More flexible Scala version switch

By using SemanticSelector instead of custom globbing.

Follow-up on https://github.com/sbt/sbt/pull/6894,
fixes https://github.com/sbt/sbt/issues/6934

main/src/main/scala/sbt/Cross.scala

@@ -8,7 +8,6 @@
 package sbt
 
 import java.io.File
-import java.util.regex.Pattern
 import sbt.Def.{ ScopedKey, Setting }
 import sbt.Keys._
 import sbt.SlashSyntax0._
@@ -19,7 +18,7 @@ import sbt.internal.util.AttributeKey
 import sbt.internal.util.complete.DefaultParsers._
 import sbt.internal.util.complete.{ DefaultParsers, Parser }
 import sbt.io.IO
-import sbt.librarymanagement.CrossVersion
+import sbt.librarymanagement.{ CrossVersion, SemanticSelector, VersionNumber }
 
 /**
  * Cross implements the Scala cross building commands:
@@ -327,10 +326,11 @@ object Cross {
         } ++ structure.units.keys
           .map(BuildRef.apply)
           .map(proj => (proj, Some(version), crossVersions(extracted, proj)))
-      } else if (version.contains('*')) {
+      } else if (isSelector(version)) {
+        val selector = SemanticSelector(version)
         projectScalaVersions.map {
           case (project, scalaVersions) =>
-            globFilter(version, scalaVersions) match {
+            scalaVersions.filter(v => selector.matches(VersionNumber(v))) match {
               case Nil          => (project, None, scalaVersions)
               case Seq(version) => (project, Some(version), scalaVersions)
               case multiple =>
@@ -370,19 +370,13 @@ object Cross {
     (setScalaVersionsForProjects(instance, included, state, extracted), included.map(_._1))
   }
 
-  def globFilter(pattern: String, candidates: Seq[String]): Seq[String] = {
+  // determine whether this is a 'specific' version or a selector
-    def createGlobRegex(remainingPattern: String): String =
+  // to be passed to SemanticSelector
-      remainingPattern.indexOf("*") match {
+  private def isSelector(version: String): Boolean =
-        case -1 => Pattern.quote(remainingPattern)
+    version.contains('*') || version.contains('x') || version.contains('X') || version.contains(' ') ||
-        case n =>
+      version.contains('<') || version.contains('>') || version.contains('|') || version.contains(
-          val chunk = Pattern.quote(remainingPattern.substring(0, n)) + ".*"
+      '='
-          if (remainingPattern.length > n)
+    )
-            chunk + createGlobRegex(remainingPattern.substring(n + 1))
-          else chunk
-      }
-    val compiledPattern = Pattern.compile(createGlobRegex(pattern))
-    candidates.filter(compiledPattern.matcher(_).matches())
-  }
 
   private def setScalaVersionsForProjects(
       instance: Option[(File, ScalaInstance)],

main/src/test/scala/sbt/CrossSpec.scala

@@ -1,20 +0,0 @@
-/*
- * sbt
- * Copyright 2011 - 2018, Lightbend, Inc.
- * Copyright 2008 - 2010, Mark Harrah
- * Licensed under Apache License 2.0 (see LICENSE)
- */
-
-package sbt
-
-object CrossSpec extends verify.BasicTestSuite {
-  import Cross._
-
-  test("glob filter should work as expected") {
-    assert(globFilter("2.13.*", Seq("2.12.8", "2.13.16", "3.0.1")) == Seq("2.13.16"))
-    assert(globFilter("3.*", Seq("2.12.8", "2.13.16", "3.0.1")) == Seq("3.0.1"))
-    assert(globFilter("3.*", Seq("3.0.1", "30.1")) == Seq("3.0.1"))
-    assert(globFilter("2.*", Seq("2.12.8", "2.13.16", "3.0.1")) == Seq("2.12.8", "2.13.16"))
-    assert(globFilter("4.*", Seq("2.12.8", "2.13.16", "3.0.1")) == Nil)
-  }
-}

sbt-app/src/sbt-test/actions/cross-multiproject/test

@@ -52,7 +52,7 @@ $ exists sbt-foo/target/scala-2.12
 
 # test wildcard switching (2.13)
 > clean
-> ++ 2.13.* -v compile
+> ++ 2.13.x -v compile
 $ exists lib/target/scala-2.13
 -$ exists lib/target/scala-2.12
 # -$ exists sbt-foo/target/scala-2.12