CAY-2911 Column Select Sometimes Null With Vertically Inherited Entity

Author: m-dzianishchyts

cayenne/src/main/java/org/apache/cayenne/access/jdbc/reader/EntityRowReader.java

@@ -54,7 +54,7 @@ class EntityRowReader implements RowReader<DataRow> {
             this.entityName = classDescriptor.getEntity().getName();
         }
 
-        int segmentWidth = segmentMetadata.getFields().size();
+        int segmentWidth = segmentMetadata.getColumnCount();
         this.startIndex = segmentMetadata.getColumnOffset();
         this.converters = new ExtendedType[segmentWidth];
         this.types = new int[segmentWidth];

cayenne/src/main/java/org/apache/cayenne/access/translator/select/DescriptorColumnExtractor.java

@@ -151,8 +151,10 @@ public boolean visitToOne(ToOneProperty property) {
 
         int count = result.getDbAttributes().size();
         for(int i=0; i<count; i++) {
-            processTranslationResult(result, i);
-            addEntityResultField(result.getDbAttributes().get(i));
+            ResultNodeDescriptor resultNodeDescriptor = processTranslationResult(result, i);
+            if(resultNodeDescriptor != null) {
+                addEntityResultField(result.getDbAttributes().get(i));
+            }
         }
 
         return true;

cayenne/src/main/java/org/apache/cayenne/ejbql/parser/Compiler.java

@@ -291,9 +291,8 @@ public boolean visitToOne(ToOneProperty property) {
 
         // append inheritance discriminator columns...
         for (ObjAttribute column : descriptor.getDiscriminatorColumns()) {
-
-            if (visited.add(column.getName())) {
-                String dbAttributePath = column.getDbAttributePath().value();
+            String dbAttributePath = column.getDbAttributePath().value();
+            if (visited.add(dbAttributePath)) {
                 compiledResult.addDbField(
                         "fetch." + prefix + "." + dbAttributePath,
                         prefix + "." + dbAttributePath);
@@ -363,8 +362,9 @@ public boolean visitToOne(ToOneProperty property) {
 
         // append inheritance discriminator columns...
         for (ObjAttribute column : descriptor.getDiscriminatorColumns()) {
-            if (visited.add(column.getName())) {
-                entityResult.addDbField(column.getDbAttributePath().value(), prefix + index[0]++);
+            String dbAttributePath = column.getDbAttributePath().value();
+            if (visited.add(dbAttributePath)) {
+                entityResult.addDbField(dbAttributePath, prefix + index[0]++);
             }
         }
 

cayenne/src/main/java/org/apache/cayenne/map/DefaultEntityResultSegment.java

@@ -31,12 +31,19 @@ public class DefaultEntityResultSegment implements EntityResultSegment {
     private ClassDescriptor classDescriptor;
     private Map<String, String> fields;
     private int offset;
+    private int columnCount;
 
     public DefaultEntityResultSegment(ClassDescriptor classDescriptor,
             Map<String, String> fields, int offset) {
+        this(classDescriptor, fields, offset, fields != null ? fields.size() : 0);
+    }
+
+    public DefaultEntityResultSegment(ClassDescriptor classDescriptor,
+            Map<String, String> fields, int offset, int columnCount) {
         this.classDescriptor = classDescriptor;
         this.fields = fields;
         this.offset = offset;
+        this.columnCount = columnCount;
     }
 
     public ClassDescriptor getClassDescriptor() {
@@ -47,6 +54,11 @@ public Map<String, String> getFields() {
         return fields;
     }
 
+    @Override
+    public int getColumnCount() {
+        return columnCount;
+    }
+
     public int getColumnOffset() {
         return offset;
     }

cayenne/src/main/java/org/apache/cayenne/map/EntityResult.java

@@ -75,6 +75,13 @@ public Map<String, String> getDbFields(EntityResolver resolver) {
         return dbFields;
     }
 
+    /**
+     * Returns the total number of fields added to this result.
+     */
+    public int getFieldCount() {
+        return fields != null ? fields.size() : 0;
+    }
+
     private ObjEntity getRootEntity(EntityResolver resolver) {
         if (entityName != null) {
             return resolver.getObjEntity(entityName);

cayenne/src/main/java/org/apache/cayenne/map/SQLResult.java

@@ -61,15 +61,16 @@ public List<Object> getResolvedComponents(EntityResolver resolver) {
             } else if (component instanceof EntityResult) {
                 EntityResult entityResult = (EntityResult) component;
                 Map<String, String> fields = entityResult.getDbFields(resolver);
+                int columnCount = entityResult.getFieldCount();
 
                 String entityName = entityResult.getEntityName();
                 if (entityName == null) {
                     entityName = resolver.getObjEntity(entityResult.getEntityClass()).getName();
                 }
 
                 ClassDescriptor classDescriptor = resolver.getClassDescriptor(entityName);
-                resolvedComponents.add(new DefaultEntityResultSegment(classDescriptor, fields, offset));
-                offset = offset + fields.size();
+                resolvedComponents.add(new DefaultEntityResultSegment(classDescriptor, fields, offset, columnCount));
+                offset = offset + columnCount;
             } else if (component instanceof EmbeddedResult) {
                 EmbeddedResult embeddedResult = (EmbeddedResult)component;
                 Map<String, String> fields = embeddedResult.getFields();

cayenne/src/main/java/org/apache/cayenne/query/EntityResultSegment.java

@@ -39,6 +39,11 @@ public interface EntityResultSegment {
      */
     Map<String, String> getFields();
 
