/scala/org/organization/module/NewAPI.scala
+$ exec git commit -m "Some hard work"
+
+# Second release
+> release with-defaults
+# Check that sbt-version-policy bumped the minor version
+> checkTag_1_1_0

sbt-version-policy/src/sbt-test/sbt-version-policy/example-sbt-release-unconstrained/version.sbt

@@ -0,0 +1 @@
+ThisBuild / version := "1.0.0-SNAPSHOT"