From b38318dfecef289ed9e38e4e7f996d2f74b7a022 Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sat, 23 Jun 2018 23:21:15 +0000
Subject: [PATCH 01/24] issue #275: build for centos 6 too (python2.6)

---
 tests/build_docker_images.py | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/tests/build_docker_images.py b/tests/build_docker_images.py
index 60ceac10..32e3384b 100755
--- a/tests/build_docker_images.py
+++ b/tests/build_docker_images.py
@@ -12,7 +12,7 @@ import tempfile
 
 
 DEBIAN_DOCKERFILE = r"""
-FROM debian:stable
+FROM debian:stretch
 RUN apt-get update
 RUN \
     apt-get install -y python2.7 openssh-server sudo rsync git strace \
@@ -21,7 +21,18 @@ RUN \
     rm -rf /var/cache/apt
 """
 
-CENTOS_DOCKERFILE = r"""
+CENTOS6_DOCKERFILE = r"""
+FROM centos:6
+RUN yum clean all && \
+    yum -y install -y python2.6 openssh-server sudo rsync git strace sudo \
+                      perl-JSON python-virtualenv && \
+    yum clean all && \
+    groupadd sudo && \
+    ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key
+
+"""
+
+CENTOS7_DOCKERFILE = r"""
 FROM centos:7
 RUN yum clean all && \
     yum -y install -y python2.7 openssh-server sudo rsync git strace sudo \
@@ -49,8 +60,8 @@ RUN \
     useradd -s /bin/bash -m mitogen__readonly_homedir && \
     useradd -s /bin/bash -m mitogen__slow_user && \
     chown -R root: ~mitogen__readonly_homedir && \
-    { for i in `seq 1 21`; do useradd -s /bin/bash -m mitogen__user$i; done; } && \
-    { for i in `seq 1 21`; do echo mitogen__user$i:user$i_password | chpasswd; done; } && \
+    ( for i in `seq 1 21`; do useradd -s /bin/bash -m mitogen__user${i}; done; ) && \
+    ( for i in `seq 1 21`; do echo mitogen__user${i}:user${i}_password | chpasswd; done; ) && \
     ( echo 'root:rootpassword' | chpasswd; ) && \
     ( echo 'mitogen__has_sudo:has_sudo_password' | chpasswd; ) && \
     ( echo 'mitogen__has_sudo_pubkey:has_sudo_pubkey_password' | chpasswd; ) && \
@@ -62,7 +73,7 @@ RUN \
     ( echo 'mitogen__readonly_homedir:readonly_homedir_password' | chpasswd; ) && \
     ( echo 'mitogen__slow_user:slow_user_password' | chpasswd; ) && \
     mkdir ~mitogen__has_sudo_pubkey/.ssh && \
-    { echo '#!/bin/bash\nexec strace -ff -o /tmp/pywrap$$.trace python2.7 "$@"' > /usr/local/bin/pywrap; chmod +x /usr/local/bin/pywrap; }
+    ( echo '#!/bin/bash\nexec strace -ff -o /tmp/pywrap$$.trace python2.7 "$@"' > /usr/local/bin/pywrap; chmod +x /usr/local/bin/pywrap; )
 
 COPY data/docker/mitogen__has_sudo_pubkey.key.pub /home/mitogen__has_sudo_pubkey/.ssh/authorized_keys
 COPY data/docker/mitogen__slow_user.profile /home/mitogen__slow_user/.profile
@@ -89,8 +100,11 @@ def sh(s, *args):
     return shlex.split(s)
 
 
-for (distro, wheel, prefix) in (('debian', 'sudo', DEBIAN_DOCKERFILE),
-                                ('centos', 'wheel', CENTOS_DOCKERFILE)):
+for (distro, wheel, prefix) in (
+        ('debian', 'sudo', DEBIAN_DOCKERFILE),
+        ('centos6', 'wheel', CENTOS6_DOCKERFILE),
+        ('centos7', 'wheel', CENTOS7_DOCKERFILE),
+    ):
     mydir = os.path.abspath(os.path.dirname(__file__))
     with tempfile.NamedTemporaryFile(dir=mydir) as dockerfile_fp:
         dockerfile_fp.write(prefix)

From 38d69a6ecdb38f1747313e3a25c769fdc4943d1a Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 01:55:35 +0100
Subject: [PATCH 02/24] issue #275: tests: drop docker client dep, doesn't run
 on 2.6.

