Index: /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/MemberTableModel.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/MemberTableModel.java	(revision 10776)
+++ /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/MemberTableModel.java	(revision 10777)
@@ -46,4 +46,5 @@
 import org.openstreetmap.josm.gui.util.GuiHelper;
 import org.openstreetmap.josm.gui.widgets.OsmPrimitivesTableModel;
+import org.openstreetmap.josm.tools.bugreport.BugReport;
 
 public class MemberTableModel extends AbstractTableModel
@@ -807,8 +808,12 @@
 
     WayConnectionType getWayConnection(int i) {
-        if (connectionType == null) {
-            connectionType = wayConnectionTypeCalculator.updateLinks(members);
-        }
-        return connectionType.get(i);
+        try {
+            if (connectionType == null) {
+                connectionType = wayConnectionTypeCalculator.updateLinks(members);
+            }
+            return connectionType.get(i);
+        } catch (RuntimeException e) {
+            throw BugReport.intercept(e).put("i", i).put("members", members).put("relation", relation);
+        }
     }
 
Index: /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/sort/WayConnectionTypeCalculator.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/sort/WayConnectionTypeCalculator.java	(revision 10776)
+++ /trunk/src/org/openstreetmap/josm/gui/dialogs/relation/sort/WayConnectionTypeCalculator.java	(revision 10777)
@@ -13,4 +13,5 @@
 import org.openstreetmap.josm.data.osm.Way;
 import org.openstreetmap.josm.gui.dialogs.relation.sort.WayConnectionType.Direction;
+import org.openstreetmap.josm.tools.bugreport.BugReport;
 
 public class WayConnectionTypeCalculator {
@@ -41,58 +42,26 @@
 
         for (int i = 0; i < members.size(); ++i) {
-            final RelationMember m = members.get(i);
-            if (!m.isWay() || m.getWay() == null || m.getWay().isIncomplete()) {
-                if (i > 0) {
-                    makeLoopIfNeeded(con, i-1);
-                }
-                con.set(i, new WayConnectionType());
-                firstGroupIdx = i;
-                continue;
-            }
-
-            WayConnectionType wct = new WayConnectionType(false);
-            wct.linkPrev = i > 0 && con.get(i-1) != null && con.get(i-1).isValid();
-            wct.direction = NONE;
-
-            if (RelationSortUtils.isOneway(m)) {
-                if (lastWct != null && lastWct.isOnewayTail) {
-                    wct.isOnewayHead = true;
-                }
-                if (lastBackwardWay == UNCONNECTED && lastForwardWay == UNCONNECTED) { //Beginning of new oneway
-                    wct.isOnewayHead = true;
-                    lastForwardWay = i-1;
-                    lastBackwardWay = i-1;
-                    onewayBeginning = true;
-                }
-            }
-
-            if (wct.linkPrev) {
-                if (lastBackwardWay != UNCONNECTED && lastForwardWay != UNCONNECTED) {
-                    determineOnewayConnectionType(con, m, i, wct);
-                    if (!wct.linkPrev) {
-                        firstGroupIdx = i;
-                    }
-                }
-
-                if (!RelationSortUtils.isOneway(m) && lastWct != null) {
-                    wct.direction = determineDirection(i-1, lastWct.direction, i);
-                    wct.linkPrev = wct.direction != NONE;
-                }
-            }
-
-            if (!wct.linkPrev) {
-                wct.direction = determineDirectionOfFirst(i, m);
-                if (RelationSortUtils.isOneway(m)) {
-                    wct.isOnewayLoopForwardPart = true;
-                    lastForwardWay = i;
-                }
-            }
-
-            wct.linkNext = false;
-            if (lastWct != null) {
-                lastWct.linkNext = wct.linkPrev;
-            }
-            con.set(i, wct);
-            lastWct = wct;
+            try {
+                lastWct = updateLinksFor(con, lastWct, i);
+            } catch (RuntimeException e) {
+                int index = i;
+                throw BugReport.intercept(e).put("i", i).put("member", () -> members.get(index)).put("con", con);
+            }
+        }
+        makeLoopIfNeeded(con, members.size()-1);
+
+        return con;
+    }
+
+    private WayConnectionType updateLinksFor(final List<WayConnectionType> con, WayConnectionType lastWct, int i) {
+        final RelationMember m = members.get(i);
+        if (isNoHandleableWay(m)) {
+            if (i > 0) {
+                makeLoopIfNeeded(con, i-1);
+            }
+            con.set(i, new WayConnectionType());
+            firstGroupIdx = i;
+        } else {
+            WayConnectionType wct = computeNextWayConnection(con, lastWct, i, m);
 
             if (!wct.linkPrev) {
@@ -102,8 +71,63 @@
                 firstGroupIdx = i;
             }
-        }
-        makeLoopIfNeeded(con, members.size()-1);
-
-        return con;
+            lastWct = wct;
+        }
+        return lastWct;
+    }
+
+    private static boolean isNoHandleableWay(final RelationMember m) {
+        return !m.isWay() || m.getWay() == null || m.getWay().isIncomplete();
+    }
+
+    private WayConnectionType computeNextWayConnection(final List<WayConnectionType> con, WayConnectionType lastWct, int i,
+            final RelationMember m) {
+        WayConnectionType wct = new WayConnectionType(false);
+        wct.linkPrev = i > 0 && con.get(i-1) != null && con.get(i-1).isValid();
+        wct.direction = NONE;
+
+        if (RelationSortUtils.isOneway(m)) {
+            handleOneway(lastWct, i, wct);
+        }
+
+        if (wct.linkPrev) {
+            if (lastBackwardWay != UNCONNECTED && lastForwardWay != UNCONNECTED) {
+                determineOnewayConnectionType(con, m, i, wct);
+                if (!wct.linkPrev) {
+                    firstGroupIdx = i;
+                }
+            }
+
+            if (!RelationSortUtils.isOneway(m) && lastWct != null) {
+                wct.direction = determineDirection(i-1, lastWct.direction, i);
+                wct.linkPrev = wct.direction != NONE;
+            }
+        }
+
+        if (!wct.linkPrev) {
+            wct.direction = determineDirectionOfFirst(i, m);
+            if (RelationSortUtils.isOneway(m)) {
+                wct.isOnewayLoopForwardPart = true;
+                lastForwardWay = i;
+            }
+        }
+
+        wct.linkNext = false;
+        if (lastWct != null) {
+            lastWct.linkNext = wct.linkPrev;
+        }
+        con.set(i, wct);
+        return wct;
+    }
+
+    private void handleOneway(WayConnectionType lastWct, int i, WayConnectionType wct) {
+        if (lastWct != null && lastWct.isOnewayTail) {
+            wct.isOnewayHead = true;
+        }
+        if (lastBackwardWay == UNCONNECTED && lastForwardWay == UNCONNECTED) { //Beginning of new oneway
+            wct.isOnewayHead = true;
+            lastForwardWay = i-1;
+            lastBackwardWay = i-1;
+            onewayBeginning = true;
+        }
     }