feat: adding prerelease version increments (#397)

**Background Summary**
This PR adds support for incrementing prerelease versions by default, if it ends in a number. Currently, if a prerelease version is incremented, the prerelease qualifier is simply dropped. E.g. `1.0.0-RC1` will be incremented to `1.0.0`. After this merge, `1.0.0-RC1` will be incremented to `1.0.0-RC2`, but prerelease versions without a version number will behave as before: `1.0.0-alpha` will be incremented to `1.0.0`.

**New/Updated Versioning Strategies**
`Next` (**updated - breaking change**):   Will now increment prerelease versions, unlike in the past. So `1.0-RC1` will become `1.0-RC2`. Previously `1.0-RC1` would become `1.1`.

`NextStable` (**new**): The same as `Next` except that it excludes any prerelease versions. So `1.0.0-RC1` becomes `1.0.0`

.gitignore

@@ -2,3 +2,4 @@ target
 project/target
 .idea
 .idea_modules
+.bsp

README.md

@@ -109,21 +109,31 @@ A cross release behaves analogous to using the `+` command:
 
 In the section *Customizing the release process* we take a look at how to define a `ReleaseStep` to participate in a cross build.
 
-### Convenient versioning
+### Versioning Strategies
 
-As of version 0.8, *sbt-release* comes with some strategies for computing the next snapshot version via the `releaseVersionBump` setting. These strategies are defined in `sbtrelease.Version.Bump`. By default, the `Next` strategy is used:
+As of version 0.8, *sbt-release* comes with several strategies for computing the next snapshot version via the `releaseVersionBump` setting. These strategies are defined in `sbtrelease.Version.Bump`. By default, the `Next` strategy is used:
 
  * `Major`: always bumps the *major* part of the version
  * `Minor`: always bumps the *minor* part of the version
  * `Bugfix`: always bumps the *bugfix* part of the version
  * `Nano`: always bumps the *nano* part of the version
- * `Next`: bumps the last version part (e.g. `0.17` -> `0.18`, `0.11.7` -> `0.11.8`, `3.22.3.4.91` -> `3.22.3.4.92`)
+ * `Next` (**default**): bumps the last version part, including the qualifier (e.g. `0.17` -> `0.18`, `0.11.7` -> `0.11.8`, `3.22.3.4.91` -> `3.22.3.4.92`, `1.0.0-RC1` -> `1.0.0-RC2`)
+ * `NextStable`: bumps exactly like `Next` except that any prerelease qualifier is excluded (e.g. `1.0.0-RC1` -> `1.0.0`)
 
-Example:
+Users can set their preferred versioning strategy in `build.sbt` as follows:
+```sbt
+releaseVersionBump := sbtrelease.Version.Bump.Major
+```
+
+### Default Versioning
+
+The default settings make use of the helper class [`Version`](https://github.com/sbt/sbt-release/blob/master/src/main/scala/Version.scala) that ships with *sbt-release*.
+
+`releaseVersion`: The current version in version.sbt, without the "-SNAPSHOT" ending. So, if `version.sbt` contains `1.0.0-SNAPSHOT`, the release version will be set to `1.0.0`.
 
-    releaseVersionBump := sbtrelease.Version.Bump.Major
+`releaseNextVersion`: The "bumped" version according to the versioning strategy (explained above), including the `-SNAPSHOT` ending. So, if `releaseVersion` is `1.0.0`, `releaseNextVersion` will be `1.0.1-SNAPSHOT`.
 
-### Custom versioning
+### Custom Versioning
 
 *sbt-release* comes with two settings for deriving the release version and the next development version from a given version.
 
@@ -132,20 +142,8 @@ These derived versions are used for the suggestions/defaults in the prompt and f
 Let's take a look at the types:
 
 ```scala
-val releaseVersion     : SettingKey[String => String]
-val releaseNextVersion : SettingKey[String => String]
-```
-
-The default settings make use of the helper class [`Version`](https://github.com/sbt/sbt-release/blob/master/src/main/scala/Version.scala) that ships with *sbt-release*.
-
-```scala
-// strip the qualifier off the input version, eg. 1.2.1-SNAPSHOT -> 1.2.1
-releaseVersion     := { ver => Version(ver).map(_.withoutQualifier.string).getOrElse(versionFormatError(ver)) }
-
-// bump the version and append '-SNAPSHOT', eg. 1.2.1 -> 1.3.0-SNAPSHOT
-releaseNextVersion := {
-  ver => Version(ver).map(_.bump(releaseVersionBump.value).asSnapshot.string).getOrElse(versionFormatError(ver))
-},
+val releaseVersion     : TaskKey[String => String]
+val releaseNextVersion : TaskKey[String => String]
 ```
 
