count_recursive can hang in a "git bomb" repo, even with a limit

[jorendorff]

count_recursive with a limit argument will hang if you run it in a "git bomb" repo that contains quadrillions of directories and not enough files to reach the limit.

This means the method can't really be used to enforce limits in code that runs on untrusted repos.

[jorendorff]

It's not super obvious what the right fix is.

• Make count_recursive count both files and directories. That would be a breaking change.
• Make the method return limit if it visits that many directories, even if it hasn't found any files yet. This is odd because the method can return a number greater than the number of files in the repo; the limit isn't just truncation.
• Make the method stop after visiting limit trees, and return whatever it got. But then it may return a number smaller than limit for a repo that is too big to check out, a misleading result.

[josantoniolagunesquiroz-maker]

[josantoniolagunesquiroz-maker]

[josantoniolagunesquiroz-maker]