Bugs item #1531862, was opened at 2006-07-31 18:53 Message generated for change (Comment added) made by loewis You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1531862&group_id=5470
Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Python Library Group: Python 2.5 Status: Closed Resolution: None Priority: 5 Submitted By: John A Meinel (jfmeinel) Assigned to: Gustavo Niemeyer (niemeyer) Summary: subprocess.Popen(cmd, stdout=sys.stdout) fails Initial Comment: I'm currently using subprocess.Popen() to run a command, and I allow the caller to specify where the output should go. One valid output is to send it to sys.stdout (fileno == 1) The subprocess module seems to unconditionally close stdout if a file handle is passed (even if it stdout). Compare: python -c "import subprocess,sys; \ subprocess.Popen(['echo', 'hello'])" versus python -c "import subprocess,sys; \ subprocess.Popen(['echo', 'hello'], stdout=sys.stdout)" or even python -c "import subprocess,sys; \ subprocess.Popen(['echo', 'hello'], stdout=1)" The first one prints 'hello' as expected. The latter two give an error: echo: write error: Bad file descriptor Attached is a possible patch to subprocess.py ---------------------------------------------------------------------- >Comment By: Martin v. Löwis (loewis) Date: 2006-09-10 11:53 Message: Logged In: YES user_id=21627 How did you run the test cases yourself? They should have failed for you as well; buildbot has nothing to do with that. ---------------------------------------------------------------------- Comment By: Gustavo Niemeyer (niemeyer) Date: 2006-09-07 02:50 Message: Logged In: YES user_id=7887 Problem fixed again in 51797 (trunk) and 51794 (2.5), after removing tests which were offending buildbot due to sys.stdout being set to a StringIO. ---------------------------------------------------------------------- Comment By: Gustavo Niemeyer (niemeyer) Date: 2006-09-06 14:52 Message: Logged In: YES user_id=7887 Notice that in all buildbots that reported the failure, subprocess tests still pass correctly. ---------------------------------------------------------------------- Comment By: Gustavo Niemeyer (niemeyer) Date: 2006-09-06 14:48 Message: Logged In: YES user_id=7887 Wow.. this is strange. I don't see any reason why the build bots would break with this change, except for the reason that the test needs to output data to stdout/stderr to check if it's working or not. Is the buildbot checking these somehow? Is there any additional information about these failures? ---------------------------------------------------------------------- Comment By: Neal Norwitz (nnorwitz) Date: 2006-09-06 05:59 Message: Logged In: YES user_id=33168 I have reverted both of these changes since all the buildbots were broken. ---------------------------------------------------------------------- Comment By: Neal Norwitz (nnorwitz) Date: 2006-09-06 04:34 Message: Logged In: YES user_id=33168 This change has broken many (all?) of the buildbots. http://www.python.org/dev/buildbot/all/ ---------------------------------------------------------------------- Comment By: Gustavo Niemeyer (niemeyer) Date: 2006-09-06 04:06 Message: Logged In: YES user_id=7887 Fixed in 51758, backported to 2.5 in 51759. ---------------------------------------------------------------------- Comment By: Gustavo Niemeyer (niemeyer) Date: 2006-09-06 03:44 Message: Logged In: YES user_id=7887 Neal, I'm preparing a patch which fixes this problem as well. Anthony, we should really be checking fd numbers, since they're the ones dup'ed in the child. If sys.stdout has a fileno() not in (0, 1, 2), that's not an issue. ---------------------------------------------------------------------- Comment By: Anthony Baxter (anthonybaxter) Date: 2006-08-16 06:16 Message: Logged In: YES user_id=29957 Making it check for particular FD numbers is a bad idea. Instead, it should check that any FD that's being closed isn't in the set (sys.stdin.fileno(), sys.stdout.fileno(), sys.stderr.fileno()) ---------------------------------------------------------------------- Comment By: Neal Norwitz (nnorwitz) Date: 2006-08-16 06:11 Message: Logged In: YES user_id=33168 If stderr == stdout, this patch won't fix that, will it? Shouldn't you add 1, 2 to the blacklist for stderr? (The patch adds 2, I think 1 may also be required.) ---------------------------------------------------------------------- You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1531862&group_id=5470 _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
