[405543] An unsettable many-valued reference that is set to an empty list is unset on new transaction

https://bugs.eclipse.org/bugs/show_bug.cgi?id=405543

11 files changed, 148 insertions, 106 deletions

diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractBasicListTableMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractBasicListTableMapping.java
index bbb8163fc6..c579cd8377 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractBasicListTableMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractBasicListTableMapping.java
@@ -252,10 +252,9 @@ public abstract class AbstractBasicListTableMapping implements IListMapping3, IM
 
     public void visit(CDOUnsetFeatureDelta delta)
     {
-      // TODO Shouldn't that be "!unsettable"?!
-      if (delta.getFeature().isUnsettable())
+      if (!delta.getFeature().isUnsettable())
       {
-        throw new IllegalArgumentException("Feature is unsettable: " + delta);
+        throw new IllegalArgumentException("Feature is not unsettable: " + delta);
       }
 
       if (TRACER.isEnabled())
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractFeatureMapTableMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractFeatureMapTableMapping.java
index e70bb8024f..f8889bc24c 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractFeatureMapTableMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractFeatureMapTableMapping.java
@@ -306,10 +306,16 @@ public abstract class AbstractFeatureMapTableMapping extends AbstractBasicListTa
 
   public void readValues(IDBStoreAccessor accessor, InternalCDORevision revision, int listChunk)
   {
-    MoveableList<Object> list = revision.getList(getFeature());
+    MoveableList<Object> list = revision.getListOrNull(getFeature());
+    if (list == null)
+    {
+      // Nothing to read take shortcut.
+      return;
+    }
+
     if (listChunk == 0 || list.size() == 0)
     {
-      // nothing to read take shortcut
+      // Nothing to read take shortcut.
       return;
     }
 
@@ -464,12 +470,14 @@ public abstract class AbstractFeatureMapTableMapping extends AbstractBasicListTa
 
   public void writeValues(IDBStoreAccessor accessor, InternalCDORevision revision)
   {
-    CDOList values = revision.getList(getFeature());
-
-    int idx = 0;
-    for (Object element : values)
+    CDOList values = revision.getListOrNull(getFeature());
+    if (values != null)
     {
-      writeValue(accessor, revision, idx++, element);
+      int idx = 0;
+      for (Object element : values)
+      {
+        writeValue(accessor, revision, idx++, element);
+      }
     }
   }
 
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractHorizontalClassMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractHorizontalClassMapping.java
index cb0d7519f7..f885e7a5d4 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractHorizontalClassMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractHorizontalClassMapping.java
@@ -70,8 +70,6 @@ import org.eclipse.emf.ecore.EReference;
 import org.eclipse.emf.ecore.EStructuralFeature;
 import org.eclipse.emf.ecore.util.FeatureMapUtil;
 
-import org.eclipse.core.runtime.Assert;
-
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
@@ -91,6 +89,8 @@ import java.util.Set;
  */
 public abstract class AbstractHorizontalClassMapping implements IClassMapping, IMappingConstants, IDeactivateable
 {
+  protected static final int UNSET_LIST = -1;
+
   private static final ContextTracer TRACER = new ContextTracer(OM.DEBUG, AbstractHorizontalClassMapping.class);
 
   private EClass eClass;
@@ -455,19 +455,19 @@ public abstract class AbstractHorizontalClassMapping implements IClassMapping, I
           {
             EStructuralFeature feature = listSizeEntry.getKey();
             IDBField field = listSizeEntry.getValue();
-            int size = resultSet.getInt(field.getName());
 
-            // ensure the listSize (TODO: remove assertion)
-            CDOList list = revision.getList(feature, size);
-
-            for (int i = 0; i < size; i++)
+            int size = resultSet.getInt(field.getName());
+            if (size == UNSET_LIST)
             {
-              list.add(InternalCDOList.UNINITIALIZED);
+              // Leave the list slot in the revision null.
+              continue;
             }
 
-            if (list.size() != size)
+            // Ensure the list size.
+            CDOList list = revision.getOrCreateList(feature, size);
+            for (int i = 0; i < size; i++)
             {
-              Assert.isTrue(false);
+              list.add(InternalCDOList.UNINITIALIZED);
             }
           }
         }
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractListTableMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractListTableMapping.java
index 901c0cdfee..07778bef59 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractListTableMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AbstractListTableMapping.java
@@ -233,9 +233,14 @@ public abstract class AbstractListTableMapping extends AbstractBasicListTableMap
 
   public void readValues(IDBStoreAccessor accessor, InternalCDORevision revision, int listChunk)
   {
-    MoveableList<Object> list = revision.getList(getFeature());
+    if (listChunk == 0)
+    {
+      // Nothing to read. Take shortcut.
+      return;
+    }
 
