From 14f3ce0622d3aed0e0db9afb6afc9ef6b450fc51 Mon Sep 17 00:00:00 2001
From: "Nadya.Zabrodina" <Nadya.Zabrodina@jetbrains.com>
Date: Thu, 7 Feb 2013 19:50:05 +0400
Subject: [PATCH] IDEA-99083 Conflict Resolver displays wrong base version when
 using Mercurial / hg

*Get common ancestor for 2 revisions using hg log command.
---
 .../hg4idea/provider/HgMergeProvider.java     | 29 +++++++++++++++----
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/plugins/hg4idea/src/org/zmlx/hg4idea/provider/HgMergeProvider.java b/plugins/hg4idea/src/org/zmlx/hg4idea/provider/HgMergeProvider.java
index 8a93dca6f04e..afd3d9c1bc75 100644
--- a/plugins/hg4idea/src/org/zmlx/hg4idea/provider/HgMergeProvider.java
+++ b/plugins/hg4idea/src/org/zmlx/hg4idea/provider/HgMergeProvider.java
@@ -26,15 +26,18 @@ import com.intellij.openapi.vfs.VirtualFile;
 import com.intellij.vcsUtil.VcsRunnable;
 import com.intellij.vcsUtil.VcsUtil;
 import org.jetbrains.annotations.NotNull;
-import org.zmlx.hg4idea.HgContentRevision;
-import org.zmlx.hg4idea.HgFile;
-import org.zmlx.hg4idea.HgRevisionNumber;
+import org.zmlx.hg4idea.*;
+import org.zmlx.hg4idea.action.HgCommandResultNotifier;
+import org.zmlx.hg4idea.command.HgLogCommand;
+import org.zmlx.hg4idea.execution.HgCommandException;
 import org.zmlx.hg4idea.util.HgUtil;
 import org.zmlx.hg4idea.command.HgResolveCommand;
 import org.zmlx.hg4idea.command.HgWorkingCopyRevisionsCommand;
 
 import java.io.File;
 import java.io.IOException;
+import java.util.ArrayList;
+import java.util.List;
 
 /**
  * @author Kirill Likhodedov
@@ -57,7 +60,7 @@ public class HgMergeProvider implements MergeProvider {
         final VirtualFile repo = HgUtil.getHgRootOrThrow(myProject, file);
         final HgFile hgFile = new HgFile(myProject, file);
 
-        HgRevisionNumber serverRevisionNumber, baseRevisionNumber, localRevisionNumber;
+        HgRevisionNumber serverRevisionNumber, baseRevisionNumber = null, localRevisionNumber;
         // there are two possibilities: we have checked in local changes in the selected file or we didn't.
         if (wasFileCheckedIn(repo, file)) {
           // 1. We checked in.
@@ -74,9 +77,23 @@ public class HgMergeProvider implements MergeProvider {
           localRevisionNumber = parents.first;
           final HgContentRevision local = new HgContentRevision(myProject, hgFile, localRevisionNumber);
           mergeData.CURRENT = local.getContentAsBytes();
-          // we are sure that we have a grandparent, because otherwise we'll get "repository is unrelated" error while pulling,
+          // we are sure that we have a common ancestor, because otherwise we'll get "repository is unrelated" error while pulling,
           // due to different root changesets which is prohibited.
-          baseRevisionNumber = command.parents(repo, file, localRevisionNumber).first;
+          // Find common ancestor of two revisions : hg log -r "ancestor(rev1,ancestor(rev2,rev3))"
+          List<String> arguments = new ArrayList<String>();
+          arguments.add("-r");
+          arguments.add("\"ancestor(" + localRevisionNumber.getRevision() + ',' + serverRevisionNumber.getRevision() + ")\"");
+          final List<HgFileRevision> revisions;
+          try {
+            revisions = new HgLogCommand(myProject).execute(new HgFile(myProject, file), -1, false, arguments);
+            if (revisions != null && !revisions.isEmpty()) {
+              baseRevisionNumber = revisions.get(0).getRevisionNumber();
+            }
+          }
+          catch (HgCommandException e) {
+            new HgCommandResultNotifier(myProject)
+              .notifyError(null, HgVcsMessages.message("hg4idea.error.log.command.execution"), e.getMessage());
+          }
         } else {
           // 2. local changes are not checked in.
           // then there is only one parent, which is server changes.