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HTTPS or Subversion.
Yes, it's in the README but the suggested fix doesn't work.
(setenv "PATH" (shell-command-to-string "echo $PATH"))
I'm not really sure how I can help you debug it. Let me know what you need.
Evaluate (shell-command-to-string "echo $PATH") in the scratch buffer or via M-x eval-expression, then make sure it is the PATH you expect.
(shell-command-to-string "echo $PATH")
If you have lein under PATH and it works in the terminal, there should be no need to use setenv.
Another way to set up PATH is to Max customize-apropos PATH [ret]. Then find find exec path and Swank path there. However, in my case they do not include ~/bin, which is where lein is located. This has been the case for over 1 year, with 2 Emacs versions, several Leiningen versions and lein-swank plugin updates.
Max customize-apropos PATH [ret]
Evaluating in a scratch buffer gives the wrong $PATH. I fixed it by doing
(setenv "PATH" (shell-command-to-string "source ~/.bashrc; echo $PATH"))
.bashrc is not the right place to customize your $PATH, but if you got it working that's good. Settings that are shell-agnostic go in .profile instead.