-    if (listChunk == 0 || list.size() == 0)
+    MoveableList<Object> list = revision.getListOrNull(getFeature());
+    if (list == null || list.size() == 0)
     {
       // Nothing to read. Take shortcut.
       return;
@@ -391,12 +396,14 @@ public abstract class AbstractListTableMapping extends AbstractBasicListTableMap
 
   public void writeValues(IDBStoreAccessor accessor, InternalCDORevision revision)
   {
-    CDOList values = revision.getList(getFeature());
-
-    int idx = 0;
-    for (Object element : values)
+    CDOList values = revision.getListOrNull(getFeature());
+    if (values != null)
     {
-      writeValue(accessor, revision, idx++, element);
+      int idx = 0;
+      for (Object element : values)
+      {
+        writeValue(accessor, revision, idx++, element);
+      }
     }
   }
 
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AuditFeatureMapTableMappingWithRanges.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AuditFeatureMapTableMappingWithRanges.java
index 1567dd5a94..77c6a46f0e 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AuditFeatureMapTableMappingWithRanges.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AuditFeatureMapTableMappingWithRanges.java
@@ -389,10 +389,16 @@ public class AuditFeatureMapTableMappingWithRanges extends AbstractBasicListTabl
 
   public void readValues(IDBStoreAccessor accessor, InternalCDORevision revision, int listChunk)
   {
-    MoveableList<Object> list = revision.getList(getFeature());
+    MoveableList<Object> list = revision.getListOrNull(getFeature());
+    if (list == null)
+    {
+      // Nothing to read take shortcut.
+      return;
+    }
+
     if (listChunk == 0 || list.size() == 0)
     {
-      // nothing to read take shortcut
+      // Nothing to read take shortcut.
       return;
     }
 
@@ -553,17 +559,19 @@ public class AuditFeatureMapTableMappingWithRanges extends AbstractBasicListTabl
 
   public void writeValues(IDBStoreAccessor accessor, InternalCDORevision revision)
   {
-    CDOList values = revision.getList(getFeature());
-
-    int idx = 0;
-    for (Object element : values)
+    CDOList values = revision.getListOrNull(getFeature());
+    if (values != null)
     {
-      writeValue(accessor, revision, idx++, element);
-    }
+      int idx = 0;
+      for (Object element : values)
+      {
+        writeValue(accessor, revision, idx++, element);
+      }
 
-    if (TRACER.isEnabled())
-    {
-      TRACER.format("Writing done"); //$NON-NLS-1$
+      if (TRACER.isEnabled())
+      {
+        TRACER.format("Writing done"); //$NON-NLS-1$
+      }
     }
   }
 
@@ -712,7 +720,7 @@ public class AuditFeatureMapTableMappingWithRanges extends AbstractBasicListTabl
     InternalCDORevision originalRevision = (InternalCDORevision)repo.getRevisionManager().getRevision(id, repo.getBranchManager().getMainBranch().getHead(),
         /* chunksize = */0, CDORevision.DEPTH_NONE, true);
 
-    int oldListSize = originalRevision.getList(getFeature()).size();
+    int oldListSize = originalRevision.size(getFeature());
 
     if (TRACER.isEnabled())
     {
@@ -757,7 +765,7 @@ public class AuditFeatureMapTableMappingWithRanges extends AbstractBasicListTabl
       id = this.originalRevision.getID();
       this.oldVersion = oldVersion;
       this.newVersion = newVersion;
-      lastIndex = originalRevision.getList(getFeature()).size() - 1;
+      lastIndex = originalRevision.size(getFeature()) - 1;
       this.timestamp = timestamp;
     }
 
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AuditListTableMappingWithRanges.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AuditListTableMappingWithRanges.java
index a3d6b6720b..ac85dac311 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AuditListTableMappingWithRanges.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/AuditListTableMappingWithRanges.java
@@ -314,10 +314,16 @@ public class AuditListTableMappingWithRanges extends AbstractBasicListTableMappi
 
   public void readValues(IDBStoreAccessor accessor, InternalCDORevision revision, int listChunk)
   {
-    MoveableList<Object> list = revision.getList(getFeature());
+    MoveableList<Object> list = revision.getListOrNull(getFeature());
+    if (list == null)
+    {
+      // Nothing to read take shortcut.
+      return;
+    }
+
     if (listChunk == 0 || list.size() == 0)
     {
-      // nothing to read take shortcut
+      // Nothing to read take shortcut.
       return;
     }
 
