[jira] [Commented] (TIKA-3092) Apparent multithreading bug in HWP5 parser

["Tim Allison (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/TIKA-3092?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17083526#comment-17083526 ] 

Tim Allison commented on TIKA-3092:
-----------------------------------

Ok.  This one is spooky...props to anyone who can figure out what's going on.  I have a fix, but no explanation as to why this fix works.

The symptom was that we were getting different text when running multithreaded than when running in a single thread.

In the HwpStreamReader, we use Java's InflaterInputStream with an Inflater to wrap compressed inputstreams -- as a side note, I confirmed there is no diff btwn Java and commons-compress.

We were calling POI IOUtil's ensureSkip which uses a static byte array buffer to read off the right number of bytes.  When I switched that to use an instance byte array buffer for reading/skipping, the problem went away.

This seems to work in both Java 8 and Java 13.  I can't explain the fix, and I can't explain why we haven't seen this problem before.



> Apparent multithreading bug in HWP5 parser
> ------------------------------------------
>
>                 Key: TIKA-3092
>                 URL: https://issues.apache.org/jira/browse/TIKA-3092
>             Project: Tika
>          Issue Type: Task
>            Reporter: Tim Allison
>            Assignee: Tim Allison
>            Priority: Major
>
> We got some weird behavior in the most recent regression tests for 1.24.1 on HWP5 files.  When I ran MultiThreadedTikaTest on .hwp files, I was able to confirm we get different output when running multithreaded.



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