Build environment no longer cleaned up with GitLab Runner 11.9.0 on Windows

After upgrading GitLab Runner from 11.8.0 to 11.9.0 using the amd64 build on Windows 10 1809 64-bit, the build environment is no longer cleaned up at the beginning.

After upgrading to 11.9.0 and restarting the service, I get this output: https://gitlab.com/ssrobins/sdl2-example/-/jobs/183013046 Near the top, it shows this error: fatal: remote origin already exists.

And it never deletes any untracked directories like it did before. I get a failure when it tried to initialize my conan package manager repository because it hasn't been cleaned up. I would expect the directory to be clean of any untracked files before starting the build.

If I manually delete GitLab Runner's 'builds' directory I can get one properly working build because I already cleaned it up: https://gitlab.com/ssrobins/sdl2-example/-/jobs/183012639

Here's the build output using GitLab Runner 11.8.0: https://gitlab.com/ssrobins/sdl2-example/-/jobs/183001080 It shows Fetching changes... followed by the deletion of existing untracked directories, as expected.

I have the 11.9.0 runner installed on Mac as well: https://gitlab.com/ssrobins/sdl2-example/-/jobs/183012743 It also shows the new 'fatal: remote origin already exists.' error, but it still properly deleted untracked files.

This is a major regression for me that breaks my build steps so I'm stuck on 11.8.0 until it is fixed.

Workaround

Add git clean -fd using the before_script

job:
  before_script:
    - git clean -fd
  script:
    - my command