Description D T 2021-10-13 08:39:50 EDT

I tried to replace the original jsch with an updated variant, but that caused an NPE.

CloneCommand cloneCommand = Git.cloneRepository()
                .setURI("git@github.com:mwiede/jsch.git")
                .setDirectory(new File("target/junit/clone-test));
assertDoesNotThrow(cloneCommand::call).close(); // <-- Error

This is caused by the following line: https://gerrit.googlesource.com/jgit/+/refs/tags/v5.13.0.202109080827-r/org.eclipse.jgit.ssh.jsch/src/org/eclipse/jgit/transport/JschConfigSessionFactory.java#401

JSch.setConfig("ssh-rsa", JSch.getConfig("signature.rsa"));
JSch.setConfig("ssh-dss", JSch.getConfig("signature.dss"));

These properties are already renamed in that fork, so the old properties are no longer present. IMO jgit should only set the properties if they aren't already set. (As they may already be set to a custom value).

"Original" JSch: https://github.com/is/jsch/blob/master/src/main/java/com/jcraft/jsch/JSch.java
Forked JSch: https://github.com/mwiede/jsch

Related issue in the forked libary:

https://github.com/mwiede/jsch/issues/85

The issue can be worked around using the following code, prior to invoking jgit:

JSch.setConfig("signature.rsa", JSch.getConfig("ssh-rsa"));

My preferred solution would be setting the property, only if it isn't already set:

if (JSch.getConfig("ssh-rsa") == null) {
  JSch.setConfig("ssh-rsa", JSch.getConfig("signature.rsa"));
}
if (JSch.getConfig("ssh-dss") == null) {
  JSch.setConfig("ssh-dss", JSch.getConfig("signature.dss"));
}

As proposed here: https://github.com/mwiede/jsch/issues/85#issuecomment-940985400