[jira] [Commented] (VFS-753) NumberFormatException in SftpFileSystem::getUId

["John Webb (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/VFS-753?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17031078#comment-17031078 ] 

John Webb commented on VFS-753:
-------------------------------

[~ggregory]

I suspect the fix has the side effect of telling the class that execution is enabled on the server when it isn't. detectExecDisabled relies on a throw to return true however the fix simply catches and logs. I obviously don't know the code as well as you but worry that a false negative from detectExecDisabled may lead to undesirable behaviour.

> NumberFormatException in SftpFileSystem::getUId
> -----------------------------------------------
>
>                 Key: VFS-753
>                 URL: https://issues.apache.org/jira/browse/VFS-753
>             Project: Commons VFS
>          Issue Type: Bug
>    Affects Versions: 2.5.0
>            Reporter: John Webb
>            Priority: Major
>             Fix For: 2.6.1
>
>
> When calling FileSystemManager::resolveFile(...) connecting to a specific sftp server a NumberFormat exception is thrown and a FileObject is not returned.
> When the SftpFileSystem constructor is called there is a call to detectExecDisabled which in turn calls getUid. SftpFileSystem::getUId assumes that executeCommand(...) will always return non zero (the channel exit status) for execution failure.
> In the case of the sftp server that we are connecting to, the channel exit status remains zero however the returned buffer contains the string "This server does not provide shell access, only SFTP. Goodbye.". This causes a NumberFormatException in getUId.
> This behaviour does not occur in version 2.4.1
> Here is the relevent snippet from the stack trace:
> java.lang.NumberFormatException: For input string: "This server does not provide shell access, only SFTP. Goodbye."
>        at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
>        at java.lang.Integer.parseInt(Integer.java:580)
>        at java.lang.Integer.parseInt(Integer.java:615)
>        at org.apache.commons.vfs2.provider.sftp.SftpFileSystem.getUId(SftpFileSystem.java:281)
>        at org.apache.commons.vfs2.provider.sftp.SftpFileSystem.detectExecDisabled(SftpFileSystem.java:344)
>        at org.apache.commons.vfs2.provider.sftp.SftpFileSystem.<init>(SftpFileSystem.java:94)
>        at org.apache.commons.vfs2.provider.sftp.SftpFileProvider.doCreateFileSystem(SftpFileProvider.java:93)
>        at org.apache.commons.vfs2.provider.AbstractOriginatingFileProvider.getFileSystem(AbstractOriginatingFileProvider.java:93)
>        at org.apache.commons.vfs2.provider.AbstractOriginatingFileProvider.findFile(AbstractOriginatingFileProvider.java:72)
>        at org.apache.commons.vfs2.provider.AbstractOriginatingFileProvider.findFile(AbstractOriginatingFileProvider.java:56)
>        at org.apache.commons.vfs2.impl.DefaultFileSystemManager.resolveFile(DefaultFileSystemManager.java:717)
>        at org.apache.commons.vfs2.impl.DefaultFileSystemManager.resolveFile(DefaultFileSystemManager.java:654)
>        at com.shortcuts.lambda.google_reserve_sftp.util.SFTPUtil.ls(SFTPUtil.java:68)
>        at com.shortcuts.lambda.google_reserve_sftp.util.SFTPUtilTest.testConnectToGoogle(SFTPUtilTest.java:48)
>        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)



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