Support Gerrit < 2.15

Check if Gerrit server version is < 2.15 and
remove unsupported options before using changes API.

Change-id: I45765e594503d0836a73913643f5923b5ed1bb7e

Author: Grzegorz Golawski

src/main/java/jenkins/plugins/gerrit/ProjectChanges.java

@@ -14,10 +14,14 @@
 
 package jenkins.plugins.gerrit;
 
+import com.google.common.annotations.VisibleForTesting;
 import com.google.gerrit.extensions.api.GerritApi;
+import com.google.gerrit.extensions.client.ListChangesOption;
 import com.google.gerrit.extensions.common.ChangeInfo;
 import com.google.gerrit.extensions.restapi.RestApiException;
+import java.util.EnumSet;
 import java.util.Optional;
+import java.util.logging.Level;
 import java.util.logging.Logger;
 
 class ProjectChanges {
@@ -31,11 +35,53 @@ class ProjectChanges {
 
   public Optional<ChangeInfo> get(int changeNumber) {
     try {
-      return Optional.ofNullable(gerritApi.changes().id(changeNumber).get());
+      EnumSet<ListChangesOption> options = EnumSet.allOf(ListChangesOption.class);
+      options.remove(ListChangesOption.CHECK);
+      if (isVersionBelow215(gerritApi.config().server().getVersion())) {
+        options.remove(ListChangesOption.TRACKING_IDS);
+        options.remove(ListChangesOption.SKIP_MERGEABLE);
+      }
+      return Optional.ofNullable(gerritApi.changes().id(changeNumber).get(options));
     } catch (RestApiException e) {
       LOGGER.severe(String.format("Unable to retrieve change %d", changeNumber));
       LOGGER.throwing(ProjectChanges.class.getName(), "get", e);
       return Optional.empty();
     }
   }
+
+  @VisibleForTesting
+  boolean isVersionBelow215(String version) {
+    if (version == null) {
+      return false;
+    }
+
+    if (version.equals("<2.8")) {
+      return true;
+    }
+
+    String[] versionSplit = version.split("\\.");
+    if (versionSplit.length == 0) {
+      return false;
+    }
+    try {
+      int majorVersion = Integer.parseInt(versionSplit[0]);
+      if (majorVersion < 2) {
+        return true;
+      }
+      if (majorVersion > 2) {
+        return false;
+      }
+      if (versionSplit.length < 2) {
+        return true;
+      }
+      int minorVersion = Integer.parseInt(versionSplit[1]);
+      if (minorVersion < 15) {
+        return true;
+      }
+      return false;
+    } catch (NumberFormatException e) {
+      LOGGER.log(Level.SEVERE, "Unable to parse Gerrit version " + version, e);
+      return false;
+    }
+  }
 }

src/test/java/jenkins/plugins/gerrit/ProjectChangesTest.java

@@ -0,0 +1,53 @@
+// Copyright (C) 2019 GerritForge Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package jenkins.plugins.gerrit;
+
+import static org.junit.Assert.*;
+
+import org.junit.Test;
+
+public class ProjectChangesTest {
+
+  @Test
+  public void testisVersionBelow215() throws Exception {
+    ProjectChanges pc = new ProjectChanges(null);
+
+    assertTrue(pc.isVersionBelow215("1"));
+    assertTrue(pc.isVersionBelow215("1.0"));
+    assertTrue(pc.isVersionBelow215("1.1.1"));
+    assertTrue(pc.isVersionBelow215("<2.8"));
+    assertTrue(pc.isVersionBelow215("2"));
+    assertTrue(pc.isVersionBelow215("2.0"));
+    assertTrue(pc.isVersionBelow215("2.0.19"));
+    assertTrue(pc.isVersionBelow215("2.14"));
+    assertTrue(pc.isVersionBelow215("2.14.99"));
+
+    assertFalse(pc.isVersionBelow215("2.15"));
+    assertFalse(pc.isVersionBelow215("2.15.0"));
+    assertFalse(pc.isVersionBelow215("2.15.99"));
+    assertFalse(pc.isVersionBelow215("2.16"));
+    assertFalse(pc.isVersionBelow215("3"));
+    assertFalse(pc.isVersionBelow215("3.0"));
+    assertFalse(pc.isVersionBelow215("3.0.0"));
+    assertFalse(pc.isVersionBelow215("3.1"));
+
+    assertFalse(pc.isVersionBelow215(null));
+    assertFalse(pc.isVersionBelow215(""));
+    assertFalse(pc.isVersionBelow215(" "));
+    assertFalse(pc.isVersionBelow215("."));
+    assertFalse(pc.isVersionBelow215(".."));
+    assertFalse(pc.isVersionBelow215("Error"));
+  }
+}