@@ -463,17 +469,19 @@ public class AuditListTableMappingWithRanges extends AbstractBasicListTableMappi
 
   public void writeValues(IDBStoreAccessor accessor, InternalCDORevision revision)
   {
-    CDOList values = revision.getList(getFeature());
-
-    int idx = 0;
-    for (Object element : values)
+    CDOList values = revision.getListOrNull(getFeature());
+    if (values != null)
     {
-      writeValue(accessor, revision, idx++, element);
-    }
+      int idx = 0;
+      for (Object element : values)
+      {
+        writeValue(accessor, revision, idx++, element);
+      }
 
-    if (TRACER.isEnabled())
-    {
-      TRACER.format("Writing done"); //$NON-NLS-1$
+      if (TRACER.isEnabled())
+      {
+        TRACER.format("Writing done"); //$NON-NLS-1$
+      }
     }
   }
 
@@ -545,8 +553,8 @@ public class AuditListTableMappingWithRanges extends AbstractBasicListTableMappi
     CDOBranch main = getMappingStrategy().getStore().getRepository().getBranchManager().getMainBranch();
 
     // get revision from cache to find out version number
-    CDORevision revision = getMappingStrategy().getStore().getRepository().getRevisionManager().getRevision(id, main.getHead(),
-        /* chunksize = */0, CDORevision.DEPTH_NONE, true);
+    CDORevision revision = getMappingStrategy().getStore().getRepository().getRevisionManager().getRevision(id, main.getHead(), /* chunksize = */0,
+        CDORevision.DEPTH_NONE, true);
 
     // set cdo_revision_removed for all list items (so we have no NULL values)
     clearList(accessor, id, revision.getVersion(), FINAL_VERSION);
@@ -817,7 +825,7 @@ public class AuditListTableMappingWithRanges extends AbstractBasicListTableMappi
     InternalCDORevision originalRevision = (InternalCDORevision)repo.getRevisionManager().getRevision(id, repo.getBranchManager().getMainBranch().getHead(),
         /* chunksize = */0, CDORevision.DEPTH_NONE, true);
 
-    int oldListSize = originalRevision.getList(getFeature()).size();
+    int oldListSize = originalRevision.size(getFeature());
 
     if (TRACER.isEnabled())
     {
@@ -864,7 +872,7 @@ public class AuditListTableMappingWithRanges extends AbstractBasicListTableMappi
       id = originalRevision.getID();
       this.oldVersion = oldVersion;
       this.newVersion = newVersion;
-      lastIndex = originalRevision.getList(getFeature()).size() - 1;
+      lastIndex = originalRevision.size(getFeature()) - 1;
       lastRemovedIndex = -1;
     }
 
@@ -975,11 +983,6 @@ public class AuditListTableMappingWithRanges extends AbstractBasicListTableMappi
 
     public void visit(CDOUnsetFeatureDelta delta)
     {
-      if (delta.getFeature().isUnsettable())
-      {
-        throw new ImplementationError("Should not be called"); //$NON-NLS-1$
-      }
-
       if (TRACER.isEnabled())
       {
         TRACER.format("Delta Unsetting"); //$NON-NLS-1$
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/BranchingFeatureMapTableMappingWithRanges.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/BranchingFeatureMapTableMappingWithRanges.java
index 8cc6faab63..6a02a748c8 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/BranchingFeatureMapTableMappingWithRanges.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/BranchingFeatureMapTableMappingWithRanges.java
@@ -394,7 +394,13 @@ public class BranchingFeatureMapTableMappingWithRanges extends AbstractBasicList
 
   public void readValues(IDBStoreAccessor accessor, InternalCDORevision revision, int listChunk)
   {
-    MoveableList<Object> list = revision.getList(getFeature());
+    MoveableList<Object> list = revision.getListOrNull(getFeature());
+    if (list == null)
+    {
+      // Nothing to read take shortcut.
+      return;
+    }
+
     int valuesToRead = list.size();
 
     if (listChunk != CDORevision.UNCHUNKED && listChunk < valuesToRead)
@@ -404,7 +410,7 @@ public class BranchingFeatureMapTableMappingWithRanges extends AbstractBasicList
 
     if (valuesToRead == 0)
     {
-      // nothing to read take shortcut
+      // Nothing to read take shortcut.
       return;
     }
 
