[jira] [Created] (SSHD-435) internal NPE when trying to sendStatus, sparse feedback as to root cause

["Alex Dommasch (JIRA)" <ji...@apache.org>]

Alex Dommasch created SSHD-435:
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             Summary: internal NPE when trying to sendStatus, sparse feedback as to root cause
                 Key: SSHD-435
                 URL: https://issues.apache.org/jira/browse/SSHD-435
             Project: MINA SSHD
          Issue Type: Bug
    Affects Versions: 0.14.0
            Reporter: Alex Dommasch


When trying to implement a virtual FileSystemView with the SftpSubsystem, there is a corner case that gives very little feedback as to the root cause.  Namely, if, within a directory listing, one of the SshFile entries returns false for doesExist, and null for getAbsolutePath, there is an internal NullPointerException when trying to generate the response.  (When doesExist is false, a FileNotFoundException is thrown by writeAttrs, with getAbsolutePath used as the message.  But sendStatus wrongly assumes e.getMessage() is non-null, triggering a NullPointerException in putString, obscuring the root cause.)

A few possible suggestions:
* guard code to handle this corner case without internal exceptions
* further documentation on implementation requirements for a virtual file system (what needs to be implemented under which circumstances)
* fail fast, with a helpful message, when an implementation fails to uphold a documented contract.




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