 If you want to customize the versioning, keep the following in mind:

src/main/scala/ReleasePlugin.scala

@@ -1,11 +1,11 @@
 package sbtrelease
 
 import java.io.Serializable
-
-import sbt._
-import Keys._
-import sbt.complete.DefaultParsers._
+import sbt.*
+import Keys.*
+import sbt.complete.DefaultParsers.*
 import sbt.complete.Parser
+import sbtrelease.Version.Bump
 
 object ReleasePlugin extends AutoPlugin {
 
@@ -73,7 +73,7 @@ object ReleasePlugin extends AutoPlugin {
       withStreams(extracted.structure, st) { str =>
         val nv = nodeView(st, str, key :: Nil)
         val (newS, result) = runTask(task, st, str, extracted.structure.index.triggers, config)(nv)
-        (newS, processResult(result, newS.log))
+        (newS, processResult2(result))
       }._1
     }
 
@@ -222,11 +222,23 @@ object ReleasePlugin extends AutoPlugin {
       val snapshots = moduleIds.filter(m => m.isChanging || m.revision.endsWith("-SNAPSHOT"))
       snapshots
     },
-
-    releaseVersion := { ver => Version(ver).map(_.withoutQualifier.string).getOrElse(versionFormatError(ver)) },
+    releaseVersion := { rawVersion =>
+      Version(rawVersion).map { version =>
+        releaseVersionBump.value match {
+          case Bump.Next =>
+            if (version.isSnapshot) {
+              version.withoutSnapshot.unapply
+            } else {
+              expectedSnapshotVersionError(rawVersion)
+            }
+          case _ => version.withoutQualifier.unapply
+        }
+      }
+      .getOrElse(versionFormatError(rawVersion))
+    },
     releaseVersionBump := Version.Bump.default,
     releaseNextVersion := {
-      ver => Version(ver).map(_.bump(releaseVersionBump.value).asSnapshot.string).getOrElse(versionFormatError(ver))
+      ver => Version(ver).map(_.bump(releaseVersionBump.value).asSnapshot.unapply).getOrElse(versionFormatError(ver))
     },
     releaseUseGlobalVersion := true,
     releaseCrossBuild := false,

src/main/scala/Version.scala

@@ -1,24 +1,62 @@
 package sbtrelease
 
-import util.control.Exception._
+import scala.util.matching.Regex
+import util.control.Exception.*
 
 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
+    /**
+     * Strategy to always bump the major version by default. Ex. 1.0.0 would be bumped to 2.0.0
+     */
+    case object Major extends Bump { def bump: Version => Version = _.bumpMajor }
+    /**
+     * Strategy to always bump the minor version by default. Ex. 1.0.0 would be bumped to 1.1.0
+     */
+    case object Minor extends Bump { def bump: Version => Version = _.bumpMinor }
+    /**
+     * Strategy to always bump the bugfix version by default. Ex. 1.0.0 would be bumped to 1.0.1
+     */
+    case object Bugfix extends Bump { def bump: Version => Version = _.bumpBugfix }
+    /**
+     * Strategy to always bump the nano version by default. Ex. 1.0.0.0 would be bumped to 1.0.0.1
+     */
+    case object Nano extends Bump { def bump: Version => Version = _.bumpNano }
+
+
+    /**
+     * Strategy to always increment to the next version from smallest to greatest, including prerelease versions
+     * Ex:
+     * Major: 1 becomes 2
+     * Minor: 1.0 becomes 1.1
+     * Bugfix: 1.0.0 becomes 1.0.1
+     * Nano: 1.0.0.0 becomes 1.0.0.1
+     * Qualifier with version number: 1.0-RC1 becomes 1.0-RC2
+     * Qualifier without version number: 1.0-alpha becomes 1.0
+     */
+    case object Next extends Bump { def bump: Version => Version = _.bumpNext }
+
+    /**
+     * Strategy to always increment to the next version from smallest to greatest, excluding prerelease versions
+     * Ex:
+     * Major: 1 becomes 2
+     * Minor: 1.0 becomes 1.1
+     * Bugfix: 1.0.0 becomes 1.0.1
+     * Nano: 1.0.0.0 becomes 1.0.0.1
+     * Qualifier with version number: 1.0-RC1 becomes 1.0
+     * Qualifier without version number: 1.0-alpha becomes 1.0
+     */
+    case object NextStable extends Bump { def bump: Version => Version = _.bumpNextStable }
+
+    val default: Bump = Next
   }
 