@@ -680,17 +686,19 @@ public class BranchingFeatureMapTableMappingWithRanges extends AbstractBasicList
 
   public void writeValues(IDBStoreAccessor accessor, InternalCDORevision revision)
   {
-    CDOList values = revision.getList(getFeature());
-
-    int idx = 0;
-    for (Object element : values)
+    CDOList values = revision.getListOrNull(getFeature());
+    if (values != null)
     {
-      writeValue(accessor, revision, idx++, element);
-    }
+      int idx = 0;
+      for (Object element : values)
+      {
+        writeValue(accessor, revision, idx++, element);
+      }
 
-    if (TRACER.isEnabled())
-    {
-      TRACER.format("Writing done"); //$NON-NLS-1$
+      if (TRACER.isEnabled())
+      {
+        TRACER.format("Writing done"); //$NON-NLS-1$
+      }
     }
   }
 
@@ -830,7 +838,7 @@ public class BranchingFeatureMapTableMappingWithRanges extends AbstractBasicList
       TRACER.format("objectDetached {1}", revision); //$NON-NLS-1$
     }
 
-    clearList(accessor, id, branchId, revision.getVersion(), FINAL_VERSION, revision.getList(getFeature()).size() - 1, revised);
+    clearList(accessor, id, branchId, revision.getVersion(), FINAL_VERSION, revision.size(getFeature()) - 1, revised);
   }
 
   @Override
@@ -850,7 +858,7 @@ public class BranchingFeatureMapTableMappingWithRanges extends AbstractBasicList
     }
 
     InternalCDORevision originalRevision = (InternalCDORevision)accessor.getTransaction().getRevision(id);
-    int oldListSize = originalRevision.getList(getFeature()).size();
+    int oldListSize = originalRevision.size(getFeature());
 
     if (TRACER.isEnabled())
     {
@@ -911,7 +919,7 @@ public class BranchingFeatureMapTableMappingWithRanges extends AbstractBasicList
       branchID = targetBranchID;
       this.oldVersion = oldVersion;
       this.newVersion = newVersion;
-      lastIndex = originalRevision.getList(getFeature()).size() - 1;
+      lastIndex = originalRevision.size(getFeature()) - 1;
       this.timestamp = timestamp;
     }
 
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/BranchingListTableMappingWithRanges.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/BranchingListTableMappingWithRanges.java
index 24e18cac26..aac4f79ff2 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/BranchingListTableMappingWithRanges.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/BranchingListTableMappingWithRanges.java
@@ -296,7 +296,13 @@ public class BranchingListTableMappingWithRanges extends AbstractBasicListTableM
 
   public void readValues(IDBStoreAccessor accessor, InternalCDORevision revision, final int listChunk)
   {
-    MoveableList<Object> list = revision.getList(getFeature());
+    MoveableList<Object> list = revision.getListOrNull(getFeature());
+    if (list == null)
+    {
+      // Nothing to read take shortcut.
+      return;
+    }
+
     int valuesToRead = list.size();
     if (listChunk != CDORevision.UNCHUNKED && listChunk < valuesToRead)
     {
@@ -305,7 +311,7 @@ public class BranchingListTableMappingWithRanges extends AbstractBasicListTableM
 
     if (valuesToRead == 0)
     {
-      // nothing to read take shortcut
+      // Nothing to read take shortcut.
       return;
     }
 
@@ -610,17 +616,19 @@ public class BranchingListTableMappingWithRanges extends AbstractBasicListTableM
 
   public void writeValues(IDBStoreAccessor accessor, InternalCDORevision revision)
   {
-    CDOList values = revision.getList(getFeature());
-
-    int idx = 0;
-    for (Object element : values)
+    CDOList values = revision.getListOrNull(getFeature());
+    if (values != null)
     {
-      writeValue(accessor, revision, idx++, element);
-    }
+      int idx = 0;
+      for (Object element : values)
+      {
+        writeValue(accessor, revision, idx++, element);
+      }
 
-    if (TRACER.isEnabled())
-    {
-      TRACER.format("Writing done"); //$NON-NLS-1$
+      if (TRACER.isEnabled())
+      {
+        TRACER.format("Writing done"); //$NON-NLS-1$
+      }
     }
   }
 
@@ -698,7 +706,7 @@ public class BranchingListTableMappingWithRanges extends AbstractBasicListTableM
 
     int branchID = transaction.getBranch().getID();
     int version = revision.getVersion();
-    int lastIndex = revision.getList(getFeature()).size() - 1;
+    int lastIndex = revision.size(getFeature()) - 1;
 
     clearList(accessor, id, branchID, version, FINAL_VERSION, lastIndex);
   }
@@ -720,7 +728,7 @@ public class BranchingListTableMappingWithRanges extends AbstractBasicListTableM
     }
 
