Jenkins + Git plugin CheckoutConflictException
I was getting this error when I installed the new Jenkins 1.505 and using git client plugin 1.0.4. You can downgrade the plugin to 1.0.3 and it might work. I was not really using the git client plugin so removed it in my case
I had the same problem. They have released an update that corrects that error, so you only have to update Jenkins Git Client to 1.0.5. Now it's working.
I just ran into the same issue and wanted to provide an alternative solution:
In the 1.0.4 version info on the plugin's page you can read:
use JGit implementation in GitAPI for all supported methods, until org.jenkinsci.plugins.gitclient.Git.useCLI is set
which seems to be the cause of our problems. But it says that one can work around it by setting org.jenkinsci.plugins.gitclient.Git.useCLI to true.
So just add -Dorg.jenkinsci.plugins.gitclient.Git.useCLI=true to your start script.
On Debian (when using the apt-get version), it's sufficient to update JAVA_ARGS in /etc/default/jenkins (as described here)