[jira] [Updated] (COMPRESS-227) duplicate entries may let ZipFile#getInputStream return null

["Stefan Bodewig (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/COMPRESS-227?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Stefan Bodewig updated COMPRESS-227:
------------------------------------

    Attachment: test.zip

Test archive containing the same (empty) entry twice
                
> duplicate entries may let ZipFile#getInputStream return null
> ------------------------------------------------------------
>
>                 Key: COMPRESS-227
>                 URL: https://issues.apache.org/jira/browse/COMPRESS-227
>             Project: Commons Compress
>          Issue Type: Bug
>          Components: Archivers
>    Affects Versions: 1.5
>            Reporter: Stefan Bodewig
>            Assignee: Stefan Bodewig
>              Labels: zip
>             Fix For: 1.6
>
>         Attachments: test.zip
>
>
> Found while investigating https://issues.apache.org/bugzilla/show_bug.cgi?id=54967
> If an archive contains two entries for the same file readCentralDirectory in ZipFile will only add the first entry to the entries map and only the last to the nameMap map - this is because entries is a LinkedHashMap and nameMap is a "plain" HashMap.
> Normally this wouldn't matter since both ZipArchiveEntry instances are equal and thus it is irrelevant which of the two is used as a key when obtaining the InputStream.
> Things get different, though, if the entry has data inside the local file header as only the first entry is dealt with in resolveLocalFileHeaderData - after this the two instances are no longer equal and nameMap.get(NAME) will return an instance that can no longer be found.
> I intend to modify readCentralDirectory to only add the first entry to nameMap as well and document the behavior.  I'll also start a discussion thread on the dev list on whether we need to provide an additional API with multiple entries per name.

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