     InternalCDORevision originalRevision = (InternalCDORevision)accessor.getTransaction().getRevision(id);
-    int oldListSize = originalRevision.getList(getFeature()).size();
+    int oldListSize = originalRevision.size(getFeature());
 
     if (TRACER.isEnabled())
     {
@@ -784,7 +792,7 @@ public class BranchingListTableMappingWithRanges extends AbstractBasicListTableM
       branchID = targetBranchID;
       this.oldVersion = oldVersion;
       this.newVersion = newVersion;
-      lastIndex = originalRevision.getList(getFeature()).size() - 1;
+      lastIndex = originalRevision.size(getFeature()) - 1;
       lastRemovedIndex = -1;
     }
 
@@ -844,11 +852,6 @@ public class BranchingListTableMappingWithRanges extends AbstractBasicListTableM
 
     public void visit(CDOUnsetFeatureDelta delta)
     {
-      if (delta.getFeature().isUnsettable())
-      {
-        throw new ImplementationError("Should not be called"); //$NON-NLS-1$
-      }
-
       if (TRACER.isEnabled())
       {
         TRACER.format("Delta Unsetting"); //$NON-NLS-1$
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalAuditClassMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalAuditClassMapping.java
index 873c9fe97a..8859f45065 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalAuditClassMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalAuditClassMapping.java
@@ -487,8 +487,9 @@ public class HorizontalAuditClassMapping extends AbstractHorizontalClassMapping
 
         for (EStructuralFeature feature : listSizeFields.keySet())
         {
-          CDOList list = revision.getList(feature);
-          stmt.setInt(column++, list.size());
+          CDOList list = revision.getListOrNull(feature);
+          int size = list == null ? UNSET_LIST : list.size();
+          stmt.setInt(column++, size);
         }
       }
 
@@ -867,16 +868,19 @@ public class HorizontalAuditClassMapping extends AbstractHorizontalClassMapping
         IListMappingUnitSupport listMapping = listMappings[i];
         EStructuralFeature feature = listMapping.getFeature();
 
-        MoveableList<Object> list = revision.getList(feature);
-        int size = list.size();
-        if (size != 0)
+        MoveableList<Object> list = revision.getListOrNull(feature);
+        if (list != null)
         {
-          if (resultSets[i] == null)
+          int size = list.size();
+          if (size != 0)
           {
-            resultSets[i] = listMapping.queryUnitEntries(accessor, idHandler, timeStamp, rootID);
-          }
+            if (resultSets[i] == null)
+            {
+              resultSets[i] = listMapping.queryUnitEntries(accessor, idHandler, timeStamp, rootID);
+            }
 
-          listMapping.readUnitEntries(resultSets[i], idHandler, id, list);
+            listMapping.readUnitEntries(resultSets[i], idHandler, id, list);
+          }
         }
       }
 
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalBranchingClassMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalBranchingClassMapping.java
index f77135abcd..d4d1d36aef 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalBranchingClassMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalBranchingClassMapping.java
@@ -463,8 +463,9 @@ public class HorizontalBranchingClassMapping extends AbstractHorizontalClassMapp
 
         for (EStructuralFeature feature : listSizeFields.keySet())
         {
-          CDOList list = revision.getList(feature);
-          stmt.setInt(column++, list.size());
+          CDOList list = revision.getListOrNull(feature);
+          int size = list == null ? UNSET_LIST : list.size();
+          stmt.setInt(column++, size);
         }
       }
 
diff --git a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalNonAuditClassMapping.java b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalNonAuditClassMapping.java
index 5bf405e926..be80e65c78 100644
--- a/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalNonAuditClassMapping.java
+++ b/plugins/org.eclipse.emf.cdo.server.db/src/org/eclipse/emf/cdo/server/internal/db/mapping/horizontal/HorizontalNonAuditClassMapping.java
@@ -240,8 +240,9 @@ public class HorizontalNonAuditClassMapping extends AbstractHorizontalClassMappi
 
         for (EStructuralFeature feature : listSizeFields.keySet())
         {
-          CDOList list = revision.getList(feature);
-          stmt.setInt(column++, list.size());
+          CDOList list = revision.getListOrNull(feature);
+          int size = list == null ? UNSET_LIST : list.size();
+          stmt.setInt(column++, size);
         }
       }