Add support for parsing Scylla RC version numbers

Add support for parsing Scylla RC version numbers, such as 4.3.rc5.
For it to co-exist with existing VersionNumber, 4.3.rc5 is parsed into
4.3.0-rc5.

Author: avelanarius

driver-core/src/main/java/com/datastax/driver/core/VersionNumber.java

@@ -34,7 +34,7 @@
 public class VersionNumber implements Comparable<VersionNumber> {
 
   private static final String VERSION_REGEXP =
-      "(\\d+)\\.(\\d+)(\\.\\d+)?(\\.\\d+)?([~\\-]\\w[.\\w]*(?:\\-\\w[.\\w]*)*)?(\\+[.\\w]+)?";
+      "(\\d+)\\.(\\d+)(\\.(?:rc)?\\d+)?(\\.\\d+)?([~\\-]\\w[.\\w]*(?:\\-\\w[.\\w]*)*)?(\\+[.\\w]+)?";
   private static final Pattern pattern = Pattern.compile(VERSION_REGEXP);
 
   private final int major;
@@ -79,8 +79,9 @@ public static VersionNumber parse(String version) {
       int minor = Integer.parseInt(matcher.group(2));
 
       String pa = matcher.group(3);
+      boolean isRC = pa != null && pa.startsWith(".rc"); // Detect Scylla naming convention: X.Y.rcZ
       int patch =
-          pa == null || pa.isEmpty()
+          pa == null || pa.isEmpty() || isRC
               ? 0
               : Integer.parseInt(
                   pa.substring(1)); // dropping the initial '.' since it's included this time
@@ -94,10 +95,12 @@ public static VersionNumber parse(String version) {
 
       String pr = matcher.group(5);
       String[] preReleases =
-          pr == null || pr.isEmpty()
-              ? null
-              : pr.substring(1)
-                  .split("\\-"); // drop initial '-' or '~' then split on the remaining ones
+          isRC
+              ? new String[] {pa.substring(1)}
+              : pr == null || pr.isEmpty()
+                  ? null
+                  : pr.substring(1)
+                      .split("\\-"); // drop initial '-' or '~' then split on the remaining ones
 
       String bl = matcher.group(6);
       String build = bl == null || bl.isEmpty() ? null : bl.substring(1); // drop the initial '+'

driver-core/src/test/java/com/datastax/driver/core/VersionNumberTest.java

@@ -106,6 +106,14 @@ public void should_treat_same_prerelease_equal() {
     assertThat(version1.hashCode()).isEqualTo(version2.hashCode());
   }
 
+  @Test(groups = "unit")
+  public void should_parse_scylla_release_candidates() {
+    assertThat(VersionNumber.parse("4.3.rc5"))
+        .hasMajorMinorPatch(4, 3, 0)
+        .hasToString("4.3.0-rc5")
+        .hasPreReleaseLabels("rc5");
+  }
+
   private void assertOrder(String version1, String version2, int expected) {
     assertThat(VersionNumber.parse(version1).compareTo(VersionNumber.parse(version2)))
         .isEqualTo(expected);