[CAY-1725] NullPointerException from call to removeToManyTarget

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 3.0.1, 3.0.2
• Fix Version/s: 3.1B2, 3.2.M1, 3.0.3
• Component/s: Core Library
• Assignee: Unassigned
• Reporter: Aaron Andersen
• Created: 12/Jul/12 13:54
• Updated: 13/Jul/12 20:13
• Resolved: 13/Jul/12 20:13

Description

I am using Cayenne version 3.0.1.

In CayenneModeler I have created an "Approver" DbEntity and a "Department" DbEntity (as well as the corresponding ObjEntity classes). I have also created an "Authorization" DbEntity to act as a join table for the Approver and Department tables. Every Approver object has a list of Department objects associated with it, and vice versa so in CayenneModeler I have added a "departmentArray" relationship to the Approver object which has "to many, list" semantics.

When I use the Approver method "void addToDepartmentArray (Department)" everything works fine, but when I use the Approver method "void removeFromDepartmentArray (Department)" (which simple calls removeToManyTarget) a NullPointerException is thrown. A backtrace and quick debug tells me the null pointer exception originates from:

org.apache.cayenne.access.DataDomainFlattenedBucket.addFlattenedDelete(DataDomainFlattenedBucket.java:82)

The code on lines 81 and 82 of this file are as follows:

[81] List flattenedSnapshots = flattenedDeleteInfo.buildJoinSnapshotsForDelete(node);
[82] if (!flattenedSnapshots.isEmpty()) {

Inspecting flattenedSnapshots on line 82 shows that flattenedSnapshots is null hence accessing the isEmpty method is causing the null pointer exception.

I have also tested with Cayenne 3.0.2 and the same error occurs.

Here is a simple code snippet to reproduce this error:

// make sure our context is clear of any changes
context.rollbackChanges ();

// set up a new approver and department
Approver approver = context.newObject (Approver.class);
Department dept = context.newObject (Department.class);

approver.setLogin ("approver");
dept.setName ("departmentA");

// add the department to the approver
approver.addToDepartmentArray (dept);

// commit these to the database, so far everything should be running fine
context.commitChanges ();

// remove the department from the approver...
// this should work fine because we haven't committed yet
approver.removeFromDepartmentArray (dept);

try

{ // this is where things go bad context.commitChanges (); }

catch (Exception e)

{ // error has occurred // at this point the record in the Authorization table still exists }

Issue Links

• is related to: CAY-1689 [PATCH] LOB*QueryBuilders do not check isQuotingSQLIdentifiers