---
 dev_requirements.txt          |  2 -
 tests/show_docker_hostname.py |  5 +--
 tests/testlib.py              | 74 ++++++++++++++++++++++++-----------
 3 files changed, 53 insertions(+), 28 deletions(-)

diff --git a/dev_requirements.txt b/dev_requirements.txt
index c8b6af13..a55be0de 100644
--- a/dev_requirements.txt
+++ b/dev_requirements.txt
@@ -4,8 +4,6 @@ coverage==4.5.1
 Django==1.6.11; python_version < '2.7'
 Django==1.11.5; python_version >= '2.7' # for module_finder_test
 debops==0.7.2
-https://github.com/docker/docker-py/archive/1.10.6.tar.gz; python_version < '2.7'
-docker[tls]==2.5.1; python_version >= '2.7'
 mock==2.0.0
 pytest-catchlog==1.2.2
 pytest==3.1.2
diff --git a/tests/show_docker_hostname.py b/tests/show_docker_hostname.py
index 1dc1cb98..d4326f92 100644
--- a/tests/show_docker_hostname.py
+++ b/tests/show_docker_hostname.py
@@ -5,8 +5,5 @@ For use by the Travis scripts, just print out the hostname of the Docker
 daemon from the environment.
 """
 
-import docker
 import testlib
-
-docker = docker.from_env(version='auto')
-print testlib.get_docker_host(docker)
+print testlib.get_docker_host()
diff --git a/tests/testlib.py b/tests/testlib.py
index 28316ba9..56f2e232 100644
--- a/tests/testlib.py
+++ b/tests/testlib.py
@@ -5,6 +5,7 @@ import os
 import random
 import re
 import socket
+import subprocess
 import sys
 import time
 import urlparse
@@ -15,9 +16,6 @@ import mitogen.core
 import mitogen.master
 import mitogen.utils
 
-if mitogen.is_master:  # TODO: shouldn't be necessary.
-    import docker
-
 
 DATA_DIR = os.path.join(os.path.dirname(__file__), 'data')
 sys.path.append(DATA_DIR)
@@ -34,6 +32,19 @@ def data_path(suffix):
     return path
 
 
+def subprocess__check_output(*popenargs, **kwargs):
+    # Missing from 2.6.
+    process = subprocess.Popen(stdout=subprocess.PIPE, *popenargs, **kwargs)
+    output, _ = process.communicate()
+    retcode = process.poll()
+    if retcode:
+        cmd = kwargs.get("args")
+        if cmd is None:
+            cmd = popenargs[0]
+        raise subprocess.CalledProcessError(retcode, cmd, output=output)
+    return output
+
+
 def wait_for_port(
         host,
         port,
@@ -162,11 +173,12 @@ class TestCase(unittest2.TestCase):
         assert 0, '%r did not raise %r' % (func, exc)
 
 
-def get_docker_host(docker):
-    if docker.api.base_url == 'http+docker://localunixsocket':
+def get_docker_host():
+    url = os.environ.get('DOCKER_HOST')
+    if url in (None, 'http+docker://localunixsocket'):
         return 'localhost'
 
-    parsed = urlparse.urlparse(docker.api.base_url)
+    parsed = urlparse.urlparse(url)
     return parsed.netloc.partition(':')[0]
 
 
@@ -179,29 +191,47 @@ class DockerizedSshDaemon(object):
             self.image = 'mitogen/%s-test' % (distro,)
         return self.image
 
