Hibernate version: Latest from the SVN repository trunk (revision 2927)
Hi,
I am using the latest development version from the trunk, but I assume the problem affects 1.2 version as well.
Enabling query-cache on a projection query with a result transformer attached using Criteria API, will fail with an exception:
"System.InvalidCastException: Unable to cast object of type '<The output type from the result transformer' to type 'System.Object[]'"
The exception is caused by the line:
Code:
cacheable.Add( TypeFactory.Disassemble( ( object[ ] ) result[ i ], returnTypes, session ) );
in "NHibernate\Cache\StandardQueryCache.cs" on line 63, when it tries to cast the "result[i]" to an "object[]".
Using result transformers the result set has already been transformed to the transformed type, before adding to the cache, so casting to "object[]" will fail. (The transformation is done in the method "GetResultColumnOrRow" in CriteriaLoader.cs on line 74, which gets called in process of loading the result set from the database).
To reproduce the issue, turn on caching on any of the projection query tests with result transformer in "CriteriaQueryTests.cs". E.g. on line 494
Code:
IList resultWithAliasedBean = s.CreateCriteria(typeof (Enrolment))
.CreateAlias("Student", "st")
.CreateAlias("Course", "co")
.SetProjection(Projections.ProjectionList()
.Add(Projections.Property("st.Name"), "studentName")
.Add(Projections.Property("co.Description"), "courseDescription")
)
.AddOrder(Order.Desc("studentName"))
.SetResultTransformer(Transformers.AliasToBean(typeof (StudentDTO)))
.SetCacheable(true)
.List();
I am not sure if this is by design or a bug, but I though I'd report it anyway. At least I didn't find anything in the documentation implying that query cache shouldn't work in this situation.
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