Core version is not identified properly when that is also a git checkout

#3059316: Tests fail due to undefined index in git_deploy fails due to the same reason. Why would the info version not be set for core? It should either be set from .info data or by git_deploy itself no? This sounds like may be a symptom of a bigger problem?

Just did a little bit of debugging and found out that I can reproduce the error if I have a checked out core, thats probably what drupal test bot also does?

After a bit of digging found that the branch regular expression is not working for core:

          // Any Drupal-formatted branch.
          $branch_preg =  '\d+\.x-\d+\.';

core branch names are 8.7.x and not 8.x-2.x

Patch attached to fix this.

Yay, thanks a lot. I made some minor changes to the code comments and committed.