SI-9750 Spec check major.minor.security

Don't assume spec is just major, but allow arbitrary version
number for both spec value and user value to check.

Only the first three dot-separated fields are considered,
after skipping optional leading value "1" in legacy format.

Minimal validity checks of user arg are applied. Leading three
fields, if present, must be number values, but subsequent
fields are ignored.

Note that a version number is not a version string, which
optionally includes pre and build info, `9-ea+109`.

1 files changed, 47 insertions, 21 deletions

diff --git a/src/library/scala/util/Properties.scala b/src/library/scala/util/Properties.scala
index 1bdf50bac2..8722294dde 100644
--- a/src/library/scala/util/Properties.scala
+++ b/src/library/scala/util/Properties.scala
@@ -168,33 +168,59 @@ private[scala] trait PropertiesTrait {
 
   /** Compares the given specification version to the specification version of the platform.
    *
-   * @param version a specification version number (legacy forms acceptable)
-   * @return `true` iff the specification version of the current runtime
-   * is equal to or higher than the version denoted by the given string.
-   * @throws NumberFormatException if the given string is not a version string
+   *  @param version a specification version number (legacy forms acceptable)
+   *  @return `true` if the specification version of the current runtime
+   *    is equal to or higher than the version denoted by the given string.
+   *  @throws NumberFormatException if the given string is not a version string
    *
-   * @example {{{
-   * // In this example, the runtime's Java specification is assumed to be at version 8.
-   * isJavaAtLeast("1.6")            // true
-   * isJavaAtLeast("1.8")            // true
-   * isJavaAtLeast("8")              // true
-   * isJavaAtLeast("9")              // false
-   * isJavaAtLeast("1.9")            // throws
-   * }}}
+   *  @example {{{
+   *  // In this example, the runtime's Java specification is assumed to be at version 8.
+   *  isJavaAtLeast("1.8")            // true
+   *  isJavaAtLeast("8")              // true
+   *  isJavaAtLeast("9")              // false
+   *  isJavaAtLeast("9.1")            // false
+   *  isJavaAtLeast("1.9")            // throws
+   *  }}}
    */
   def isJavaAtLeast(version: String): Boolean = {
-    def versionOf(s: String): Int = s.indexOf('.') match {
-      case 1 if s.charAt(0) == '1' =>
-        val v = s.substring(2).toInt
-        if (v < 9) v else -1
-      case -1 => s.toInt
-      case _  => -1
+    def versionOf(s: String, depth: Int): (Int, String) =
+      s.indexOf('.') match {
+        case 0 =>
+          (-2, s.substring(1))
+        case 1 if depth == 0 && s.charAt(0) == '1' =>
+          val r0 = s.substring(2)
+          val (v, r) = versionOf(r0, 1)
+          val n = if (v > 8 || r0.isEmpty) -2 else v   // accept 1.8, not 1.9 or 1.
+          (n, r)
+        case -1 =>
+          val n = if (!s.isEmpty) s.toInt else if (depth == 0) -2 else 0
+          (n, "")
+        case i  =>
+          val r = s.substring(i + 1)
+          val n = if (depth < 2 && r.isEmpty) -2 else s.substring(0, i).toInt
+          (n, r)
+      }
+    def compareVersions(s: String, v: String, depth: Int): Int = {
+      if (depth >= 3) 0
+      else {
+        val (sn, srest) = versionOf(s, depth)
+        val (vn, vrest) = versionOf(v, depth)
+        if (vn < 0) -2
+        else if (sn < vn) -1
+        else if (sn > vn) 1
+        else compareVersions(srest, vrest, depth + 1)
+      }
+    }
+    compareVersions(javaSpecVersion, version, 0) match {
+      case -2 => throw new NumberFormatException(s"Not a version: $version")
+      case i  => i >= 0
     }
-    val v = versionOf(version)
-    if (v < 0) throw new NumberFormatException(s"Not a version: $version")
-    versionOf(javaSpecVersion) >= v
   }
 
+  /** Tests whether the major version of the platform specification is at least the given value.
+   *
+   *  @param version a major version number
+   */
   def isJavaAtLeast(version: Int): Boolean = isJavaAtLeast(version.toString)
 
   // provide a main method so version info can be obtained by running this