-    def __init__(self):
-        self.docker = docker.from_env(version='auto')
-        self.container_name = 'mitogen-test-%08x' % (random.getrandbits(64),)
-        self.container = self.docker.containers.run(
-            image=self.get_image(),
-            detach=True,
-            privileged=True,
-            publish_all_ports=True,
-        )
-        self.container.reload()
-        self.port = (self.container.attrs['NetworkSettings']['Ports']
-                                         ['22/tcp'][0]['HostPort'])
+    # 22/tcp -> 0.0.0.0:32771
+    PORT_RE = re.compile(r'([^/]+)/([^ ]+) -> ([^:]+):(.*)')
+    port = None
+
+    def _get_container_port(self):
+        s = subprocess__check_output(['docker', 'port', self.container_name])
+        for line in s.splitlines():
+            dport, proto, baddr, bport = self.PORT_RE.match(line).groups()
+            if dport == '22' and proto == 'tcp':
+                self.port = int(bport)
+
         self.host = self.get_host()
+        if self.port is None:
+            raise ValueError('could not find SSH port in: %r' % (s,))
+
+    def start_container(self):
+        self.container_name = 'mitogen-test-%08x' % (random.getrandbits(64),)
+        args = [
+            'docker',
+            'run',
+            '--detach',
+            '--privileged',
+            '--publish-all',
+            '--name', self.container_name,
+            self.get_image()
+        ]
+        subprocess__check_output(args)
+        self._get_container_port()
+
+    def __init__(self):
+        self.start_container()
 
     def get_host(self):
-        return get_docker_host(self.docker)
+        return get_docker_host()
 
     def wait_for_sshd(self):
-        wait_for_port(self.get_host(), int(self.port), pattern='OpenSSH')
+        wait_for_port(self.get_host(), self.port, pattern='OpenSSH')
 
     def close(self):
-        self.container.stop()
-        self.container.remove()
+        args = ['docker', 'rm', '-f', self.container_name]
+        subprocess__check_output(args)
 
 
 class BrokerMixin(object):

From cfd28872929b5c7d548190ec870f80714374bc06 Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 02:46:36 +0100
Subject: [PATCH 03/24] issue #275: default to 'python' for default remote
 interpreter.

So we get 2.4/2.5/2.6/2.7/3.x.
---
 mitogen/parent.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mitogen/parent.py b/mitogen/parent.py
index aeebc43a..88a6ab46 100644
--- a/mitogen/parent.py
+++ b/mitogen/parent.py
@@ -648,7 +648,7 @@ class Stream(mitogen.core.Stream):
     Base for streams capable of starting new slaves.
     """
     #: The path to the remote Python interpreter.
-    python_path = 'python2.7'
+    python_path = 'python'
 
     #: Maximum time to wait for a connection attempt.
     connect_timeout = 30.0

From 4649e11da369cd939f87baa43e9f7628b1838c2e Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 00:33:46 +0100
Subject: [PATCH 04/24] issue #275: Travis build matrix from hell.

dev_requirements.txt:
- drop debops, it's not available for Python2.6
---
 .travis.yml          | 61 ++++++++++++++++++++++++++++++++++----------
 dev_requirements.txt |  1 -
 2 files changed, 47 insertions(+), 15 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index 80c88ee4..e879c748 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,20 +9,53 @@ notifications:
 language: python
 cache: pip
 
