[IBATISNET-232] Nested left joins with group by cause NPE when two subsequent levels have null values

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: DataMapper 1.6.1
• Fix Version/s: DataMapper 1.6.2
• Component/s: DataMapper
• Assignee: Gilles Bayon
• Reporter: Spyros Oikonomopoulos
• Created: 19/Jul/07 07:42
• Updated: 15/Sep/07 14:29
• Resolved: 15/Sep/07 14:29

Description

Region (region_id, name) values: (1, 'reg1') (2, 'reg2')
State (state_id, region_id, name) values: (1, 1, 'state1')
City (city_id, region_id, state_id, name) values (1,1,1,'city1')

A nested group with left joins will create the following rows:

1 reg1 — 1 1 state 1 — 1 1 1 city1
2 reg2 — null — null

Now during construction of the object hierarchy iBatis, for the second row tries to set the "cities" collection of the state object, which unfortunately is null, so an NPE is raised.