env: handle shell commands correctly

Previously, environment run method handled shell commands incorrectly
for windows platforms. This change ensures that command list to shell
conversion occurs after shell option is enforced.

poetry/utils/env.py

@@ -908,16 +908,16 @@ class Env(object):
         """
         """
         Run a command inside the Python environment.
         Run a command inside the Python environment.
         """
         """
-        shell = kwargs.get("shell", False)
         call = kwargs.pop("call", False)
         call = kwargs.pop("call", False)
         input_ = kwargs.pop("input_", None)
         input_ = kwargs.pop("input_", None)
 
 
-        if shell:
-            cmd = list_to_shell_command(cmd)
         try:
         try:
             if self._is_windows:
             if self._is_windows:
                 kwargs["shell"] = True
                 kwargs["shell"] = True
 
 
+            if kwargs.get("shell", False):
+                cmd = list_to_shell_command(cmd)
+
             if input_:
             if input_:
                 output = subprocess.run(
                 output = subprocess.run(
                     cmd,
                     cmd,