Index: /trunk/src/org/openstreetmap/josm/data/validation/OsmValidator.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/data/validation/OsmValidator.java	(revision 4050)
+++ /trunk/src/org/openstreetmap/josm/data/validation/OsmValidator.java	(revision 4051)
@@ -31,4 +31,5 @@
 import org.openstreetmap.josm.data.validation.tests.DuplicateNode;
 import org.openstreetmap.josm.data.validation.tests.DuplicateWay;
+import org.openstreetmap.josm.data.validation.tests.DuplicateRelation;
 import org.openstreetmap.josm.data.validation.tests.DuplicatedWayNodes;
 import org.openstreetmap.josm.data.validation.tests.MultipolygonTest;
@@ -95,4 +96,5 @@
             RelationChecker.class, // ID  1701 ..  1799
             TurnrestrictionTest.class, // ID  1801 ..  1899
+            DuplicateRelation.class, // ID 1901 .. 1999
     };
 
Index: /trunk/src/org/openstreetmap/josm/data/validation/tests/DuplicateRelation.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/data/validation/tests/DuplicateRelation.java	(revision 4051)
+++ /trunk/src/org/openstreetmap/josm/data/validation/tests/DuplicateRelation.java	(revision 4051)
@@ -0,0 +1,283 @@
+// License: GPL. See LICENSE file for details.
+package org.openstreetmap.josm.data.validation.tests;
+
+import static org.openstreetmap.josm.tools.I18n.tr;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashSet;
+import java.util.LinkedList;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Vector;
+
+import org.openstreetmap.josm.Main;
+import org.openstreetmap.josm.command.ChangeCommand;
+import org.openstreetmap.josm.command.Command;
+import org.openstreetmap.josm.command.DeleteCommand;
+import org.openstreetmap.josm.command.SequenceCommand;
+import org.openstreetmap.josm.data.coor.LatLon;
+import org.openstreetmap.josm.data.osm.Node;
+import org.openstreetmap.josm.data.osm.OsmPrimitive;
+import org.openstreetmap.josm.data.osm.OsmPrimitiveType;
+import org.openstreetmap.josm.data.osm.Relation;
+import org.openstreetmap.josm.data.osm.RelationMember;
+import org.openstreetmap.josm.data.osm.Way;
+import org.openstreetmap.josm.gui.progress.ProgressMonitor;
+import org.openstreetmap.josm.data.validation.Severity;
+import org.openstreetmap.josm.data.validation.Test;
+import org.openstreetmap.josm.data.validation.TestError;
+import org.openstreetmap.josm.tools.MultiMap;
+/**
+ * Tests if there are duplicate relations
+ */
+public class DuplicateRelation extends Test
+{
+
+    public class RelMember {
+        private String role;
+        private OsmPrimitiveType type;
+        private Map<String, String> tags;
+        private List<LatLon> coor;
+        private long rel_id;
+
+        @Override
+        public int hashCode() {
+            return role.hashCode()+(int)rel_id+tags.hashCode()+type.hashCode()+coor.hashCode();
+        }
+
+        @Override
+        public boolean equals(Object obj) {
+            if (!(obj instanceof RelMember)) return false;
+            RelMember rm = (RelMember) obj;
+            return rm.role.equals(role) && rm.type.equals(type) && rm.rel_id==rel_id && rm.tags.equals(tags) && rm.coor.equals(coor);
+        }
+
+        public RelMember(RelationMember src) {
+            role=src.getRole();
+            type=src.getType();
+            rel_id=0;
+            coor=new ArrayList<LatLon>();
+
+            if (src.isNode()) {
+                Node r=src.getNode();
+                tags=r.getKeys();
+                coor=new ArrayList<LatLon>(1);
+                coor.add(r.getCoor());
+            }
+            if (src.isWay()) {
+                Way r=src.getWay();
+                tags=r.getKeys();
+                List<Node> wNodes = r.getNodes();
+                coor=new ArrayList<LatLon>(wNodes.size());
+                for (int i=0;i<wNodes.size();i++) {
+                    coor.add(wNodes.get(i).getCoor());
+                }
+            }
+            if (src.isRelation()) {
+                Relation r=src.getRelation();
+                tags=r.getKeys();
+                rel_id=r.getId();
+                coor=new ArrayList<LatLon>();
+            }
+        }
+    }
+
+    private class RelationMembers {
+        public List<RelMember> members;
+        public RelationMembers(List<RelationMember> _members) {
+            members=new ArrayList<RelMember>(_members.size());
+            for (int i=0;i<_members.size();i++) {
+                members.add(new RelMember(_members.get(i)));
+            }
+        }
+        @Override
+        public int hashCode() {
+            return members.hashCode();
+        }
+        @Override
+        public boolean equals(Object obj) {
+            if (!(obj instanceof RelationMembers)) return false;
+            RelationMembers rm = (RelationMembers) obj;
+            return rm.members.equals(members);
+        }
+    }
+
+    private class RelationPair {
+        public RelationMembers members;
+        public Map<String, String> keys;
+        public RelationPair(List<RelationMember> _members,Map<String, String> _keys) {
+            members=new RelationMembers(_members);
+            keys=_keys;
+        }
+        @Override
+        public int hashCode() {
+            return members.hashCode()+keys.hashCode();
+        }
+        @Override
+        public boolean equals(Object obj) {
+            if (!(obj instanceof RelationPair)) return false;
+            RelationPair rp = (RelationPair) obj;
+            return rp.members.equals(members) && rp.keys.equals(keys);
+        }
+    }
+
+    protected static int DUPLICATE_RELATION = 1901;
+    protected static int SAME_RELATION = 1902;
+
+    /** MultiMap of all relations */
+    MultiMap<RelationPair, OsmPrimitive> relations;
+
+    /** MultiMap of all relations, regardless of keys */
