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Posted to dev@felix.apache.org by "matteo rulli (JIRA)" <ji...@apache.org> on 2016/10/26 19:44:58 UTC

[jira] [Created] (FELIX-5389) NullPointerException in Candidates#prepare() method

matteo rulli created FELIX-5389:
-----------------------------------

             Summary: NullPointerException in Candidates#prepare() method
                 Key: FELIX-5389
                 URL: https://issues.apache.org/jira/browse/FELIX-5389
             Project: Felix
          Issue Type: Bug
          Components: Resolver
    Affects Versions: resolver-1.10.0
            Reporter: matteo rulli


Project where the errors appear: https://github.com/mrulli/com.flairbit.eclipsecon.onesix

----
During the resolution of my bundles I get the following stacktrace (to trigger the resolution, just do {{mvn install}} from the {{example.cassandra.itest.bndrun}} folder in the project above):

{code}
[ERROR] Failed to execute goal biz.aQute.bnd:bnd-export-maven-plugin:3.4.0-SNAPSHOT:export (default) on project example.cassandra.bndrun: null: MojoExecutionException: NullPointerException -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal biz.aQute.bnd:bnd-export-maven-plugin:3.4.0-SNAPSHOT:export (default) on project example.cassandra.bndrun: null
 at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:216)
 at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
 at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
 at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:116)
 at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:80)
 at org.apache.maven.lifecycle.internal.builder.singlethreaded.SingleThreadedBuilder.build(SingleThreadedBuilder.java:51)
 at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:120)
 at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:347)
 at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:154)
 at org.apache.maven.cli.MavenCli.execute(MavenCli.java:582)
 at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:214)
 at org.apache.maven.cli.MavenCli.main(MavenCli.java:158)
 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
 at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
 at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
 at java.lang.reflect.Method.invoke(Method.java:498)
 at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:289)
 at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:229)
 at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:415)
 at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:356)
Caused by: org.apache.maven.plugin.MojoExecutionException
 at aQute.bnd.maven.export.plugin.ExportMojo.execute(ExportMojo.java:52)
 at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:132)
 at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:208)
 ... 19 more
Caused by: java.lang.NullPointerException
 at org.apache.felix.resolver.Candidates.prepare(Candidates.java:946)
 at org.apache.felix.resolver.ResolverImpl.getInitialCandidates(ResolverImpl.java:502)
 at org.apache.felix.resolver.ResolverImpl.doResolve(ResolverImpl.java:387)
 at org.apache.felix.resolver.ResolverImpl.resolve(ResolverImpl.java:375)
 at org.apache.felix.resolver.ResolverImpl.resolve(ResolverImpl.java:329)
 at biz.aQute.resolve.BndResolver.resolve(BndResolver.java:29)
 at biz.aQute.resolve.ResolveProcess.resolveRequired(ResolveProcess.java:75)
 at biz.aQute.resolve.ProjectResolver.resolve(ProjectResolver.java:109)
 at biz.aQute.resolve.ProjectResolver.getRunBundles(ProjectResolver.java:126)
 at aQute.bnd.maven.export.plugin.ExportMojo.resolve(ExportMojo.java:86)
 at aQute.bnd.maven.export.plugin.ExportMojo.export(ExportMojo.java:70)
 at aQute.bnd.maven.export.plugin.ExportMojo.execute(ExportMojo.java:49)
 ... 21 more
{code}

I tried to investigate a little bit this and I found that the NPE is generated in the {{prepare()}} method - {{org.apache.felix.resolver.Candidates}} class, within the following snippet:
{code}
m_candidateMap.put(r, cands.copy());
for (Capability cand : cands.getRemainingCandidates())
{
    Set<Requirement> dependents = m_dependentMap.get(cand);
    dependents.remove(origReq);
    dependents.add(r);
}
{code}
{{org.apache.felix.resolver.Candidates.m_dependentMap.get}} is invoked with key
{code}
    WrappedCapability: '[slf4j.api version=1.6.1] osgi.wiring.package; org.slf4j.impl' 
        m_cap: Provide[osgi.wiring.package]{version=1.6.1, osgi.wiring.package=org.slf4j.impl}{}
        m_host: slf4j.api version=1.6.1
{code}
and this nullifies {{dependents}} var. The only WrappedCapabilities within the m_dependentMap key set are the followings:
{code}
 [slf4j.api version=1.7.7] osgi.wiring.package; (&(osgi.wiring.package=org.slf4j)(version>=1.6.1))
 [slf4j.api version=1.7.5] osgi.wiring.package; (&(osgi.wiring.package=org.slf4j.spi)(version>=1.6.1))
 [slf4j.api version=1.7.5] osgi.wiring.package; (&(osgi.wiring.package=org.apache.log4j))
 [slf4j.api version=1.6.1] osgi.wiring.package; (&(osgi.wiring.package=org.slf4j.impl)(version>=1.6.0))
 [slf4j.api version=1.7.5] osgi.wiring.package; (&(osgi.wiring.package=org.slf4j.helpers)(version>=1.6.1))
 [slf4j.api version=1.7.7] osgi.wiring.package; (&(osgi.wiring.package=org.apache.log4j))
 [slf4j.api version=1.7.7] osgi.wiring.package; (&(osgi.wiring.package=org.slf4j.helpers)(version>=1.6.1))
 [slf4j.api version=1.7.5] osgi.wiring.package; (&(osgi.wiring.package=org.slf4j.impl)(version>=1.6.0))
 [slf4j.api version=1.7.7] osgi.wiring.package; (&(osgi.wiring.package=org.slf4j.spi)(version>=1.6.1))
 [slf4j.api version=1.7.7] osgi.wiring.package; (&(osgi.wiring.package=org.slf4j.impl)(version>=1.6.0))
 [slf4j.api version=1.7.5] osgi.wiring.package; (&(osgi.wiring.package=org.slf4j)(version>=1.6.1))
{code}
and none of them match the specified key above, at least as long as the WrappedCapability equals method is concerned.
In my opinion a meaningful error should be thrown by the resolver instead of throwing NullPointerException. Or maybe it is just enough to skip actions on dependents in case null value is returned?



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