[jira] Reopened: (COCOON-2070) Releasing of pooled beans might skip recycle() call on aggregated beans (leading to: "Generator already set"-style exceptions)

["Grzegorz Kossakowski (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/COCOON-2070?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Grzegorz Kossakowski reopened COCOON-2070:
------------------------------------------

      Assignee: Grzegorz Kossakowski  (was: Carsten Ziegeler)

In r543066 "slightly" modified patch from Alexander has been committed but this small modification lead to the situation that original problem has *never* been fixed.

Line:
RequestContextHolder.currentRequestAttributes().removeAttribute(this.attributeName, RequestAttributes.SCOPE_REQUEST);

has been *copied* to the enclosing if clause but it should has been *moved*.

See diff available at http://svn.apache.org/viewvc/cocoon/trunk/core/cocoon-sitemap/cocoon-sitemap-impl/src/main/java/org/apache/cocoon/core/container/spring/avalon/PoolableProxyHandler.java?r1=490762&r2=543066&diff_format=h

> Releasing of pooled beans might skip recycle() call on aggregated beans (leading to: "Generator already set"-style exceptions)
> ------------------------------------------------------------------------------------------------------------------------------
>
>                 Key: COCOON-2070
>                 URL: https://issues.apache.org/jira/browse/COCOON-2070
>             Project: Cocoon
>          Issue Type: Bug
>          Components: - Components: Sitemap
>    Affects Versions: 2.2-dev (Current SVN)
>            Reporter: Alexander Klimetschek
>            Assignee: Grzegorz Kossakowski
>            Priority: Blocker
>             Fix For: 2.2-dev (Current SVN)
>
>         Attachments: poolable-recycle-bug.patch
>
>
> There is a serious bug in o.a.c.core.container.spring.avalon.PoolableProxyHandler (and PoolableFactoryBean) that can lead to exceptions like "Cannot set reader. Generator already set". This is because the pipeline impl bean is reused from the pool, but was never recycle()d. The recycle() call is skipped in cases when an exception is thrown by Spring inside PoolableProxyHandler.invoke("putBackIntoAvalonPool") - this exception is simply swalled by both PoolableProxyHandler.run() and PoolableFactoryBean.putIntoPool().
> The typical behaviour is that the first call to the pipeline works, but because the components are put back into the pool unrecycled, the next call will fail. If there is lots of activity, you might get a fresh component from the pool and it might work again, so the error seems quite random.
> The problematic exception happens when RequestContextHolder.currentRequestAttributes() is called when the attributes for the request are null: IllegalStateException("No thread-bound request found:....."). The call to that method happens in the "putBackIntoAvalonPool" case in PoolableProxyHandler.invoke(). The problem is that this code will also be called *after* the request attributes were set to null by the RequestContextListener, because it is registered as a destruction callback, that gets called by Spring after the attribute reset.
> The real chain of calls is as follows:
>   RequestContextListener.requestDestroyed()
>   RequestContextHolder.setRequestAttributes(null)
>   callDestructionCallbacks()
>   PoolableProxyHandler.run()   <- which is a destruction callback
>   PoolableFactoryBean.putIntoPool()
>   PoolableFactoryBean.enteringPool()
>   component.recycle()
>   AvalonServiceManager/Selector.release(childComponent)   <- component releases its childComponent
>   AvalonPoolable.putBackIntoAvalonPool()
>   PoolableProxyHandler.invoke()   <- intercepts the putBackIntoAvalonPool() call
>   RequestContextHolder.currentRequestAttributes()   <-- Exception !!!

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