✨ Select highest tag when there are sibling tags

README.md

@@ -88,6 +88,17 @@ To use this feature with the Migration Manager [MiMa](https://github.com/lightbe
 mimaPreviousArtifacts := previousStableVersion.value.map(organization.value %% moduleName.value % _).toSet
 ```
 
+#### Multiple tags on the same commit
+
+In case the last know tag has sibling tags that points at the same commit, the highest tag is used.
+For example, for the following tags:
+```
+v1.0.0
+v10.1  // this tag is the highest selected tag
+v2.0.0
+```
+
+
 ## Tag Requirements
 
 In order to be recognized by sbt-dynver, by default tags must begin with the lowercase letter 'v' followed by a digit.

dynver/src/main/scala/sbtdynver/DynVer.scala

@@ -1,14 +1,14 @@
 package sbtdynver
 
 import java.io.File
-import java.util._, regex.Pattern
-
-import scala.PartialFunction
+import java.util._
+import regex.Pattern
 import scala.util._
-
 import scala.sys.process.Process
+import dynver._
+import impl.NoProcessLogger
 
-import dynver._, impl.NoProcessLogger
+import scala.annotation.tailrec
 
 sealed case class GitRef(value: String)
 final  case class GitCommitSuffix(distance: Int, sha: String)
@@ -172,6 +172,43 @@ sealed case class DynVer(wd: Option[File], separator: String, tagPrefix: String)
           }
         else Some(out)
       }
+      .flatMap(selectFromMultipleTags)
+
+  }
+
+  private def selectFromMultipleTags(out: GitDescribeOutput): Option[GitDescribeOutput] = {
+    def exec(cmd: String) = Try(Process(cmd, wd) !! NoProcessLogger).toOption
+
+    // if out.ref is an annotated tag `git tag --list --points-at ${out.ref.value}` returns tags on that tag object
+    // and not tags on the commit object. So we need to find the commit object SHA the ref points to.
+    (for {
+      // find the commit object SHA of the current commit
+      commitHash <- exec(s"git rev-parse ${out.ref.value}^{commit}")
+      // find all the tags that points at the commit object
+      allTags <- exec(s"git tag --list --points-at $commitHash")
+      highestTag <- allTags.split("\n").toList.map(GitRef(_)).filter(_.isTag).sortWith(hybridAlphaNumericSort).lastOption
+    } yield {
+      out.copy(ref = highestTag)
+    }).orElse(Some(out))
+  }
+
+  private def hybridAlphaNumericSort(a: GitRef, b: GitRef): Boolean = {
+    val a1 = a.dropPrefix
+    val b1 = b.dropPrefix
+    @tailrec
+    def loop(a: String, b: String) : Boolean =
+      if(a.isEmpty) true
+      else if (b.isEmpty) false
+      else if (a.head.isDigit && b.head.isDigit) {
+        val (aNum, aRest) = a.span(_.isDigit)
+        val (bNum, bRest) = b.span(_.isDigit)
+        if (aNum.toInt == bNum.toInt) loop(aRest, bRest)
+        else aNum.toInt < bNum.toInt
+      } else if (a.head.isDigit) true
+      else if (b.head.isDigit) false
+      else if (a.head == b.head) loop(a.tail, b.tail)
+      else a.head < b.head
+    loop(a1, b1)
   }
 
   def getGitPreviousStableTag: Option[GitDescribeOutput] = {
@@ -180,9 +217,10 @@ sealed case class DynVer(wd: Option[File], separator: String, tagPrefix: String)
       // as merge commits can have multiple parents
       parentHash <- execAndHandleEmptyOutput("git --no-pager log --pretty=%H -n 1 HEAD^1")
       // Find the closest tag of the parent commit
-      tag <- execAndHandleEmptyOutput(s"git describe --tags --abbrev=0 --match $TagPattern --always $parentHash")
-      out <- PartialFunction.condOpt(tag)(parser.parse)
-    } yield out
+      closestTag <- execAndHandleEmptyOutput(s"git describe --tags --abbrev=0 --match $TagPattern --always $parentHash")
+      outOfClosestTag <- PartialFunction.condOpt(closestTag)(parser.parse)
+      highestTag <- selectFromMultipleTags(outOfClosestTag)
+    } yield highestTag
   }
 
   def timestamp(d: Date): String = GitDescribeOutput.timestamp(d)

dynver/src/test/scala/sbtdynver/DynVerSpec.scala

@@ -14,6 +14,14 @@ object VersionSpec extends Properties("VersionSpec") {
   property("on tag v1.0.0 and 1 commit, w/o local changes") = onTag.commit         .version ?= "1.0.0+1-1234abcd"
   property("on tag v1.0.0 and 1 commit with local changes") = onTag.commit.dirty   .version ?= "1.0.0+1-1234abcd+20160917-0000"
   property("on tag v2")                                     = onTag.commit.tag("2").version ?= "2" // #7, didn't match
+  // for multiple tags, the highest tag is used
+  property("on multiple tags v1.0.0 and v2.0.0, w/o local changes") = onMultipleTags.version ?= "2.0.0"
+  property("on multiple tags v1.0.0 and v2.0.0, with local changes") = onMultipleTags.dirty.version ?= "2.0.0+0-1234abcd+20160917-0000"
+  property("on multiple tags v1.0.0 and v2.0.0, with local changes") = onMultipleTags.dirty.version ?= "2.0.0+0-1234abcd+20160917-0000"
