Sergei Zhirikov created IVY-1618:
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Summary: ResolveEngine resets dictator resolver to null in the
global configuration
Key: IVY-1618
URL: https://issues.apache.org/jira/browse/IVY-1618
Project: Ivy
Issue Type: Bug
Components: Core
Affects Versions: 2.5.0
Environment: Windows 10, Java 8, Ivy 2.5.0.
Reporter: Sergei Zhirikov
ResolveEngine does not initialize its dictatorResover field in the constructor.
As the result, when
{code:java}
public ResolveReport resolve(ModuleDescriptor md, ResolveOptions options){code}
is called, the {{oldDictator}} local variable will be set to null in the
beginning of the method. Then, in the end of the same method, inside the
{{finally}} block, {{setDictatorResolver(null)}} will be called, which will not
only set the private field in the ResolveEngine itself, but will also reset the
dictator resolver in the global configuration. Why would it do that???
The problem manifests itself when an {{Ivy}} instance is configured (using Java
API) with only a dictator resolver, it will be able to handle a single call to
{{resolve(...)}} successfully, and all subsequent calls will fail because of
"no resolver available" (because the one that is supposed to be available, has
been reset by the ResolveEngine, as described above).
I have to admit that I am not very familiar with Ivy internals, but I find it
extremely puzzling that an object that is a part of the internal implementation
would change the global configuration at will.
Looking at the implementation of {{Ivy}} and {{IvyContext}} classes, I get the
impression that an {{Ivy}} instance is supposed to be thread-safe, in the sense
that it should allow to call {{resolve(...)}} on the same instance from
multiple threads safely. Am I mistaken? If there is supposed to be any thread
safety, it is broken by the peculiar behavior of ResolveEngine with respect to
setting the dictator resolver.
In any case, I think it would be really helpful to explicitly mention thread
safety (or lack thereof) in the Javadoc page of the main {{Ivy}} class.
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