[jira] Updated: (FELIX-1422) Resolver does not always discard partial results when a cyclically dependency fails

["Richard S. Hall (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FELIX-1422?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Richard S. Hall updated FELIX-1422:
-----------------------------------

    Description: 
When resolving dependencies among bundles, if a cycle is detected the resolver algorithm assumes the resolve is successful. So, assuming we want to resolve A and A wants to import from B and B wants to import from A, we end up building up a data structure where A has B as a potential candidate and B has A. If A is unable to resolve, then the whole thing fails and everything is fine. However, if the resolve starts with C and C has an optional import from A, then when A fails to resolve it is ignored since it was optional for C. This means the partial resolve results for A will be discarded, but unfortunately the partial resolve results for B are not. This means if C also has a dependency on B, the partial resolve results will be used as if they were correct, even though they include A as a candidate, which could not be resolved. The end result is an NPE when creating wires, since it tries to create a wire to an unresolved bundle.

We need to remove assumptions we made about cycles if they ultimately fail to resolve.

  was:
When resolving dependencies among bundles, if a cycle is detected the resolver algorithm assumes the resolve is successful. So, assuming we want to resolve A and A wants to import from B and B wants to import from A, we end up building up a data structure where A has B as a potential candidate and B has A. If A is unable to resolve, then the whole thing fails and everything is fine. However, if the resolve starts with C and C has an optional import from A, then when A fails to resolve it is ignored since it was optional for C. This means the partial resolve results for A will be discarded, but unfortunately the partial resolve results for B are not. This means if C also has a dependency on B, the partial resolve results will be used as if they were correct, even though they include A as a candidate, which could not be resolved. The end result is an improper resolve result.

We need to remove assumptions we made about cycles if they ultimately fail to resolve.


> Resolver does not always discard partial results when a cyclically dependency fails
> -----------------------------------------------------------------------------------
>
>                 Key: FELIX-1422
>                 URL: https://issues.apache.org/jira/browse/FELIX-1422
>             Project: Felix
>          Issue Type: Bug
>          Components: Framework, Specification compliance
>    Affects Versions: felix-1.8.1
>            Reporter: Richard S. Hall
>            Assignee: Richard S. Hall
>            Priority: Minor
>             Fix For: felix-2.0.0
>
>
> When resolving dependencies among bundles, if a cycle is detected the resolver algorithm assumes the resolve is successful. So, assuming we want to resolve A and A wants to import from B and B wants to import from A, we end up building up a data structure where A has B as a potential candidate and B has A. If A is unable to resolve, then the whole thing fails and everything is fine. However, if the resolve starts with C and C has an optional import from A, then when A fails to resolve it is ignored since it was optional for C. This means the partial resolve results for A will be discarded, but unfortunately the partial resolve results for B are not. This means if C also has a dependency on B, the partial resolve results will be used as if they were correct, even though they include A as a candidate, which could not be resolved. The end result is an NPE when creating wires, since it tries to create a wire to an unresolved bundle.
> We need to remove assumptions we made about cycles if they ultimately fail to resolve.

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