Change ActiveEntityModifier such that it flattens the delete requests

Then they can be correctly transformed into select statements in the
DraftCancelAttachmentsHandler

Author: lisajulia

cds-feature-attachments/src/main/java/com/sap/cds/feature/attachments/handler/draftservice/ActiveEntityModifier.java

@@ -17,12 +17,20 @@
 import org.slf4j.LoggerFactory;
 
 /**
- * The class is used to modify the following values in a given {@link CqnStructuredTypeRef}:
+ * A CQL modifier that transforms entity references for draft/active entity handling.
+ *
+ * <p>This modifier flattens complex entity references by removing nested references and creating a
+ * new CQN statement for the specified {@code fullEntityName}. It performs the following
+ * transformations:
  *
  * <ul>
- *   <li>{@code isActiveEntity}
- *   <li>{@code fullEntityName}
+ *   <li>Removes nested references and creates a new entity reference for {@code fullEntityName}
+ *   <li>Preserves the filter from the last segment of the original {@link CqnStructuredTypeRef}
+ *   <li>Adds an {@code IsActiveEntity} filter with the specified boolean value
  * </ul>
+ *
+ * <p>This is primarily used in draft service scenarios to transform queries between draft entities
+ * (IsActiveEntity = false) and active entities (IsActiveEntity = true).
  */
 class ActiveEntityModifier implements Modifier {
 
@@ -45,13 +53,27 @@ public CqnStructuredTypeRef ref(CqnStructuredTypeRef original) {
         rootSegment,
         isActiveEntity,
         fullEntityName);
-    rootSegment.id(fullEntityName);
 
-    Modifier modifier = new ActiveEntityModifier(isActiveEntity, fullEntityName);
-    for (RefSegment segment : ref.segments()) {
-      segment.filter(segment.filter().map(filter -> CQL.copy(filter, modifier)).orElse(null));
-    }
-    return ref.build();
+    // Get the filter from the last segment:
+    // Get the last segment with targetSegment, then an Optional<CqnPredicate> with filter()
+    // which is then unwrapped to CqnPredicate or null by orElse(null).
+    CqnPredicate lastSegmentFilter = original.targetSegment().filter().orElse(null);
+
+    // Create an IsActiveEntity filter
+    CqnPredicate isActiveEntityFilter = CQL.get(Drafts.IS_ACTIVE_ENTITY).eq(isActiveEntity);
+
+    // Combine with original filter if it exists
+    CqnPredicate combinedFilter =
+        lastSegmentFilter != null
+            ? CQL.and(lastSegmentFilter, isActiveEntityFilter)
+            : isActiveEntityFilter;
+
+    // Apply any additional modifications (like replacing other IsActiveEntity references)
+    // This calls the comparison() method below for each comparison in the filter
+    CqnPredicate modifiedFilter = CQL.copy(combinedFilter, this);
+
+    // Create a new entity reference with the modified filter
+    return CQL.entity(fullEntityName).filter(modifiedFilter).asRef();
   }
 
   @Override

cds-feature-attachments/src/main/java/com/sap/cds/feature/attachments/handler/draftservice/DraftCancelAttachmentsHandler.java

@@ -108,7 +108,7 @@ private Validator buildDeleteContentValidator(
   // Unfortunately, context.getEvent() does not return a reliable value in this case.
   private boolean isWhereEmpty(DraftCancelEventContext context) {
     System.out.println(context.getCqn().where());
-    return true; // context.getCqn().where().isEmpty();
+    return context.getCqn().where().isEmpty();
   }
 
   // This function checks if the given entity is of type Attachments
@@ -127,16 +127,13 @@ private boolean hasAttachmentAssociations(CdsEntity entity) {
   private List<Attachments> readAttachments(
       DraftCancelEventContext context, CdsStructuredType entity, boolean isActiveEntity) {
     logger.debug(
-        "Reading attachments for entity {} (isActiveEntity={})",
-        entity.getName(),
-        isActiveEntity);
+        "Reading attachments for entity {} (isActiveEntity={})", entity.getName(), isActiveEntity);
     logger.debug("Original CQN: {}", context.getCqn());
-    CqnDelete cqnInactiveEntity =
+    CqnDelete modifiedCQN =
         CQL.copy(
             context.getCqn(), new ActiveEntityModifier(isActiveEntity, entity.getQualifiedName()));
-    logger.debug("Modified CQN: {}", cqnInactiveEntity);
-    return attachmentsReader.readAttachments(
-        context.getModel(), (CdsEntity) entity, cqnInactiveEntity);
+    logger.debug("Modified CQN: {}", modifiedCQN);
+    return attachmentsReader.readAttachments(context.getModel(), (CdsEntity) entity, modifiedCQN);
   }
 
   private List<Attachments> getCondensedActiveAttachments(

cds-feature-attachments/src/test/java/com/sap/cds/feature/attachments/handler/draftservice/ActiveEntityModifierTest.java

@@ -38,21 +38,28 @@ void activeEntityReplacedToTrue() {
   }
 
   @Test
-  void entityNameReplaced() {
+  void entityNameReplacedAndActiveEntity() {
     var select = Select.from(RootTable_.class).where(root -> root.IsActiveEntity().eq(true));
 
     var result = CQL.copy(select, new ActiveEntityModifier(true, RootTable_.CDS_NAME + "_draft"));
 
