[BEAM-308] PipelineOptions throws when using package-private PipelineOptions interfaces from multiple packages

• Type: Bug
• Status: Resolved
• Priority: P3
• Resolution: Fixed
• Fix Version/s: 2.13.0
• Component/s: sdk-java-core
• Labels: Done backwards-incompatible
• Assignee: Luke Cwik
• Reporter: Scott Wegner
• Created: 25/May/16 18:07
• Updated: 06/Oct/20 21:58
• Resolved: 03/Apr/19 23:52

Description

If a PipelineOptions instance is used as multiple PipelineOptions package-private interfaces from different packages, PipelineOptions.as will throw an exception:

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)

This fails because ProxyInvocationHandler attempts to create a Java Proxy object implementing the full set of interfaces, which has the restriction:

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:

1. PipelineOptions.as is called on the same PipelineOptions instance with multiple package-private interfaces.
2. 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. It's hard to trigger, but possible.

---

I propose we make the behavior for package-private options explicit:

1. Give a better exception message if we hit this issue in PipelineOptions.as listing the non-public interfaces and what packages they're in.
2. Explicitly reject non-public interfaces from PipelineOptionsFactory.register, since this state is global and is easier to cause issues.

Issue Links

• links to: GitHub Pull Request #390
• links to: GitHub Pull Request #862
• links to: GitHub Pull Request #6871
• links to: GitHub Pull Request #8214