-python:
-- "2.7"
-
-env:
-- MODE=mitogen DISTRO=debian
-- MODE=mitogen DISTRO=centos
-- MODE=debops_common VER=2.4.3.0
-- MODE=debops_common VER=2.5.1
-# Ansible tests.
-- MODE=ansible VER=2.4.3.0 DISTRO=debian
-- MODE=ansible VER=2.5.1 DISTRO=centos
-- MODE=ansible VER=2.5.1 DISTRO=debian
-# Sanity check our tests against vanilla Ansible, they should still pass.
-- MODE=ansible VER=2.5.1 DISTRO=debian STRATEGY=linear
+matrix:
+  include:
+    # Mitogen tests.
+    # 2.7 -> 2.7
+    - python: "2.7"
+      env: MODE=mitogen DISTRO=debian
+    # 2.7 -> 2.6
+    - python: "2.7"
+      env: MODE=mitogen DISTRO=centos6
+    # 2.6 -> 2.7
+    - python: "2.6"
+      env: MODE=mitogen DISTRO=centos7
+    # 2.6 -> 2.6
+    - python: "2.6"
+      env: MODE=mitogen DISTRO=centos6
+
+    # Debops tests.
+    # 2.4.3.0; 2.7 -> 2.7
+    - python: "2.7"
+      env: MODE=debops_common VER=2.4.3.0
+    # 2.5.5; 2.7 -> 2.7
+    - python: "2.7"
+      env: MODE=debops_common VER=2.5.5
+
+    # ansible_mitogen tests.
+    # 2.4.3.0; Debian; 2.7 -> 2.7
+    - python: "2.7"
+      env: MODE=ansible VER=2.4.3.0 DISTRO=debian
+    # 2.5.5; Debian; 2.7 -> 2.7
+    - python: "2.7"
+      env: MODE=ansible VER=2.5.5 DISTRO=debian
+    # 2.5.5; CentOS; 2.7 -> 2.7
+    - python: "2.7"
+      env: MODE=ansible VER=2.5.5 DISTRO=centos7
+    # 2.5.5; CentOS; 2.7 -> 2.6
+    - python: "2.7"
+      env: MODE=ansible VER=2.5.5 DISTRO=centos6
+    # 2.5.5; CentOS; 2.6 -> 2.7
+    - python: "2.6"
+      env: MODE=ansible VER=2.5.5 DISTRO=centos7
+    # 2.5.5; CentOS; 2.6 -> 2.6
+    - python: "2.6"
+      env: MODE=ansible VER=2.5.5 DISTRO=centos6
+
+    # Sanity check our tests against vanilla Ansible, they should pass.
+    - python: "2.7"
+      env: MODE=ansible VER=2.5.5 DISTRO=debian STRATEGY=linear
 
 install:
 - pip install -r dev_requirements.txt
diff --git a/dev_requirements.txt b/dev_requirements.txt
index a55be0de..202f2b9f 100644
--- a/dev_requirements.txt
+++ b/dev_requirements.txt
@@ -3,7 +3,6 @@ ansible==2.5.2
 coverage==4.5.1
 Django==1.6.11; python_version < '2.7'
 Django==1.11.5; python_version >= '2.7' # for module_finder_test
-debops==0.7.2
 mock==2.0.0
 pytest-catchlog==1.2.2
 pytest==3.1.2

From 1d04a99adba7730e496d855964c2cfc33e929c46 Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 04:34:59 +0100
Subject: [PATCH 05/24] issue #275: missing check_output() call

---
 tests/responder_test.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/responder_test.py b/tests/responder_test.py
index 3f6f66a9..86e6dd7e 100644
--- a/tests/responder_test.py
+++ b/tests/responder_test.py
@@ -30,7 +30,7 @@ class GoodModulesTest(testlib.RouterMixin, unittest2.TestCase):
         # Ensure a program composed of a single script can be imported
         # successfully.
         args = [sys.executable, testlib.data_path('self_contained_program.py')]
-        output = subprocess.check_output(args)
+        output = testlib.subprocess__check_output(args)
         self.assertEquals(output, "['__main__', 50]\n")
 
 

From e0c116a29fab83a8c8742057fe34d6f8ed8e549c Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 04:47:18 +0100
Subject: [PATCH 06/24] issue #275: logging package uses classic classes in
 2.6.

---
 mitogen/core.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mitogen/core.py b/mitogen/core.py
index 9c9a14af..1a854d11 100644
--- a/mitogen/core.py
+++ b/mitogen/core.py
@@ -278,7 +278,7 @@ class PidfulStreamHandler(logging.StreamHandler):
     def emit(self, record):
         if self.open_pid != os.getpid():
             self._reopen()
-        return super(PidfulStreamHandler, self).emit(record)
+        logging.StreamHandler.emit(self, record)
 
 
 def enable_debug_logging():

From 6d618593f301187c04ee0f93bcac30bcaba766f9 Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 16:27:34 +0100
Subject: [PATCH 07/24] issue #275: Python 2.6 reports linux as 'linux3'.

