Mercurial doesn't work on Mac without python2.7 installed

I'm just got a new Apple Silicon Mac and it does not have python installed as Apple has removed 2.7 however it does have python3 installed.

Apparently the version of Mercurial that comes with sourcetree won't work and in the Mercurial tab is showing the posix_spawn error when trying to show it's version.

While I'm not using Mercurial but instead using Git when I try to clone a git repo it's using the hg command to do and generating the posic_spawn 2 error.

I'm not sure why cloning a git repo from github would be using hg but it's blocking me from being able to do any work with sourctree and I see no way to just tell sourcetree to use the git command instead of hg.

I'm going to try installing Mercurial on the system and switching to it to see if I can get things to work.

The reason it's getting the posix_spawn error when running hg appears to be the shebang line #!/usr/bin/python which their is no python executable but there is a python3 executable.

Changing the shebang to python3 at least fixed it's version showing however trying to clone brought up a tab and spaces error in another python file so it'll need more than that to fix.