[533944] CDOServerExporter and Importer don't handle unsettable lists correctly

https://bugs.eclipse.org/bugs/show_bug.cgi?id=533944

2 files changed, 37 insertions, 8 deletions

diff --git a/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/CDOServerExporter.java b/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/CDOServerExporter.java
index db592ee4c1..5ac6a618c3 100644
--- a/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/CDOServerExporter.java
+++ b/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/CDOServerExporter.java
@@ -336,6 +336,11 @@ public abstract class CDOServerExporter<OUT>
 
     public static final String FEATURE_VALUE = "value";
 
+    /**
+     * @since 4.7
+     */
+    public static final String FEATURE_ISSET = "isset";
+
     public static final String FEATURE_ID = "id";
 
     public static final String FEATURE_SIZE = "size";
@@ -524,13 +529,19 @@ public abstract class CDOServerExporter<OUT>
         {
           @SuppressWarnings("unchecked")
           List<Object> list = (List<Object>)rev.getValue(feature);
-          if (list != null)
+          if (list != null && !list.isEmpty())
           {
             for (Object value : list)
             {
               exportFeature(out, feature, value);
             }
           }
+          else if (feature.isUnsettable())
+          {
+            out.element(FEATURE);
+            out.attribute(FEATURE_NAME, feature.getName());
+            out.attribute(FEATURE_ISSET, list != null);
+          }
         }
         else
         {
diff --git a/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/CDOServerImporter.java b/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/CDOServerImporter.java
index 257ae86235..c971760930 100644
--- a/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/CDOServerImporter.java
+++ b/plugins/org.eclipse.emf.cdo.server/src/org/eclipse/emf/cdo/server/CDOServerImporter.java
@@ -451,8 +451,6 @@ public abstract class CDOServerImporter
         else if (FEATURE.equals(qName))
         {
           String name = attributes.getValue(FEATURE_NAME);
-          Object value = value(attributes);
-
           EClass eClass = revision.getEClass();
           EStructuralFeature feature = eClass.getEStructuralFeature(name);
           if (feature == null)
@@ -460,16 +458,36 @@ public abstract class CDOServerImporter
             throw new IllegalStateException("Feature " + name + " not found in class " + eClass.getName());
           }
 
-          if (feature.isMany())
+          String isSetString = attributes.getValue(FEATURE_ISSET);
+          if (isSetString != null)
           {
-            CDOList list = revision.getOrCreateList(feature);
-            list.add(value);
+            // This must be an empty or an unset list.
+            boolean isSet = Boolean.parseBoolean(isSetString);
+            if (isSet)
+            {
+              // Create an empty list.
+              revision.getOrCreateList(feature);
+            }
+            else
+            {
+              // Leave the list unset.
+            }
           }
           else
           {
-            if (value != null)
+            Object value = value(attributes);
+
+            if (feature.isMany())
+            {
+              CDOList list = revision.getOrCreateList(feature);
+              list.add(value);
+            }
+            else
             {
-              revision.setValue(feature, value);
+              if (value != null)
+              {
+                revision.setValue(feature, value);
+              }
             }
           }
         }