---
 tests/fork_test.py | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tests/fork_test.py b/tests/fork_test.py
index 61c0e16d..47160855 100644
--- a/tests/fork_test.py
+++ b/tests/fork_test.py
@@ -19,6 +19,8 @@ PLATFORM_TO_PATH = {
     ('darwin', True): '/usr/lib/libssl.dylib',
     ('linux2', False): '/usr/lib/libssl.so',
     ('linux2', True): '/usr/lib/x86_64-linux-gnu/libssl.so',
+    ('linux3', False): '/usr/lib/libssl.so',
+    ('linux3', True): '/usr/lib/x86_64-linux-gnu/libssl.so',
 }
 
 c_ssl = ctypes.CDLL(PLATFORM_TO_PATH[sys.platform, IS_64BIT])

From 3b1cc3676cf68038abc60b5d3875c6d4bd2974db Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 17:01:15 +0100
Subject: [PATCH 08/24] issue #275: ssh_debug_level=3 for tests

---
 tests/testlib.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tests/testlib.py b/tests/testlib.py
index 56f2e232..ae2d5504 100644
--- a/tests/testlib.py
+++ b/tests/testlib.py
@@ -274,6 +274,7 @@ class DockerMixin(RouterMixin):
         kwargs.setdefault('hostname', self.dockerized_ssh.host)
         kwargs.setdefault('port', self.dockerized_ssh.port)
         kwargs.setdefault('check_host_keys', 'ignore')
+        kwargs.setdefault('ssh_debug_level', '3')
         return self.router.ssh(**kwargs)
 
     def docker_ssh_any(self, **kwargs):

From 60ad75f4362e6679beca586738015f7e8f8100eb Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 17:11:52 +0100
Subject: [PATCH 09/24] issue #275: Tidier SSH debug logging.

---
 mitogen/ssh.py | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/mitogen/ssh.py b/mitogen/ssh.py
index 5c0df8dc..9ba5a914 100644
--- a/mitogen/ssh.py
+++ b/mitogen/ssh.py
@@ -58,8 +58,10 @@ def _filter_debug(stream, it, buf):
         if not buf.startswith(DEBUG_PREFIXES):
             return buf
         while '\n' in buf:
+            if not buf.startswith(DEBUG_PREFIXES):
+                return buf
             line, _, buf = buf.partition('\n')
-            LOG.debug('%r: received %r', stream, line.rstrip())
+            LOG.debug('%r: %s', stream, line.rstrip())
         try:
             buf += next(it)
         except StopIteration:
@@ -77,7 +79,8 @@ def filter_debug(stream, it):
     for chunk in it:
         chunk = _filter_debug(stream, it, chunk)
         if chunk:
-            yield chunk
+            for line in chunk.splitlines():
+                yield line
 
 
 class PasswordError(mitogen.core.StreamError):
@@ -219,7 +222,7 @@ class Stream(mitogen.parent.Stream):
 
         for buf in filter_debug(self, it):
             LOG.debug('%r: received %r', self, buf)
-            if buf.endswith('EC0\n'):
+            if buf.endswith('EC0'):
                 self._router.broker.start_receive(self.tty_stream)
                 self._ec0_received()
                 return

From e5d02b948b01f1a9b510a6f8cfeecc88ae2bb01b Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 17:19:42 +0100
Subject: [PATCH 10/24] issue #275: travis: run_tests with -vvv

---
 .travis/mitogen_tests.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.travis/mitogen_tests.sh b/.travis/mitogen_tests.sh
index 01e24963..db393d73 100755
--- a/.travis/mitogen_tests.sh
+++ b/.travis/mitogen_tests.sh
@@ -2,4 +2,4 @@
 # Run the Mitogen tests.
 
