https://github.com/python/cpython/commit/df110126971d0271a977ce10779083b3e33... commit: df110126971d0271a977ce10779083b3e335b4da branch: main author: Ross Burton <ross.burton@arm.com> committer: gpshead <greg@krypto.org> date: 2022-08-24T18:37:18-07:00 summary: gh-95243: Mitigate the race condition in testSockName (#96173) find_unused_port() has an inherent race condition, but we can't use bind_port() as that uses .getsockname() which this test is exercising. Try binding to unused ports a few times before failing. Signed-off-by: Ross Burton <ross.burton@arm.com> files: A Misc/NEWS.d/next/Tests/2022-08-22-14-59-42.gh-issue-95243.DeD66V.rst M Lib/test/test_socket.py diff --git a/Lib/test/test_socket.py b/Lib/test/test_socket.py index f1b57fc4071..d808f3f62b9 100644 --- a/Lib/test/test_socket.py +++ b/Lib/test/test_socket.py @@ -1398,10 +1398,21 @@ def testStringToIPv6(self): def testSockName(self): # Testing getsockname() - port = socket_helper.find_unused_port() sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) self.addCleanup(sock.close) - sock.bind(("0.0.0.0", port)) + + # Since find_unused_port() is inherently subject to race conditions, we + # call it a couple times if necessary. + for i in itertools.count(): + port = socket_helper.find_unused_port() + try: + sock.bind(("0.0.0.0", port)) + except OSError as e: + if e.errno != errno.EADDRINUSE or i == 5: + raise + else: + break + name = sock.getsockname() # XXX(nnorwitz): http://tinyurl.com/os5jz seems to indicate # it reasonable to get the host's addr in addition to 0.0.0.0. diff --git a/Misc/NEWS.d/next/Tests/2022-08-22-14-59-42.gh-issue-95243.DeD66V.rst b/Misc/NEWS.d/next/Tests/2022-08-22-14-59-42.gh-issue-95243.DeD66V.rst new file mode 100644 index 00000000000..a9ca1f8b867 --- /dev/null +++ b/Misc/NEWS.d/next/Tests/2022-08-22-14-59-42.gh-issue-95243.DeD66V.rst @@ -0,0 +1,3 @@ +Mitigate the inherent race condition from using find_unused_port() in +testSockName() by trying to find an unused port a few times before failing. +Patch by Ross Burton.