don't use subprocess.call with PIPEs as the child can fill the pipe buf and
deadlock. add a warning to subprocess docs about this, similar to Popen.wait's.
refs http://bugs.jython.org/issue1351
diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
index 4c4f4ae..946a504 100644
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -157,6 +157,12 @@
retcode = call(["ls", "-l"])
+ .. warning::
+
+ Like :meth:`Popen.wait`, this will deadlock if the child process
+ generates enough output to a stdout or stderr pipe such that it blocks
+ waiting for the OS pipe buffer to accept more data.
+
.. function:: check_call(*popenargs, **kwargs)
@@ -171,6 +177,10 @@
.. versionadded:: 2.5
+ .. warning::
+
+ See the warning for :func:`call`.
+
.. function:: check_output(*popenargs, **kwargs)
diff --git a/Lib/test/test_cmd_line.py b/Lib/test/test_cmd_line.py
index efef74f..09945f7 100644
--- a/Lib/test/test_cmd_line.py
+++ b/Lib/test/test_cmd_line.py
@@ -2,6 +2,7 @@
# All tests are executed with environment variables ignored
# See test_cmd_line_script.py for testing of script execution
+import os
import test.test_support, unittest
import sys
import subprocess
@@ -29,8 +30,9 @@
def exit_code(self, *args):
cmd_line = [sys.executable, '-E']
cmd_line.extend(args)
- return subprocess.call(cmd_line, stdout=subprocess.PIPE,
- stderr=subprocess.PIPE)
+ with open(os.devnull, 'w') as devnull:
+ return subprocess.call(cmd_line, stdout=devnull,
+ stderr=subprocess.STDOUT)
def test_directories(self):
self.assertNotEqual(self.exit_code('.'), 0)