Make executable from outside the virtualenv acessible

poetry/utils/env.py

@@ -302,6 +302,8 @@ class Env(object):
         Return path to the given executable.
         """
         bin_path = (self._bin_dir / bin).with_suffix(".exe" if self._is_windows else "")
+        if not bin_path.exists():
+            return bin
 
         return str(bin_path)