Sftp Session cannot open directory from the absolute path

[jonchngau]

In what version(s) of Spring Integration are you seeing this issue? 6.0.0

Describe the bug
After upgrading to 6.0.0,
When using spring integration with sftp inbound, there is exception of SSH_FX_NO_SUCH_FILE thrown when doing file synchronization from remote to local.
After troubleshooting, it is related to SftpSession.doList()
it is now removing all leading and trailing slash.
So, if I used /a/b/c as remote directory in the synchronization.
remotePath = a/b/c
remoteDir = a/b
remoteFile = c

and it will cause the above error, because it regards remoteDir as relative path.
E.g. if home directory is "/home/user", then it will locate /home/user/a/b instead of /a/b

I have tried to extends the DefaultSftpSessionFactory and SftpSession,
it works normally after i change the following code

String remotePath = StringUtils.trimTrailingCharacter(StringUtils.trimLeadingCharacter(path, '/'), '/');

to

String remotePath = StringUtils.trimTrailingCharacter(path, '/');

Please advice the purpose of trim leading slash.

To Reproduce

login to sftp server with remote directory not under home directory

Expected behavior

sftp inbound or outbound to directory outside home directory should be supported.

[artembilan]

login to sftp server with remote directory not under home directory

How to do that please?
How user can navigate into remote dir not under his/her home?
Any code to let us to reproduce?

Thanks

[artembilan]

OK. I think I see what you mean.
The ChannelSftp has the logic like this:

  private String remoteAbsolutePath(String path) throws SftpException{
    if(path.charAt(0)=='/') return path;
    String cwd=getCwd();
//    if(cwd.equals(getHome())) return path;
    if(cwd.endsWith("/")) return cwd+path;
    return cwd+"/"+path;
  }

So, if we have a leading /, it was treated as an absolute path.
Otherwise we navigates it into a user home as relative one.

Need to revise what we have so far with this new SftpClient...

[artembilan]

Proposal: #3976.

This report is another sample to question a report why do we release milestones and release candidates before going GA?
What does stop some of you to follow our requests and test your solution on early stages: https://spring.io/blog/2022/10/25/spring-integration-6-0-0-rc1-available ?