If we implement exclusions for clean, we should also include implementing timeout for clean, since it would change the same part of the user interface.

Would be nice if a boolean could be passed in to conditionally control if clean should happen or not.  For fast incremental builds I don't want to clean, but occasionally I need to remove rogue binaries hanging around the workspace and I'd like a to let a build parameter control that

Any news? I would like to see "Clean before checkout" behaviour to have an option to add an exclude pattern:

https://git-scm.com/docs/git-clean

Now I'm executing the command myself without using this behaviour as it does not support it. Example: 'git clean -fdx -e MyFolderToExclude'

I have no plans currently to implement this in the plugin. It is simple to call the git clean command from Jenkins Pipeline and is not much more difficult to call it from Freestyle jobs.

The git clean command does not require authentication, so does not need the added logic that the git plugin provides for authentication support.

I know that. It's what I'm currently doing.

But it would be nice that we could do it in "Clean before checkout" behaviour on Jenkins UI because everywhere where we are calling "checkout scm" uses that configuration. In this case I need to make two lines in my Jenkinsfile. 1-"git clean", 2-"checkout scm". In pipelines that you have stash and unstash you need to copy this code everywhere.

+1 for the script/pipeline maintenance of modifying everywhere that uses 'checkout scm'