 MITOGEN_TEST_DISTRO="${DISTRO:-debian}"
-MITOGEN_LOG_LEVEL=debug PYTHONPATH=. ${TRAVIS_BUILD_DIR}/run_tests
+MITOGEN_LOG_LEVEL=debug PYTHONPATH=. ${TRAVIS_BUILD_DIR}/run_tests -vvv

From 83617ad1928589ca1e1f596ca18f5755597db044 Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 17:23:10 +0100
Subject: [PATCH 11/24] issue #275: tests: cache virtualenvs too

---
 .travis.yml | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/.travis.yml b/.travis.yml
index e879c748..94a9aff5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,10 @@ notifications:
   email: false
 
 language: python
-cache: pip
+cache:
+- pip
+- directories:
+  - /home/travis/virtualenv
 
 matrix:
   include:

From fbd5837cf2427469b554eeb1bdda15fd0829b5dd Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 17:31:50 +0100
Subject: [PATCH 12/24] issue #275: parent: use TIOCSCTTY on Linux too.

This appears to be harmless, except for Python 2.6 on Linux/Travis,
where for some reason (some stdlib change?) simply opening the TTY is
insufficient.
---
 mitogen/parent.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mitogen/parent.py b/mitogen/parent.py
index 88a6ab46..4e2b1c60 100644
--- a/mitogen/parent.py
+++ b/mitogen/parent.py
@@ -189,8 +189,9 @@ def _acquire_controlling_tty():
         # On Linux, the controlling tty becomes the first tty opened by a
         # process lacking any prior tty.
         os.close(os.open(os.ttyname(2), os.O_RDWR))
-    if sys.platform.startswith('freebsd') or sys.platform == 'darwin':
-        # On BSD an explicit ioctl is required.
+    if hasattr(termios, 'TIOCSCTTY'):
+        # On BSD an explicit ioctl is required. For some inexplicable reason,
+        # Python 2.6 on Travis also requires it.
         fcntl.ioctl(2, termios.TIOCSCTTY)
 
 

From 84fa3ff024df4ed93ff2e1e7d099b3427dee569a Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 17:45:05 +0000
Subject: [PATCH 13/24] issue #275: ssh: state machine-ish filter_debug()

---
 mitogen/ssh.py | 47 +++++++++++++++++++++++++++--------------------
 1 file changed, 27 insertions(+), 20 deletions(-)

diff --git a/mitogen/ssh.py b/mitogen/ssh.py
index 9ba5a914..c710f990 100644
--- a/mitogen/ssh.py
+++ b/mitogen/ssh.py
@@ -53,21 +53,6 @@ HOSTKEY_FAIL = 'host key verification failed.'
 DEBUG_PREFIXES = ('debug1:', 'debug2:', 'debug3:')
 
 
-def _filter_debug(stream, it, buf):
-    while True:
-        if not buf.startswith(DEBUG_PREFIXES):
-            return buf
-        while '\n' in buf:
-            if not buf.startswith(DEBUG_PREFIXES):
-                return buf
-            line, _, buf = buf.partition('\n')
-            LOG.debug('%r: %s', stream, line.rstrip())
-        try:
-            buf += next(it)
-        except StopIteration:
-            return buf
-
-
 def filter_debug(stream, it):
     """
     Read line chunks from it, either yielding them directly, or building up and
@@ -76,11 +61,33 @@ def filter_debug(stream, it):
     This contains the mess of dealing with both line-oriented input, and partial
     lines such as the password prompt.
     """
+    state = 'start_of_line'
+    buf = ''
     for chunk in it:
-        chunk = _filter_debug(stream, it, chunk)
-        if chunk:
-            for line in chunk.splitlines():
-                yield line
+        buf += chunk
+        while buf:
+            if state == 'start_of_line':
+                if len(buf) < 8:
+                    # short read near the buffer limit, block waiting for at
+                    # least 8 bytes so we can discern either a debug line, or
+                    # the minimum desired interesting token from above
+                    # ('password').
+                    break
+                elif buf.startswith(DEBUG_PREFIXES):
+                    state = 'in_debug'
+                else:
+                    state = 'in_plain'
+            elif state == 'in_debug':
+                if '\n' not in buf:
+                    break
+                line, _, buf = buf.partition('\n')
+                LOG.debug('%r: %s', stream, line.rstrip())
+                state = 'start_of_line'
+            elif state == 'in_plain':
+                line, nl, buf = buf.partition('\n')
+                yield line + nl
+                if nl:
+                    state = 'start_of_line'
 
