Debugging of subprocess.popen has unexpected results and fails

Hi People,

Can any of you please try the following code block and tell me if you get the same problem or if I'm doing something stupid as this is completely stopping me from debugging my scripts and I'm back to old school debug prints everywhere in my code!!

I have logged a bug for this here:
http://youtrack.jetbrains.com/issue/PY-7464

The following code which runs perfectly at the command prompt and PyCharm can also run it without issues however if I try debug it with PyCharm all hell breaks loose and directories are created based on my parameters even if I just run something simple like 'echo HelloWorld'

#!/usr/bin/python3
import os
import subprocess
import sys

# Executes a command given an optional stdin byte string and returns a return code, stdout and stderr from the application
# Example:
# p4filename = "\"" + os.path.join(Variable.getvarvalue("P4PATH"), Variable.getvarvalue("P4FILE")) + "\""
# (retCode, stdout, stderr) = ExecuteCommand(p4filename + " set", None, mystring.encode('utf-8'))
def ExecuteCommand(cmd, cwd = None, stdin_bytes = None):
    if stdin_bytes != None and type(stdin_bytes) != bytes:
        print("ExecuteCommand stdin_bytes must be of type bytes.\n\tIf you have passed a string use your string.encode('UTF-8') to convert the string to a byte array of UFT-8 characters.")
        print("Type passed - %s" % type(stdin_bytes))
        sys.exit(1)
    stdout = ""
    stderr = ""

    if cwd is not None:
        cwd = os.path.realpath(cwd)
        if not os.path.exists(cwd):
            print( "***ERROR*** - Current working directory [%s] does not exist and therefore cannot execute command [%s]" % (cwd, cmd), {"status": "failed"})
            sys.exit(1)
    try:
        process = subprocess.Popen(cmd, stdin=subprocess.PIPE, stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True, cwd=cwd)
        (stdout, stderr) = process.communicate(input=stdin_bytes)
        return (process.returncode, stdout.decode("cp437"), stderr.decode("cp437"))
    except OSError as ex:
        return (ex.errno, "", ex.strerror)

(retcode, stdout, stderr) = ExecuteCommand("echo HelloWorld")
print(retcode)
print(stdout)
print(stderr)

sys.exit(retcode)

Trying to debug the above even without breakpoints gives the following error:

============================================================
C:\Python32\python.exe "C:\Program Files (x86)\JetBrains\PyCharm 2.5.2\helpers\pydev\pydevd.py" –multiproc –client 127.0.0.1 –port 50488 –file D:/Scripts/test/Systray/Build/BuildBinProduct/test.py
pydev debugger: process 6832 is connecting
Connected to pydev debugger (build 117.663)
1

The system cannot find the path specified.
Error occurred while processing: .exe /c ECHO.
A subdirectory or file HELLOWORLD already exists.
Error occurred while processing: HELLOWORLD.


Process finished with exit code 1
============================================================

Any ideas as to what the problem is? I assume my code is not at fault because it works when you run it inside PyCharm or from the command line with expected results.


My system setup is as follows:

PyCharm 2.5.2
Python 3.2.2 (also tested with 3.0.1) from http://www.python.org/
Windows Vista x64