Remove SNAPSHOT from versions in plugin descriptors

We removed leniencey from version parsing which caught problems with
-SNAPSHOT suffixes on plugin properies. This commit removes the -SNAPSHOT
from both es and the extension version and adds tests to ensure we can
parse older versions that allowed -SNAPSHOT in BWC way.

buildSrc/src/main/groovy/org/elasticsearch/gradle/plugin/PluginPropertiesTask.groovy

@@ -68,11 +68,17 @@ class PluginPropertiesTask extends Copy {
     }
 
     Map generateSubstitutions() {
+        def stringSnap = { version ->
+            if (version.endsWith("-SNAPSHOT")) {
+               return version.substring(0, version.length() - 9)
+            }
+            return version
+        }
         return [
             'name': extension.name,
             'description': extension.description,
-            'version': extension.version,
-            'elasticsearchVersion': VersionProperties.elasticsearch,
+            'version': stringSnap(extension.version),
+            'elasticsearchVersion': stringSnap(VersionProperties.elasticsearch),
             'javaVersion': project.targetCompatibility as String,
             'isolated': extension.isolated as String,
             'classname': extension.classname

core/src/main/java/org/elasticsearch/Version.java

@@ -137,6 +137,10 @@ public class Version {
         if (!Strings.hasLength(version)) {
             return Version.CURRENT;
         }
+        final boolean snapshot; // this is some BWC for 2.x and before indices
+        if (snapshot = version.endsWith("-SNAPSHOT")) {
+            version = version.substring(0, version.length() - 9);
+        }
         String[] parts = version.split("\\.|\\-");
         if (parts.length < 3 || parts.length > 4) {
             throw new IllegalArgumentException("the version needs to contain major, minor, and revision, and optionally the build: " + version);
@@ -144,6 +148,9 @@ public class Version {
 
         try {
             final int rawMajor = Integer.parseInt(parts[0]);
+            if (rawMajor >= 5 && snapshot) { // we don't support snapshot as part of the version here anymore
+                throw new IllegalArgumentException("illegal version format - snapshots are only supported until version 2.x");
+            }
             final int betaOffset = rawMajor < 5 ? 0 : 25;
             //we reverse the version id calculation based on some assumption as we can't reliably reverse the modulo
             final int major = rawMajor * 1000000;

core/src/test/java/org/elasticsearch/VersionTests.java

@@ -198,6 +198,13 @@ public class VersionTests extends ESTestCase {
         expectThrows(IllegalArgumentException.class, () -> {
             Version.fromString("5.0.0-alph2");
         });
+        assertSame(Version.CURRENT, Version.fromString(Version.CURRENT.toString()));
+
+        assertSame(Version.fromString("2.0.0-SNAPSHOT"), Version.fromString("2.0.0"));
+
+        expectThrows(IllegalArgumentException.class, () -> {
+            Version.fromString("5.0.0-SNAPSHOT");
+        });
     }
 
     public void testParseLenient() {