+    /**
+     * Returns the total number of columns in this segment.
+     */
+    int getColumnCount();
+
     /**
      * Performs a reverse lookup of the column path for a given ResultSet label.
      */

cayenne/src/main/java/org/apache/cayenne/reflect/PersistentDescriptorResultMetadata.java

@@ -52,6 +52,11 @@ public String getColumnPath(String resultSetLabel) {
 		return reverseFields.get(resultSetLabel);
 	}
 
+	@Override
+	public int getColumnCount() {
+		return fields.size();
+	}
+
 	void addObjectField(String attributeName, String column) {
 		ObjEntity entity = classDescriptor.getEntity();
 

cayenne/src/test/java/org/apache/cayenne/access/VerticalInheritanceIT.java

@@ -22,6 +22,7 @@
 import org.apache.cayenne.ObjectContext;
 import org.apache.cayenne.Persistent;
 import org.apache.cayenne.di.Inject;
+import org.apache.cayenne.exp.ExpressionFactory;
 import org.apache.cayenne.query.ColumnSelect;
 import org.apache.cayenne.query.EJBQLQuery;
 import org.apache.cayenne.query.ObjectSelect;
@@ -727,6 +728,55 @@ public void testUpdateFlattenedRelationshipWithInverse() throws SQLException {
 		}
 	}
 
+	@Test
+	public void testColumnQueryVerticallyInheritedToVerticallyInherited() throws SQLException {
+        TableHelper ivDocumentTable = new TableHelper(dbHelper, "IV_DOCUMENT");
+        ivDocumentTable.setColumns("ID", "TYPE").setColumnTypes(Types.INTEGER, Types.CHAR);
+
+        TableHelper ivDocumentLineTable = new TableHelper(dbHelper, "IV_DOCUMENT_LINE");
+        ivDocumentLineTable.setColumns("ID", "TYPE", "DOCUMENT_ID").setColumnTypes(Types.INTEGER, Types.CHAR, Types.INTEGER);
+
+        TableHelper IvDocumentATable = new TableHelper(dbHelper, "IV_DOCUMENT_A");
+        IvDocumentATable.setColumns("ID").setColumnTypes(Types.INTEGER);
+
+        TableHelper IvDocumentALineTable = new TableHelper(dbHelper, "IV_DOCUMENT_A_LINE");
+        IvDocumentALineTable.setColumns("ID").setColumnTypes(Types.INTEGER);
+
+        TableHelper IvDocumentBTable = new TableHelper(dbHelper, "IV_DOCUMENT_B");
+        IvDocumentBTable.setColumns("ID", "RELATED_A_ID").setColumnTypes(Types.INTEGER, Types.INTEGER);
+
+        TableHelper IvDocumentBLineTable = new TableHelper(dbHelper, "IV_DOCUMENT_B_LINE");
+        IvDocumentBLineTable.setColumns("ID").setColumnTypes(Types.INTEGER);
+
+        int documentAId = 1;
+        ivDocumentTable.insert(documentAId, "A");
+        IvDocumentATable.insert(documentAId);
+
+        int documentALineId = 2;
+        ivDocumentLineTable.insert(documentALineId, "A", documentAId);
+        IvDocumentALineTable.insert(documentALineId);
+
+        int documentBId = 3;
+        ivDocumentTable.insert(documentBId, "B");
+        IvDocumentBTable.insert(documentBId, documentAId);
+
+        int documentBLineId = 4;
+        ivDocumentLineTable.insert(documentBLineId, "B", documentBId);
+        IvDocumentBLineTable.insert(documentBLineId);
+
+        {
+            ObjectContext newContext = runtime.newContext();
+
+            IvDocument documentA = ObjectSelect.query(IvDocumentALine.class).where(ExpressionFactory.matchDbIdExp("ID", documentALineId)).column(IvDocumentALine.DOCUMENT).selectOne(newContext);
+            assertNotNull(documentA);
+            assertEquals(IvDocumentA.class, documentA.getClass());
+
+            IvDocument documentB = ObjectSelect.query(IvDocumentBLine.class).where(ExpressionFactory.matchDbIdExp("ID", documentBLineId)).column(IvDocumentBLine.DOCUMENT).selectOne(newContext);
+            assertNotNull(documentB);
+            assertEquals(IvDocumentB.class, documentB.getClass());
+        }
+	}
+
 	@Test
 	public void testDeleteFlattenedNoValues() throws SQLException {
 		ivAbstractTable.insert(1, null, "S");
@@ -1188,6 +1238,7 @@ public void testColumnSelectVerticalInheritance_Sub1() throws SQLException {
 	}
 
 	@Test
+//	@Ignore("Address CAY-2911")
 	public void testColumnSelectVerticalInheritance_Sub1Sub1() throws SQLException {
 		TableHelper ivRootTable = new TableHelper(dbHelper, "IV_ROOT");
 		ivRootTable.setColumns("ID", "NAME", "DISCRIMINATOR");

cayenne/src/test/java/org/apache/cayenne/testdo/inheritance_vertical/IvDocument.java

@@ -0,0 +1,10 @@
+package org.apache.cayenne.testdo.inheritance_vertical;
+
+
+import org.apache.cayenne.testdo.inheritance_vertical.auto._IvDocument;
+
+public abstract class IvDocument extends _IvDocument {
+
+    private static final long serialVersionUID = 1L;
+
+}