--- a/mercurial-server/src/jetbrains/buildServer/buildTriggers/vcs/mercurial/MercurialVcsSupport.java	Tue Jan 11 15:15:16 2011 +0300
+++ b/mercurial-server/src/jetbrains/buildServer/buildTriggers/vcs/mercurial/MercurialVcsSupport.java	Tue Jan 11 15:24:58 2011 +0300
@@ -52,7 +52,7 @@
  * <p>Working copy of repository is created in the $TEAMCITY_DATA_PATH/system/caches/hg_&lt;hash code> folder.
  * <p>Personal builds (remote runs) are not yet supported, they require corresponding functionality from the IDE.
  */
-public class MercurialVcsSupport extends ServerVcsSupport implements LabelingSupport, VcsFileContentProvider {
+public class MercurialVcsSupport extends ServerVcsSupport implements LabelingSupport, VcsFileContentProvider, BranchSupport {
   private ConcurrentMap<String, Lock> myWorkDirLocks= new ConcurrentHashMap<String, Lock>();
   private VcsManager myVcsManager;
   private File myDefaultWorkFolderParent;
@@ -410,6 +410,25 @@
     return this;
   }
 
+  public List<ModificationData> collectChanges(@NotNull VcsRoot fromRoot, @NotNull String fromRootRevision,
+                                               @NotNull VcsRoot toRoot, @Nullable String toRootRevision,
+                                               @NotNull CheckoutRules checkoutRules) throws VcsException {
+    //we get all branches while clone, if vcs roots are related it is doesn't matter in which one search for branch point
+    syncClonedRepository(fromRoot);
+    String branchPoint = getBranchPoint(fromRoot, fromRootRevision, toRootRevision);
+    return ((CollectChangesByCheckoutRules) getCollectChangesPolicy()).collectChanges(fromRoot, branchPoint, toRootRevision, checkoutRules);
+  }
+
+  private String getBranchPoint(@NotNull VcsRoot root, String branchOneRev, String branchTwoRev) throws VcsException {
+    Settings settings = createSettings(root);
+    LogCommand lc = new LogCommand(settings);
+    lc.setFromRevId(new ChangeSetRevision(branchOneRev).getId());
+    lc.setToRevId(new ChangeSetRevision(branchTwoRev).getId());
+    lc.setLimit(1);
+    List<ChangeSet> changeSets = lc.execute();
+    return changeSets.get(0).getParents().get(0).getId();
+  }
+
   @NotNull
   public CollectChangesPolicy getCollectChangesPolicy() {
     return new CollectChangesByCheckoutRules() {