-    assertThat(result.toString()).contains("{\"ref\":[\"unit.test.TestService.RootTable_draft\"]}");
+    // Expects the entity to have an IsActiveEntity filter in the reference
+    assertThat(result.toString())
+        .contains(
+            "{\"id\":\"unit.test.TestService.RootTable_draft\",\"where\":[{\"ref\":[\"IsActiveEntity\"]},\"=\",{\"val\":true}]}");
   }
 
   @Test
-  void nothingReplaced() {
+  void entityNameNotReplacedAndActiveEntity() {
     var select = Select.from(RootTable_.class).where(root -> root.IsActiveEntity().eq(true));
 
     var result = CQL.copy(select, new ActiveEntityModifier(true, RootTable_.CDS_NAME));
 
-    assertThat(result).hasToString(select.toString());
+    // Expects the entity to have an IsActiveEntity filter in the reference even when entity name
+    // doesn't change
+    assertThat(result.toString())
+        .contains(
+            "{\"id\":\"unit.test.TestService.RootTable\",\"where\":[{\"ref\":[\"IsActiveEntity\"]},\"=\",{\"val\":true}]}");
   }
 
   @Test
@@ -95,4 +102,27 @@ void onlyRefActiveEntityIsReplaced() {
     assertThat(result.toString()).contains("{\"val\":false},\"=\",{\"ref\":[\"IsActiveEntity\"]}");
     assertThat(result.toString()).contains("{\"val\":true},\"=\",{\"ref\":[\"HasActiveEntity\"]}");
   }
+
+  @Test
+  void combinesNonIsActiveEntityFilterWithIsActiveEntityFilter() {
+    // Create query with a filter on the last/target segment
+    CqnSelect original =
+        Select.from(
+            CQL.entity(RootTable_.CDS_NAME)
+                .filter(CQL.get("title").eq("Some Title")) // Filter on entity reference
+            );
+
+    ActiveEntityModifier modifier = new ActiveEntityModifier(true, RootTable_.CDS_NAME);
+
+    var result = CQL.copy(original, modifier);
+
+    // Should contain both the original title filter and IsActiveEntity filter
+    assertThat(result.toString()).contains("\"title\"");
+    assertThat(result.toString()).contains("\"Some Title\"");
+    assertThat(result.toString()).contains("\"IsActiveEntity\"");
+    assertThat(result.toString()).contains("\"val\":true");
+
+    // The key assertion: should contain AND operation combining both filters
+    assertThat(result.toString()).contains("\"and\"");
+  }
 }

cds-feature-attachments/src/test/java/com/sap/cds/feature/attachments/handler/draftservice/DraftCancelAttachmentsHandlerTest.java

@@ -109,8 +109,11 @@ void attachmentReaderCorrectCalled() {
     CdsEntity target = eventContext.getTarget();
     verify(attachmentsReader)
         .readAttachments(eq(runtime.getCdsModel()), eq(target), deleteArgumentCaptor.capture());
-    CqnDelete originDelete = deleteArgumentCaptor.getValue();
-    assertThat(originDelete.toJson()).isEqualTo(delete.toJson());
+    // Check if the modified CqnDelete that is passed to readAttachments looks correct
+    CqnDelete modifiedCQN = deleteArgumentCaptor.getValue();
+    assertThat(modifiedCQN.toJson())
+        .isEqualTo(
+            "{\"DELETE\":{\"from\":{\"ref\":[{\"id\":\"unit.test.TestService.Attachment\",\"where\":[{\"ref\":[\"IsActiveEntity\"]},\"=\",{\"val\":true}]}]}}}");
 
     deleteArgumentCaptor = ArgumentCaptor.forClass(CqnDelete.class);
     CdsEntity siblingTarget = target.getTargetOf(Drafts.SIBLING_ENTITY);
@@ -133,8 +136,11 @@ void attachmentReaderCorrectCalledForEntityWithAttachmentAssociations() {
     CdsEntity target = eventContext.getTarget();
     verify(attachmentsReader)
         .readAttachments(eq(runtime.getCdsModel()), eq(target), deleteArgumentCaptor.capture());
-    CqnDelete originDelete = deleteArgumentCaptor.getValue();
-    assertThat(originDelete.toJson()).isEqualTo(delete.toJson());
+    // Check if the modified CqnDelete that is passed to readAttachments looks correct
+    CqnDelete modifiedCQN = deleteArgumentCaptor.getValue();
+    assertThat(modifiedCQN.toJson())
+        .isEqualTo(
+            "{\"DELETE\":{\"from\":{\"ref\":[{\"id\":\"unit.test.TestService.RootTable\",\"where\":[{\"ref\":[\"IsActiveEntity\"]},\"=\",{\"val\":true}]}]}}}");
 
     deleteArgumentCaptor = ArgumentCaptor.forClass(CqnDelete.class);
     CdsEntity siblingTarget = target.getTargetOf(Drafts.SIBLING_ENTITY);
@@ -162,7 +168,9 @@ void modifierCalledWithCorrectEntitiesIfDraftIsInContext() {
         .readAttachments(
             eq(runtime.getCdsModel()), eq(siblingTarget), deleteArgumentCaptor.capture());
     CqnDelete siblingDelete = deleteArgumentCaptor.getValue();
-    assertThat(siblingDelete.toJson()).isEqualTo(delete.toJson());
+    assertThat(siblingDelete.toJson())
+        .isEqualTo(
+            "{\"DELETE\":{\"from\":{\"ref\":[{\"id\":\"unit.test.TestService.Attachment\",\"where\":[{\"ref\":[\"IsActiveEntity\"]},\"=\",{\"val\":true}]}]}}}");
   }
 
   @Test