+    MultiMap<List<RelationMember>, OsmPrimitive> relations_nokeys;
+
+    /**
+     * Constructor
+     */
+    public DuplicateRelation()
+    {
+        super(tr("Duplicated relations")+".",
+              tr("This test checks that there are no relations with same tags and same members with same roles."));
+    }
+
+
+    @Override
+    public void startTest(ProgressMonitor monitor)
+    {
+    	super.startTest(monitor);
+        relations = new MultiMap<RelationPair, OsmPrimitive>(1000);
+        relations_nokeys = new MultiMap<List<RelationMember>, OsmPrimitive>(1000);
+    }
+
+    @Override
+    public void endTest()
+    {
+    	super.endTest();
+        for(LinkedHashSet<OsmPrimitive> duplicated : relations.values() )
+        {
+            if( duplicated.size() > 1)
+            {
+                TestError testError = new TestError(this, Severity.ERROR, tr("Duplicated relations"), DUPLICATE_RELATION, duplicated);
+                errors.add( testError );
+            }
+        }
+        relations = null;
+        for(LinkedHashSet<OsmPrimitive> duplicated : relations_nokeys.values() )
+        {
+            if( duplicated.size() > 1)
+            {
+                TestError testError = new TestError(this, Severity.WARNING, tr("Relations with same members"), SAME_RELATION, duplicated);
+                errors.add( testError );
+            }
+        }
+        relations_nokeys = null;
+    }
+
+    @Override
+    public void visit(Relation r)
+    {
+        if( !r.isUsable() )
+            return;
+        List<RelationMember> rMembers=r.getMembers();
+        Map<String, String> rkeys=r.getKeys();
+        rkeys.remove("created_by");
+        RelationPair rKey=new RelationPair(rMembers,rkeys);
+        relations.put(rKey, r);
+        relations_nokeys.put(rMembers, r);
+    }
+
+    /**
+     * Fix the error by removing all but one instance of duplicate relations
+     */
+    @Override
+    public Command fixError(TestError testError)
+    {
+        if (testError.getCode() == SAME_RELATION) return null;
+        Collection<? extends OsmPrimitive> sel = testError.getPrimitives();
+        HashSet<Relation> rel_fix = new HashSet<Relation>();
+
+        for (OsmPrimitive osm : sel)
+            if (osm instanceof Relation)
+                rel_fix.add((Relation)osm);
+
+        if( rel_fix.size() < 2 )
+            return null;
+
+        long idToKeep = 0;
+        Relation relationToKeep = rel_fix.iterator().next();
+        // Only one relation will be kept - the one with lowest positive ID, if such exist
+        // or one "at random" if no such exists. Rest of the relations will be deleted
+        for (Relation w: rel_fix) {
+            if (!w.isNew()) {
+                if (idToKeep == 0 || w.getId() < idToKeep) {
+                    idToKeep = w.getId();
+                    relationToKeep = w;
+                }
+            }
+        }
+
+        // Find the relation that is member of one or more relations. (If any)
+        Relation relationWithRelations = null;
+        List<Relation> rel_ref = null;
+        for (Relation w : rel_fix) {
+            List<Relation> rel = OsmPrimitive.getFilteredList(w.getReferrers(), Relation.class);
+            if (!rel.isEmpty()) {
+                if (relationWithRelations != null)
+                    throw new AssertionError("Cannot fix duplicate relations: More than one relation is member of another relation.");
+                relationWithRelations = w;
+                rel_ref = rel;
+            }
+        }
+
+        Collection<Command> commands = new LinkedList<Command>();
+
+        // Fix relations.
+        if (relationWithRelations != null && relationToKeep != relationWithRelations) {
+            for (Relation rel : rel_ref) {
+                Relation newRel = new Relation(rel);
+                for (int i = 0; i < newRel.getMembers().size(); ++i) {
+                    RelationMember m = newRel.getMember(i);
+                    if (relationWithRelations.equals(m.getMember())) {
+                        newRel.setMember(i, new RelationMember(m.getRole(), relationToKeep));
+                    }
+                }
+                commands.add(new ChangeCommand(rel, newRel));
+            }
+        }
+
+        //Delete all relations in the list
+        rel_fix.remove(relationToKeep);
+        commands.add(new DeleteCommand(rel_fix));
+        return new SequenceCommand(tr("Delete duplicate relations"), commands);
+    }
+
+    @Override
+    public boolean isFixable(TestError testError)
+    {
+        if (!(testError.getTester() instanceof DuplicateRelation))
+            return false;
+
+        if (testError.getCode() == SAME_RELATION) return false;
+
+        // We fix it only if there is no more than one relation that is relation member.
+        Collection<? extends OsmPrimitive> sel = testError.getPrimitives();
+        HashSet<Relation> relations = new HashSet<Relation>();
+
+        for (OsmPrimitive osm : sel)
+            if (osm instanceof Relation)
+                relations.add((Relation)osm);
+
+        if (relations.size() < 2)
+            return false;
+
+        int relationsWithRelations = 0;
+        for (Relation w : relations) {
+            List<Relation> rel = OsmPrimitive.getFilteredList(w.getReferrers(), Relation.class);
+            if (!rel.isEmpty()) {
+                ++relationsWithRelations;
+            }
+        }
+        return (relationsWithRelations <= 1);
+    }
+}
Index: /trunk/src/org/openstreetmap/josm/data/validation/tests/DuplicateWay.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/data/validation/tests/DuplicateWay.java	(revision 4050)
+++ /trunk/src/org/openstreetmap/josm/data/validation/tests/DuplicateWay.java	(revision 4051)
@@ -34,5 +34,5 @@
 {
 