-  val VersionR = """([0-9]+)((?:\.[0-9]+)+)?([\.\-0-9a-zA-Z]*)?""".r
-  val PreReleaseQualifierR = """[\.-](?i:rc|m|alpha|beta)[\.-]?[0-9]*""".r
+  val VersionR: Regex = """([0-9]+)((?:\.[0-9]+)+)?([\.\-0-9a-zA-Z]*)?""".r
+  val PreReleaseQualifierR: Regex = """[\.-](?i:rc|m|alpha|beta)[\.-]?[0-9]*""".r
 
   def apply(s: String): Option[Version] = {
     allCatch opt {
@@ -34,24 +72,52 @@ object Version {
 }
 
 case class Version(major: Int, subversions: Seq[Int], qualifier: Option[String]) {
-  def bump = {
-    val maybeBumpedPrerelease = qualifier.collect {
-      case Version.PreReleaseQualifierR() => withoutQualifier
+
+  @deprecated("Use .bumpNext or .bumpNextStable instead")
+  def bump: Version = bumpNext
+
+  def bumpNext: Version = {
+    val bumpedPrereleaseVersionOpt = qualifier.collect {
+      case rawQualifier @ Version.PreReleaseQualifierR() =>
+        val qualifierEndsWithNumberRegex = """[0-9]*$""".r
+
+        val opt = for {
+          versionNumberQualifierStr <- qualifierEndsWithNumberRegex.findFirstIn(rawQualifier)
+          versionNumber <- Try(versionNumberQualifierStr.toInt)
+            .toRight(new Exception(s"Version number not parseable to a number. Version number received: $versionNumberQualifierStr"))
+            .toOption
+          newVersionNumber = versionNumber + 1
+          newQualifier = rawQualifier.replaceFirst(versionNumberQualifierStr, newVersionNumber.toString)
+        } yield Version(major, subversions, Some(newQualifier))
+
+        opt.getOrElse(this.withoutQualifier)
     }
-    def maybeBumpedLastSubversion = bumpSubversionOpt(subversions.length-1)
+
+    bumpNextGeneric(bumpedPrereleaseVersionOpt)
+  }
+  private def bumpNextGeneric(bumpedPrereleaseVersionOpt: Option[Version]): Version = {
+    def maybeBumpedLastSubversion = bumpSubversionOpt(subversions.length - 1)
+
     def bumpedMajor = copy(major = major + 1)
 
-    maybeBumpedPrerelease
+    bumpedPrereleaseVersionOpt
       .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 bumpNextStable: Version = {
+    val bumpedPrereleaseVersionOpt = qualifier.collect {
+      case Version.PreReleaseQualifierR() => withoutQualifier
+    }
+    bumpNextGeneric(bumpedPrereleaseVersionOpt)
+  }
+
+  def bumpMajor: Version = copy(major = major + 1, subversions = Seq.fill(subversions.length)(0))
+  def bumpMinor: Version = maybeBumpSubversion(0)
+  def bumpBugfix: Version = maybeBumpSubversion(1)
+  def bumpNano: Version = maybeBumpSubversion(2)
 
-  def maybeBumpSubversion(idx: Int) = bumpSubversionOpt(idx) getOrElse this
+  def maybeBumpSubversion(idx: Int): Version = bumpSubversionOpt(idx) getOrElse this
 
   private def bumpSubversionOpt(idx: Int) = {
     val bumped = subversions.drop(idx)
@@ -64,10 +130,30 @@ case class Version(major: Int, subversions: Seq[Int], qualifier: Option[String])
 
   def bump(bumpType: Version.Bump): Version = bumpType.bump(this)
 
