Merge changes Id768b4f1,Iba8447f6

* changes:
  Display only mergeable changes in Conflicts With tab
  Add 'is:mergeable' operator to find changes without merge conflict

gerrit-server/src/main/java/com/google/gerrit/server/index/ChangeField.java

@@ -349,6 +349,17 @@ public class ChangeField {
         }
       };
 
+  /** Whether the change is mergeable. */
+  public static final FieldDef<ChangeData, String> MERGEABLE =
+      new FieldDef.Single<ChangeData, String>(
+          ChangeQueryBuilder.FIELD_MERGEABLE, FieldType.EXACT, false) {
+        @Override
+        public String get(ChangeData input, FillArgs args)
+            throws OrmException {
+          return input.change(args.db).isMergeable() ? "1" : null;
+        }
+      };
+
   private static <T> List<byte[]> toProtos(ProtobufCodec<T> codec, Collection<T> objs)
       throws OrmException {
     List<byte[]> result = Lists.newArrayListWithCapacity(objs.size());

gerrit-server/src/main/java/com/google/gerrit/server/index/ChangeSchemas.java

@@ -97,6 +97,29 @@ public class ChangeSchemas {
   // For upgrade to Lucene 4.4.0 index format only.
   static final Schema<ChangeData> V4 = release(V3.getFields().values());
 
+  @SuppressWarnings("unchecked")
+  static final Schema<ChangeData> V5 = release(
+        ChangeField.LEGACY_ID,
+        ChangeField.ID,
+        ChangeField.STATUS,
+        ChangeField.PROJECT,
+        ChangeField.REF,
+        ChangeField.TOPIC,
+        ChangeField.UPDATED,
+        ChangeField.SORTKEY,
+        ChangeField.FILE,
+        ChangeField.OWNER,
+        ChangeField.REVIEWER,
+        ChangeField.COMMIT,
+        ChangeField.TR,
+        ChangeField.LABEL,
+        ChangeField.REVIEWED,
+        ChangeField.COMMIT_MESSAGE,
+        ChangeField.COMMENT,
+        ChangeField.CHANGE,
+        ChangeField.APPROVAL,
+        ChangeField.MERGEABLE);
+
   private static Schema<ChangeData> release(Collection<FieldDef<ChangeData, ?>> fields) {
     return new Schema<ChangeData>(true, fields);
   }

gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java

@@ -93,6 +93,7 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
   public static final String FIELD_HAS = "has";
   public static final String FIELD_LABEL = "label";
   public static final String FIELD_LIMIT = "limit";
+  public static final String FIELD_MERGEABLE = "mergeable";
   public static final String FIELD_MESSAGE = "message";
   public static final String FIELD_OWNER = "owner";
   public static final String FIELD_OWNERIN = "ownerin";
@@ -280,7 +281,7 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
   }
 
   @Operator
-  public Predicate<ChangeData> is(String value) {
+  public Predicate<ChangeData> is(String value) throws QueryParseException {
     if ("starred".equalsIgnoreCase(value)) {
       return new IsStarredByPredicate(args.dbProvider, currentUser);
     }
@@ -305,6 +306,11 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
       return new ReviewerPredicate(args.dbProvider, self());
     }
 
+    if ("mergeable".equalsIgnoreCase(value)) {
+      requireIndex(FIELD_IS, "mergeable");
+      return new IsMergeablePredicate(args.dbProvider);
+    }
+
     try {
       return status(value);
     } catch (IllegalArgumentException e) {

gerrit-server/src/main/java/com/google/gerrit/server/query/change/IsMergeablePredicate.java

@@ -0,0 +1,42 @@
+// Copyright (C) 2013 The Android Open Source Project
+//
+// 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 com.google.gerrit.server.query.change;
+
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.index.ChangeField;
+import com.google.gerrit.server.index.IndexPredicate;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Provider;
+
+class IsMergeablePredicate extends IndexPredicate<ChangeData> {
+  private final Provider<ReviewDb> dbProvider;
+
+  IsMergeablePredicate(Provider<ReviewDb> dbProvider) {
+    super(ChangeField.MERGEABLE, "1");
+    this.dbProvider = dbProvider;
+  }
+
+  @Override
+  public boolean match(ChangeData object) throws OrmException {
+    Change c = object.change(dbProvider);
+    return c != null && c.isMergeable();
+  }
+
+  @Override
+  public int getCost() {
+    return 1;
+  }
+}