SI-9167 Clarify ScalaVersion parsing

Probably it was unintended to accept "2.." and "2.-11.7".

This commit makes it a bit more regular and also accepts arbitrary
text after the dash in the build string, including newlines.

Since the number parts must be numbers, accept only digits.
That also disallows "2.+11.7", which could be misconstrued as
some sort of range.

As before, the special build string prefixes "rc" and "m" are
case-insensitive, but "FINAL" is not.

1 files changed, 22 insertions, 28 deletions

diff --git a/src/compiler/scala/tools/nsc/settings/ScalaVersion.scala b/src/compiler/scala/tools/nsc/settings/ScalaVersion.scala
index 43bdad5882..7e67b7bec6 100644
--- a/src/compiler/scala/tools/nsc/settings/ScalaVersion.scala
+++ b/src/compiler/scala/tools/nsc/settings/ScalaVersion.scala
@@ -68,45 +68,39 @@ case object AnyScalaVersion extends ScalaVersion {
  * Factory methods for producing ScalaVersions
  */
 object ScalaVersion {
-  private val dot = "\\."
-  private val dash = "\\-"
-  private def not(s:String) = s"[^${s}]"
-  private val R = s"((${not(dot)}*)(${dot}(${not(dot)}*)(${dot}(${not(dash)}*)(${dash}(.*))?)?)?)".r
-
-  def apply(versionString : String, errorHandler: String => Unit): ScalaVersion = {
-    def errorAndValue() = {
-        errorHandler(
-          s"There was a problem parsing ${versionString}. " +
-          "Versions should be in the form major[.minor[.revision]] " +
-          "where each part is a positive number, as in 2.10.1. " +
-          "The minor and revision parts are optional."
-        )
-        AnyScalaVersion
-    }
+  private val dot   = """\."""
+  private val dash  = "-"
+  private val vchar = """\d""" //"[^-+.]"
+  private val vpat  = s"(?s)($vchar+)(?:$dot($vchar+)(?:$dot($vchar+)(?:$dash(.*))?)?)?".r
+  private val rcpat = """(?i)rc(\d*)""".r
+  private val mspat = """(?i)m(\d*)""".r
+
+  def apply(versionString: String, errorHandler: String => Unit): ScalaVersion = {
+    def error() = errorHandler(
+      s"There was a problem parsing ${versionString}. " +
+      "Versions should be in the form major[.minor[.revision]] " +
+      "where each part is a positive number, as in 2.10.1. " +
+      "The minor and revision parts are optional."
+    )
 
     def toInt(s: String) = s match {
       case null | "" => 0
-      case _ => s.toInt
+      case _         => s.toInt
     }
 
-    def isInt(s: String) = util.Try(toInt(s)).isSuccess
-
     def toBuild(s: String) = s match {
       case null | "FINAL" => Final
-      case s if (s.toUpperCase.startsWith("RC") && isInt(s.substring(2))) => RC(toInt(s.substring(2)))
-      case s if (s.toUpperCase.startsWith("M") && isInt(s.substring(1))) => Milestone(toInt(s.substring(1)))
-      case _ => Development(s)
+      case rcpat(i)       => RC(toInt(i))
+      case mspat(i)       => Milestone(toInt(i))
+      case _ /* | "" */   => Development(s)
     }
 
-    try versionString match {
+    versionString match {
       case "none" => NoScalaVersion
-      case "any" => AnyScalaVersion
-      case R(_, majorS, _, minorS, _, revS, _, buildS) =>
+      case "any"  => AnyScalaVersion
+      case vpat(majorS, minorS, revS, buildS) =>
         SpecificScalaVersion(toInt(majorS), toInt(minorS), toInt(revS), toBuild(buildS))
-      case _ =>
-        errorAndValue()
-    } catch {
-      case e: NumberFormatException => errorAndValue()
+      case _      => error() ; AnyScalaVersion
     }
   }