-  def withoutQualifier = copy(qualifier = None)
-  def asSnapshot = copy(qualifier = Some("-SNAPSHOT"))
+  def withoutQualifier: Version = copy(qualifier = None)
+  def asSnapshot: Version = copy(qualifier = qualifier.map { qualifierStr =>
+    s"$qualifierStr-SNAPSHOT"
+  }.orElse(Some("-SNAPSHOT")))
+
+  def isSnapshot: Boolean = qualifier.exists { qualifierStr =>
+    val snapshotRegex = """(^.*)-SNAPSHOT$""".r
+    qualifierStr.matches(snapshotRegex.regex)
+  }
+
+  def withoutSnapshot: Version = copy(qualifier = qualifier.flatMap { qualifierStr =>
+    val snapshotRegex = """-SNAPSHOT""".r
+    val newQualifier = snapshotRegex.replaceFirstIn(qualifierStr, "")
+    if (newQualifier == qualifierStr) {
+      None
+    } else {
+      Some(newQualifier)
+    }
+  })
+
+  @deprecated("Use .unapply instead")
+  def string: String = unapply
 
-  def string = "" + major + mkString(subversions) + qualifier.getOrElse("")
+  def unapply: String = "" + major + mkString(subversions) + qualifier.getOrElse("")
 
   private def mkString(parts: Seq[Int]) = parts.map("."+_).mkString
 }

src/main/scala/package.scala

@@ -2,4 +2,6 @@ package object sbtrelease {
   type Versions = (String, String)
 
   def versionFormatError(version: String) = sys.error(s"Version [$version] format is not compatible with " + Version.VersionR.pattern.toString)
+
+  def expectedSnapshotVersionError(version: String) = sys.error(s"Expected snapshot version. Received: $version")
 }

src/sbt-test/sbt-release/with-defaults/build.sbt

@@ -1,3 +1,4 @@
+import sbt.complete.DefaultParsers._
 import sbtrelease.ReleaseStateTransformations._
 
 releaseVersionFile := file("version.sbt")
@@ -13,3 +14,12 @@ releaseProcess := Seq(
   setNextVersion,
   commitNextVersion
 )
+
+val checkContentsOfVersionSbt = inputKey[Unit]("Check that the contents of version.sbt is as expected")
+val parser = Space ~> StringBasic
+
+checkContentsOfVersionSbt := {
+  val expected = parser.parsed
+  val versionFile = ((baseDirectory).value) / "version.sbt"
+  assert(IO.read(versionFile).contains(expected), s"does not contains ${expected} in ${versionFile}")
+}

src/sbt-test/sbt-release/with-defaults/test

@@ -1,11 +1,41 @@
-$ exec git init .
+# Test Suite Preparation
+    $ exec git init .
+    > update
+    $ exec git add .
+    $ exec git commit -m init
+    > reload
 
-> update
+# SCENARIO: When no release versions are specified in the release command
+    # TEST: Should fail to release if "with-defaults" is not specified
+        -> release
 
-$ exec git add .
-$ exec git commit -m init
+    # TEST: Should succeed if "with-defaults" is specified
+        > release with-defaults
 
-> reload
+# SCENARIO: When default bumping strategy is used
+    # Test Scenario Preparation
+        > 'release release-version 0.9.9 next-version 1.0.0-RC1-SNAPSHOT'
+        > reload
+        > checkContentsOfVersionSbt 1.0.0-RC1-SNAPSHOT
+
+    # TEST: Snapshot version should be correctly set
+        > release with-defaults
+        > checkContentsOfVersionSbt 1.0.0-RC2-SNAPSHOT
+
+    # TEST: Release version should be correctly set
+        $ exec git reset --hard HEAD~1
+        > reload
+        > checkContentsOfVersionSbt 1.0.0-RC1
+
+# SCENARIO: When NextStable bumping strategy is used
+    # TEST: Snapshot version should be correctly set
+        $ exec git reset --hard HEAD~1
+        > set releaseVersionBump := sbtrelease.Version.Bump.NextStable
+        > release with-defaults
+        > checkContentsOfVersionSbt 1.0.1-SNAPSHOT
+
+    # TEST: Release version should be correctly set
+        $ exec git reset --hard HEAD~1
+        > reload
+        > checkContentsOfVersionSbt 1.0.0
 
--> release
-> release with-defaults