#
#
# patch "NEWS"
#  from [20cc058bff304df18e778f57a1c4676610bf2534]
#    to [a5c303d1604b8e394608ee7a8fdfd03e774a02c3]
# 
# patch "database.cc"
#  from [25a7d09b691fa29743249d4151dc27bab18c7923]
#    to [5a61650edb2b4f71f83c39f327062de5ed827485]
# 
# patch "database_check.cc"
#  from [eb2f10d33d8a4b345982a09ccb29a3d4235c06ab]
#    to [beb0e60421b8bf7552071a9af31ef6630cfd3b51]
# 
# patch "tests/db_check_and_non-serious_errors/__driver__.lua"
#  from [489d591cb8383b6cfb17c02be4dc774cfa1e63cc]
#    to [908eadb2fc3c9e4ea028ff5b1e2e27bf01821406]
#
============================================================
--- NEWS	20cc058bff304df18e778f57a1c4676610bf2534
+++ NEWS	a5c303d1604b8e394608ee7a8fdfd03e774a02c3
@@ -79,6 +79,14 @@ xxx xxx xx xx:xx:xx UTC 2010
           interrupted (^C). This was broken in 0.47 when it was fixed to not
           throw an exception on being interrupted.
 
+        - In 0.46 and 0.47, monotone could sometimes get confused about which
+          revisions were the heads of a particular branch. This would happen
+          when a new branch cert was added to a revision that was an ancestor
+          of one or more of the current heads of the branch, most commonly
+          during netsync when multiple people had performed identical merges.
+          This is fixed now. If your database currently gives incorrect 'heads'
+          results, you can fix it by either running 'mtn db regenerate_caches'.
+
         Other
 
         - Support for the diffuse merger (http://diffuse.sourceforge.net)
============================================================
--- database.cc	25a7d09b691fa29743249d4151dc27bab18c7923
+++ database.cc	5a61650edb2b4f71f83c39f327062de5ed827485
@@ -3607,6 +3607,7 @@ database::record_as_branch_leaf(cert_val
     return; // already recorded (must be adding a second branch cert)
 
   bool all_parents_were_leaves = true;
+  bool some_ancestor_was_leaf = false;
   for (set<revision_id>::const_iterator p = parents.begin();
        p != parents.end(); ++p)
     {
@@ -3615,6 +3616,7 @@ database::record_as_branch_leaf(cert_val
         all_parents_were_leaves = false;
       else
         {
+          some_ancestor_was_leaf = true;
           imp->execute(query("DELETE FROM branch_leaves "
                              "WHERE branch = ? AND revision_id = ?")
                        % blob(branch()) % blob(l->inner()()));
@@ -3637,6 +3639,7 @@ database::record_as_branch_leaf(cert_val
         {
           if (is_a_ancestor_of_b(*r, rev))
             {
+              some_ancestor_was_leaf = true;
               imp->execute(query("DELETE FROM branch_leaves "
                                  "WHERE branch = ? AND revision_id = ?")
                            % blob(branch()) % blob(r->inner()()));
@@ -3644,6 +3647,23 @@ database::record_as_branch_leaf(cert_val
         }
     }
 
+  // are we really a leaf (ie, not an ancestor of an existing leaf)?
+  if (!some_ancestor_was_leaf)
+    {
+      bool really_a_leaf = true;
+      for (set<revision_id>::const_iterator r = current_leaves.begin();
+           r != current_leaves.end(); ++r)
+        {
+          if (is_a_ancestor_of_b(rev, *r))
+            {
+              really_a_leaf = false;
+              break;
+            }
+        }
+      if (!really_a_leaf)
+        return;
+    }
+
   imp->execute(query("INSERT INTO branch_leaves(branch, revision_id) "
                      "VALUES (?, ?)")
                % blob(branch()) % blob(rev.inner()()));
============================================================
--- database_check.cc	eb2f10d33d8a4b345982a09ccb29a3d4235c06ab
+++ database_check.cc	beb0e60421b8bf7552071a9af31ef6630cfd3b51
@@ -641,7 +641,19 @@ check_branch_leaves(database & db, map<s
           set<revision_id> computed_leaves;
 
           db.get_branch_leaves(i->value, cached_leaves);
-          db.compute_branch_leaves(i->value, computed_leaves);
+          try
+            {
+              db.compute_branch_leaves(i->value, computed_leaves);
+            }
+          catch (std::exception & e)
+            {
+              if (string(e.what()).find("height") != string::npos)
+                {
+                  L(FL("error loading height when checking heads of '%s'") % i->value);
+                }
+              else
+                throw;
+            }
 
           checked_branches[name].heads_ok = cached_leaves == computed_leaves;
           ++ticks;
============================================================
--- tests/db_check_and_non-serious_errors/__driver__.lua	489d591cb8383b6cfb17c02be4dc774cfa1e63cc
+++ tests/db_check_and_non-serious_errors/__driver__.lua	908eadb2fc3c9e4ea028ff5b1e2e27bf01821406
@@ -23,6 +23,10 @@ end
   local str = string.format("delete from %s where %s = x'%s'", a, b, del_rev)
   check(mtn("db", "execute", str), 0, false, false)
 end
+check(mtn("db", "execute",
+	  string.format("update branch_leaves set revision_id = x'%s' where revision_id = x'%s'",
+		  rev, del_rev)),
+      0, false, false)
 
 -- and also a few unused files shall float about
 check(mtn("fload"), 0, false, false, {"fileX"})