Entity graphs containing bi-directional references may not merge correctly if
an entity does not contain a state manager
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Key: OPENJPA-1966
URL: https://issues.apache.org/jira/browse/OPENJPA-1966
Project: OpenJPA
Issue Type: Bug
Components: kernel
Affects Versions: 2.1.0, 2.0.1, 1.2.2, 1.0.4
Reporter: Jeremy Bauer
Assignee: Jeremy Bauer
An entity graph (with cascade) containing bi-directional relationships or
circular references may fail to merge properly if one or more of the entities
in the graph do not have a state manager - either an active or detached state
manager. The result is that one or more of the merged entities may end up with
a reference to a detached object. This may not be immediately evident and
could cause problems in subsequent operations. It can even affect the ordering
of SQL statements since foreign keys may not be properly associated with the
detached entities.
For example: A <- OneToOne -> B
em.clear()
Detached graph: B <--> A
A: Is detached, has DetachedStateManager
B: Is detached, No state manager, only detached state field. (ie.
@DetachedState Object state)
Merge: B
After merge: B' --> A' --> B (detached)
If B contains a state manager the result of the merge is correct: B' <--> A'
The source of the problem is that the "no state manager" attachment path
creates a new PC + state manager and assigns this state manager to the detached
instance so that it can be used to attach all its fields. During a cascade,
this detached entity (with borrowed state manager) looks persistent, so it can
get attached into the resulting merge graph.
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