Investigate why `commons-io` 2.21.0 breaks SSH agents on upgrade

[timja]

The upgrade in #11276 caused a serious regression in weekly with multiple user reports:

• https://issues.jenkins.io/browse/JENKINS-76295
• [Regression] Could not copy remoting.jar into 'c:\jenkins' on agent - invalid len argument [>2.532,<=2.537] #11312

Darin pope noted in https://groups.google.com/g/jenkinsci-dev/c/bFoynjc1BwY/m/-yViOhaUAgAJ:

deleting the remoting.jar and the remoting directory made them work again

New upgrade has been automatically proposed in #11313

[lemeurherve]

From Jesse at #11310 (comment):

Would be interesting to bisect apache/commons-io@rel/commons-io-2.20.0...rel/commons-io-2.21.0 as the problem may be due to an upstream regression that the devs ought to be alerted to. For example apache/commons-io#779 looks like a possible culprit.

[jglick]

I recently walked @MarkEWaite through a similar example. A little awkward since at each git bisect step you need to mvnd -DskipTests install the lib, and then probably build core with that *-SNAPSHOT version mvnd -am -pl war -Pquick-build install, and somehow run through the test sequence mvn -pl war jetty:run unless you have an automated test for it

[MarkEWaite]

I've bisected the failure to Apache Commons IO pull request:

• Add toByteArray(InputStream input, int size, int bufferSize) apache/commons-io#776

I've shared my observations in a comment on that pull request: apache/commons-io#776 (comment)

A small bash script (named README) is included in the attached repository that shows the issue:

gh-16845.tar.gz

[ppkarwasz]

The root cause is not in Commons IO, but in Trilead SSH and can be fixed by jenkinsci/trilead-ssh2#273.

BTW: did you consider using Apache MINA SSHD instead of maintaining a fork of Trilead?

[stefan6419846]

BTW: did you consider using Apache MINA SSHD instead of maintaining a fork of Trilead?

See https://issues.jenkins.io/browse/JENKINS-64106 and jenkinsci/ssh-agents-plugin#570 for the current state.

[MarkEWaite]

The trilead-ssh2 library with the fix has been released as build-217-jenkins-371.vc1d30dc5a_b_32