-    private static class WayPair {
+    private class WayPair {
         public List<LatLon> coor;
         public Map<String, String> keys;
@@ -56,8 +56,29 @@
     }
 
+    private class WayPairNoTags {
+        public List<LatLon> coor;
+        public WayPairNoTags(List<LatLon> _coor) {
+            coor=_coor;
+        }
+        @Override
+        public int hashCode() {
+            return coor.hashCode();
+        }
+        @Override
+        public boolean equals(Object obj) {
+            if (!(obj instanceof WayPairNoTags)) return false;
+            WayPairNoTags wp = (WayPairNoTags) obj;
+            return wp.coor.equals(coor);
+        }
+    }
+
     protected static int DUPLICATE_WAY = 1401;
+    protected static int SAME_WAY = 1402;
 
     /** Bag of all ways */
     MultiMap<WayPair, OsmPrimitive> ways;
+
+    /** Bag of all ways, regardless of tags */
+    MultiMap<WayPairNoTags, OsmPrimitive> waysNoTags;
 
     /**
@@ -66,5 +87,5 @@
     public DuplicateWay() {
         super(tr("Duplicated ways."),
-                tr("This test checks that there are no ways with same tags and same node coordinates."));
+              tr("This test checks that there are no ways with same node coordinates and optionally also same tags."));
     }
 
@@ -74,4 +95,5 @@
         super.startTest(monitor);
         ways = new MultiMap<WayPair, OsmPrimitive>(1000);
+        waysNoTags = new MultiMap<WayPairNoTags, OsmPrimitive>(1000);
     }
 
@@ -85,5 +107,38 @@
             }
         }
+
+        for(Set<OsmPrimitive> sameway : waysNoTags.values()) {
+            if( sameway.size() > 1) {
+                //Report error only if at least some tags are different, as otherwise the error was already reported as duplicated ways
+                Map<String, String> tags0=null;
+                boolean skip=true;
+
+                for(OsmPrimitive o : sameway) {
+                    if (tags0==null) {
+                        tags0=o.getKeys();
+                        removeUninterestingKeys(tags0);
+                    } else {
+                        Map<String, String> tagsCmp=o.getKeys();
+                        removeUninterestingKeys(tagsCmp);
+                        if (!tagsCmp.equals(tags0)) {
+                            skip=false;
+                            break;
+                        }
+                    }
+                }
+                if (skip) continue;
+                TestError testError = new TestError(this, Severity.WARNING, tr("Ways with same position"), SAME_WAY, sameway);
+                errors.add(testError);
+            }
+        }
         ways = null;
+        waysNoTags = null;
+    }
+
+    /**
+     * Remove uninteresting keys, like created_by to normalize the tags 
+     */
+    public void removeUninterestingKeys(Map<String, String> wkeys) {
+        wkeys.remove("created_by");
     }
 
@@ -98,7 +153,9 @@
         }
         Map<String, String> wkeys = w.getKeys();
-        wkeys.remove("created_by");
+        removeUninterestingKeys(wkeys);
         WayPair wKey = new WayPair(wLat, wkeys);
         ways.put(wKey, w);
+        WayPairNoTags wKeyN = new WayPairNoTags(wLat);
+        waysNoTags.put(wKeyN, w);
     }
 
@@ -174,4 +231,7 @@
             return false;
 
+        //Do not automatically fix same ways with different tags
+        if (testError.getCode()!=DUPLICATE_WAY) return false;
+
         // We fix it only if there is no more than one way that is relation member.
         Collection<? extends OsmPrimitive> sel = testError.getPrimitives();