I suppose withGitCredentials will be useful either way. I've had a need for that previously, and instead have had to workaround the issue.
We're using job-dsl, so everything is already in git. Although, I'd love to move wipe out repository option to the pipeline, but I have on found the option in the directive generator. Maybe I'm missing something?
I'm aware of the change history, it's not a huge issue for us. This specific job is running a test suite against our live environment. In this scenario multibranch isn't usable for us. We're planning to multibranch pipelines for other things, though the limitation of not being able to specify subdirectory to look at for monorepo setups (like github-branch-pr-change-filter but for branches). There's a Jira raised on that, but doesn't seem to be have been acted on.
Re github provider, non-multibranch pipeline doesn't seem to support anything but git and mercurial. So we're unable to use that.
That's all useful feedback, and appreciate it. Though the slow checkout is still an issue. It's extremely painful. Is there anything I can do to help have this debugged? Running almost the exact same setup locally (though, through docker), the checkout is as fast as I expect it to be.