The git importer is missing import subprocess which causes grade clone ... -d <date> to fail.

[maemre]

The git importer (the actions.git module) uses the subprocess module to do piping to get the default branch but it does not import this module, just importing submodule fixes this problem. This path is triggered only when a deadline is given with the -d command line option (so, the importer works fine without a deadline, and it might have gone unnoticed).

[maemre]

Another solution would be to use cmd_exec_capture and process the output using string.split rather than piping it to cut, something along the lines of:

head_branch_line = cmd_exec_capture(['git', 'branch', '--remotes', '--list', '*/HEAD'], wd=local)
# the command above outputs a line like "origin/HEAD -> origin/<main branch>\n", here we extract <main branch>
return head_branch_line.split('/')[2].strip()

@phpeterson-usf if you don't have the bandwidth for this, I can implement this, test it then make a PR.