Question

This code generates ‘AttributeError: ‘Popen’ object has no attribute ‘fileno” when run with Python 2.5.1

Code:

def get_blame(filename):      proc = []     proc.append(Popen(['svn', 'blame', shellquote(filename)], stdout=PIPE))     proc.append(Popen(['tr', '-s', r''\040''], stdin=proc[-1]), stdout=PIPE)     proc.append(Popen(['tr', r''\040'', r'';''], stdin=proc[-1]), stdout=PIPE)     proc.append(Popen(['cut', r'-d', r'\;', '-f', '3'], stdin=proc[-1]), stdout=PIPE)     return proc[-1].stdout.read() 

Stack:

function walk_folder in blame.py at line 55 print_file(os.path.join(os.getcwd(), filename), path)  function print_file in blame.py at line 34 users = get_blame(filename)  function get_blame in blame.py at line 20 proc.append(Popen(['tr', '-s', r''\040''], stdin=proc[-1]), stdout=PIPE)  function __init__ in subprocess.py at line 533 (p2cread, p2cwrite,  function _get_handles in subprocess.py at line 830 p2cread = stdin.fileno() 

This code should be working the python docs describe this usage.

Answer 1

Three things

First, your ()’s are wrong.

Second, the result of subprocess.Popen() is a process object, not a file.

proc = [] proc.append(Popen(['svn', 'blame', shellquote(filename)], stdout=PIPE)) proc.append(Popen(['tr', '-s', r''\040''], stdin=proc[-1]), stdout=PIPE) 

The value of proc[-1] isn’t the file, it’s the process that contains the file.

proc.append(Popen(['tr', '-s', r''\040''], stdin=proc[-1].stdout, stdout=PIPE)) 

Third, don’t do all that tr and cut junk in the shell, few things could be slower. Write the tr and cut processing in Python — it’s faster and simpler.