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Scott Wegner commented on BEAM-308: ----------------------------------- PR with failing test cases: https://github.com/apache/incubator-beam/pull/389/files /cc [~bchambers] [~lcwik] > PipelineOptions throws when using package-private PipelineOptions interfaces > from multiple packages > --------------------------------------------------------------------------------------------------- > > Key: BEAM-308 > URL: https://issues.apache.org/jira/browse/BEAM-308 > Project: Beam > Issue Type: Bug > Components: sdk-java-core > Reporter: Scott Wegner > Assignee: Scott Wegner > Priority: Minor > > If a PipelineOptions instance is used as multiple PipelineOptions > package-private interfaces from different packages, {{PipelineOptions.as}} > will throw an exception: > {quote} > java.lang.IllegalArgumentException: non-public interfaces from different > packages > at java.lang.reflect.Proxy$ProxyClassFactory.apply(Proxy.java:652) > at java.lang.reflect.Proxy$ProxyClassFactory.apply(Proxy.java:592) > at java.lang.reflect.WeakCache$Factory.get(WeakCache.java:244) > at java.lang.reflect.WeakCache.get(WeakCache.java:141) > at java.lang.reflect.Proxy.getProxyClass0(Proxy.java:455) > at java.lang.reflect.Proxy.getProxyClass(Proxy.java:405) > at > org.apache.beam.sdk.options.PipelineOptionsFactory.validateWellFormed(PipelineOptionsFactory.java:620) > at > org.apache.beam.sdk.options.ProxyInvocationHandler.as(ProxyInvocationHandler.java:209) > at > org.apache.beam.sdk.options.ProxyInvocationHandler.invoke(ProxyInvocationHandler.java:135) > at com.sun.proxy.$Proxy6.as(Unknown Source) > {quote} > This fails because ProxyInvocationHandler attempts to create a Java Proxy > object implementing the full set of interfaces, which has the > [restriction|https://docs.oracle.com/javase/7/docs/api/java/lang/reflect/Proxy.html#getProxyClass(java.lang.ClassLoader,%20java.lang.Class...)]: > > bq. All non-public interfaces must be in the same package; otherwise, it > would not be possible for the proxy class to implement all of the interfaces, > regardless of what package it is defined in. > This can be triggered in a couple edge-case scenarios: > # {{PipelineOptions.as}} is called on the same PipelineOptions instance with > multiple package-private interfaces. > # {{PipelineOptionsFactory.register}} is called with a package-private > interface, and then {{PipelineOptions.as}} is called with a different > package-private instance. > We hit the second scenario in [DataflowSDK unit > tests|https://github.com/GoogleCloudPlatform/DataflowJavaSDK/pull/286#issuecomment-221438063]. > It's hard to trigger, but possible. > ---- > I propose we make the behavior for package-private options explicit: > # Give a better exception message if we hit this issue in > {{PipelineOptions.as}} listing the non-public interfaces and what packages > they're in. > # Explicitly reject non-public interfaces from > {{PipelineOptionsFactory.register}}, since this state is global and is easier > to cause issues. -- This message was sent by Atlassian JIRA (v6.3.4#6332)