+  property("on multiple tags v1.0.0 and v2.0.0, and 1 commit, w/o local changes") = onMultipleTags.commit.version ?= "2.0.0+1-1234abcd"
+  property("on multiple tags v1.0.0 and v2.0.0, and 1 commit with local changes") = onMultipleTags.commit.dirty.version ?= "2.0.0+1-1234abcd+20160917-0000"
+  property("on multiple tags v1.0.0 and v2.0.0, numerical sort") = onMultipleTags.tag("10.3").tag("10.20").version ?= "10.20" // 1.0.0 < 2.0.0 < 10.1 < 10.20
+  property("on multiple tags v1.0.0 and v2.0.0, then tag v2") = onMultipleTags.commit.tag("2").version ?= "2" // #previous tags didn't match
 }
 
 object PreviousVersionSpec extends Properties("PreviousVersionSpec") {
@@ -27,6 +35,12 @@ object PreviousVersionSpec extends Properties("PreviousVersionSpec") {
   property("on tag v1.0.0 and 1 commit with local changes") = onTag.commit.dirty       .previousVersion ?= Some("1.0.0")
   property("on tag v2.0.0, w/o local changes")              = onTag.commit.tag("2.0.0").previousVersion ?= Some("1.0.0")
 
+  property("on multiple tags v1.0.0 and v2.0.0, w/o local changes") = onMultipleTags.previousVersion ?= None
+  property("on multiple tags v1.0.0 and v2.0.0, with local changes") = onMultipleTags.dirty.previousVersion ?= None
+  property("on multiple tags v1.0.0 and v2.0.0, and 1 commit, w/o local changes") = onMultipleTags.commit.previousVersion ?= Some("2.0.0")
+  property("on multiple tags v1.0.0 and v2.0.0, and 1 commit with local changes") = onMultipleTags.commit.dirty.previousVersion ?= Some("2.0.0")
+  property("on tag v3.0.0 with previous multiple tags v1.0.0 and v2.0.0") = onMultipleTags.commit.tag("3.0.0").previousVersion ?= Some("2.0.0")
+
   property("w/ merge commits")            = onBranch2x.checkout("master").merge("2.x") .previousVersion ?= Some("1.0.0")
   property("w/ merge commits + tag")      = onBranch2Tag                               .previousVersion ?= Some("1.0.0")
   property("on multiple branches")        = onMultiBranch.checkout("2.x")              .previousVersion ?= Some("2.0.0")
@@ -44,12 +58,16 @@ object IsSnapshotSpec extends Properties("IsSnapshotSpec") {
   property("on tag v1.0.0 and 1 commit, w/o local changes") = onTag.commit         .isSnapshot ?= true
   property("on tag v1.0.0 and 1 commit with local changes") = onTag.commit.dirty   .isSnapshot ?= true
   property("on tag v2")                                     = onTag.commit.tag("2").isSnapshot ?= false
+  property("on multiple tags, w/o local changes")           = onMultipleTags.isSnapshot        ?= false
+  property("on multiple tags and 1 commit, w/o local changes") = onMultipleTags.commit.isSnapshot ?= true
+  property("on multiple tags v1.0.0 and 1 commit with local changes") = onMultipleTags.commit.dirty.isSnapshot ?= true
 }
 
 object SonatypeSnapshotSpec extends Properties("SonatypeSnapshotSpec") {
   property("on tag v1.0.0 with local changes")                = onTag.dirty          .sonatypeVersion ?= "1.0.0+0-1234abcd+20160917-0000-SNAPSHOT"
   property("on tag v1.0.0 and 1 commit, w/o local changes S") = onTag.commit         .sonatypeVersion ?= "1.0.0+1-1234abcd-SNAPSHOT"
   property("on tag v1.0.0, w/o local changes")                = onTag                .sonatypeVersion ?= "1.0.0"
+  property("on multiple tags, w/o local changes")             = onMultipleTags       .sonatypeVersion ?= "2.0.0"
   property("on tag v2")                                       = onTag.commit.tag("2").sonatypeVersion ?= "2"
 }
 
@@ -63,4 +81,7 @@ object isVersionStableSpec extends Properties("IsVersionStableSpec") {
   property("on tag v1.0.0 and 1 commit, w/o local changes") = onTag.commit         .isVersionStable ?= true
   property("on tag v1.0.0 and 1 commit with local changes") = onTag.commit.dirty   .isVersionStable ?= false
   property("on tag v2")                                     = onTag.commit.tag("2").isVersionStable ?= true
+  property("on multiple tags, w/o local changes")           = onMultipleTags.isVersionStable        ?= true
+  property("on multiple tags and 1 commit w/o local changes") = onMultipleTags.commit.isVersionStable ?= true
+  property("on multiple tags with local changes")           = onMultipleTags.dirty.isVersionStable  ?= false
 }

dynver/src/test/scala/sbtdynver/RepoStates.scala

@@ -17,6 +17,7 @@ sealed class RepoStates(tagPrefix: String) {
   def noCommits     = notAGitRepo.init
   def onCommit      = noCommits.commit.commit.commit
   def onTag         = onCommit.tag("1.0.0")
+  def onMultipleTags = onTag.tag("2.0.0")
   def onBranch2x    = onTag.branch("2.x").commit
   def onBranch2Tag  = onBranch2x.tag("2.0.0")
   def onMultiBranch = onBranch2Tag.commit.tag("2.1.0").checkout("master").commit.tag("1.1.0")