Fix #10554. Added context manager support to Popen objects.
Added a few common Popen uses to the tests like we've done for a few other
instances of adding context managers. Eventually the entire test suite
could be converted to use the context manager format.
diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
index 8f9b9ea..e0bb163 100644
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -208,6 +208,16 @@
underlying CreateProcess() function. They can specify things such as appearance
of the main window and priority for the new process. (Windows only)
+ Popen objects are supported as context managers via the :keyword:`with` statement,
+ closing any open file descriptors on exit.
+ ::
+
+ with Popen(["ifconfig"], stdout=PIPE) as proc:
+ log.write(proc.stdout.read())
+
+ .. versionchanged:: 3.2
+ Added context manager support.
+
.. data:: PIPE
diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 192185d..bdbcc6b 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -697,6 +697,16 @@
data = data.replace(b"\r\n", b"\n").replace(b"\r", b"\n")
return data.decode(encoding)
+ def __enter__(self):
+ return self
+
+ def __exit__(self, type, value, traceback):
+ if self.stdout:
+ self.stdout.close()
+ if self.stderr:
+ self.stderr.close()
+ if self.stdin:
+ self.stdin.close()
def __del__(self, _maxsize=sys.maxsize, _active=_active):
if not self._child_created:
diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py
index d1812e5..ec1e186 100644
--- a/Lib/test/test_subprocess.py
+++ b/Lib/test/test_subprocess.py
@@ -1183,6 +1183,47 @@
# call() function with sequence argument with spaces on Windows
self.with_spaces([sys.executable, self.fname, "ab cd"])
+
+class ContextManagerTests(ProcessTestCase):
+
+ def test_pipe(self):
+ with subprocess.Popen([sys.executable, "-c",
+ "import sys;"
+ "sys.stdout.write('stdout');"
+ "sys.stderr.write('stderr');"],
+ stdout=subprocess.PIPE,
+ stderr=subprocess.PIPE) as proc:
+ self.assertEqual(proc.stdout.read(), b"stdout")
+ self.assertStderrEqual(proc.stderr.read(), b"stderr")
+
+ self.assertTrue(proc.stdout.closed)
+ self.assertTrue(proc.stderr.closed)
+
+ def test_returncode(self):
+ with subprocess.Popen([sys.executable, "-c",
+ "import sys; sys.exit(100)"]) as proc:
+ proc.wait()
+ self.assertEqual(proc.returncode, 100)
+
+ def test_communicate_stdin(self):
+ with subprocess.Popen([sys.executable, "-c",
+ "import sys;"
+ "sys.exit(sys.stdin.read() == 'context')"],
+ stdin=subprocess.PIPE) as proc:
+ proc.communicate(b"context")
+ self.assertEqual(proc.returncode, 1)
+
+ def test_invalid_args(self):
+ with self.assertRaises(EnvironmentError) as c:
+ with subprocess.Popen(['nonexisting_i_hope'],
+ stdout=subprocess.PIPE,
+ stderr=subprocess.PIPE) as proc:
+ pass
+
+ if c.exception.errno != errno.ENOENT: # ignore "no such file"
+ raise c.exception
+
+
def test_main():
unit_tests = (ProcessTestCase,
POSIXProcessTestCase,
@@ -1191,7 +1232,8 @@
CommandTests,
ProcessTestCaseNoPoll,
HelperFunctionTests,
- CommandsWithSpaces)
+ CommandsWithSpaces,
+ ContextManagerTests)
support.run_unittest(*unit_tests)
support.reap_children()
diff --git a/Misc/NEWS b/Misc/NEWS
index e856c6d..434ed23 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -58,6 +58,8 @@
Library
-------
+- Issue #10554: Add context manager support to subprocess.Popen objects.
+
- Issue #8989: email.utils.make_msgid now has a domain parameter that can
override the domain name used in the generated msgid.