Thomas Watson created ARIES-1554:
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Summary: FelixResourceAdapter returns true for resources of other
types
Key: ARIES-1554
URL: https://issues.apache.org/jira/browse/ARIES-1554
Project: Aries
Issue Type: Bug
Components: Subsystem
Environment: All
Reporter: Thomas Watson
Assignee: Thomas Watson
The Resource implementation
org.apache.aries.subsystem.util.felix.FelixResourceAdapter does an equality
check based on the osgi.identity name, version, and type. This typically is
not an issue but the contract for Resource.equals states the following:
<javadoc>
This Resource is equal to another Resource if both have the same content and
come from the same location. Location may be defined as the bundle location if
the resource is an installed bundle or the repository location if the resource
is in a repository.
</javadoc>
The assumption is that if the osgi.identity name, version and type are equal
then the resources have the "same content". But the implementation does not
take into account the location. This causes issues if resources are used as
keys in a Map and the Map will contain resources of different implementation
types. This is done by the felix resolver implementation. In some scenarios
the subsystems will return to the resolver resources from the OBR repository
and from the system repository (installed bundles) that have the same name,
version, type. From the resolver's perspective these two resources must be
treated as distinctly different resources because they come from completely
different locations. And the framework's Resource implementation of equals
does return false if checked against a FelixResourceAdapter, but the
FelixResourceAdapter equals method will return true if check against the
framework's Resource implementation. This inconsistency in the equals behavior
reeks havoc for Map implementations. Usually the issue is very intermittent
because of they way hash slots are determined based on hashcodes, but in rare
cases these two resources will be slotted the same and collide with eachother
depending on the Map implementation.
At a minimum the FelixResourceAdapter should check that the other object is an
instance of FelixResourceAdapter to be able to return true. This makes the
simple assumption that if the Resource is not of type FelixResourceAdapter then
there is no way the resource is at the same location.
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