 
 class PasswordError(mitogen.core.StreamError):
@@ -222,7 +229,7 @@ class Stream(mitogen.parent.Stream):
 
         for buf in filter_debug(self, it):
             LOG.debug('%r: received %r', self, buf)
-            if buf.endswith('EC0'):
+            if buf.endswith('EC0\n'):
                 self._router.broker.start_receive(self.tty_stream)
                 self._ec0_received()
                 return

From d6126a95169e2984208ee092daae93607c20fea9 Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 18:28:50 +0000
Subject: [PATCH 14/24] issue #275: parent/ssh: centralize EC0_MARKER and
 change it for ssh.py.

Must maintain a minimum buffer length prior to deciding whether we have
an interesting token, and 'EC0' is too short for that.
---
 docs/howitworks.rst | 19 ++++++++++++-------
 mitogen/parent.py   | 12 ++++++++----
 mitogen/ssh.py      | 10 +++++-----
 mitogen/su.py       |  2 +-
 mitogen/sudo.py     |  2 +-
 5 files changed, 27 insertions(+), 18 deletions(-)

diff --git a/docs/howitworks.rst b/docs/howitworks.rst
index 0b0ae42d..b14ceab7 100644
--- a/docs/howitworks.rst
+++ b/docs/howitworks.rst
@@ -51,7 +51,7 @@ can be recovered by the bootstrapped process later. It then forks into a new
 process.
 
 After fork, the parent half overwrites its ``stdin`` with the read end of the
-pipe, and the child half writes the string ``EC0\n``, then begins reading the
+pipe, and the child half writes the string ``MITOGEN0\n``, then begins reading the
 :py:mod:`zlib`-compressed payload supplied on ``stdin`` by the master, and
 writing the decompressed result to the write-end of the UNIX pipe.
 
@@ -112,12 +112,17 @@ fetched from the master a second time.
 Signalling Success
 ##################
 
-Once the first stage has signalled ``EC0\n``, the master knows it is ready to
-receive the compressed bootstrap. After decompressing and writing the bootstrap
-source to its parent Python interpreter, the first stage writes the string
-``EC1\n`` to ``stdout`` before exiting. The master process waits for this
-string before considering bootstrap successful and the child's ``stdio`` ready
-to receive messages.
+Once the first stage has signalled ``MITO000\n``, the master knows it is ready
+to receive the compressed bootstrap. After decompressing and writing the
+bootstrap source to its parent Python interpreter, the first stage writes the
+string ``MITO001\n`` to ``stdout`` before exiting. The master process waits for
+this string before considering bootstrap successful and the child's ``stdio``
+ready to receive messages.
+
+The signal value is 8 bytes to match the minimum chunk size required to
+disambiguate between lines containing an interesting token during SSH password
+authentication, a debug message from the SSH client itself, or a message from
+the first stage.
 
 
 ExternalContext.main()
diff --git a/mitogen/parent.py b/mitogen/parent.py
index 4e2b1c60..c999c89a 100644
--- a/mitogen/parent.py
+++ b/mitogen/parent.py
@@ -790,11 +790,11 @@ class Stream(mitogen.core.Stream):
                 sys.executable += sys.version[:3]
             os.environ['ARGV0']=sys.executable
             os.execl(sys.executable,sys.executable+'(mitogen:CONTEXT_NAME)')
-        os.write(1,'EC0\n')
+        os.write(1,'MITO000\n')
         C=_(os.fdopen(0,'rb').read(PREAMBLE_COMPRESSED_LEN),'zip')
         os.fdopen(W,'w',0).write(C)
         os.fdopen(w,'w',0).write('PREAMBLE_LEN\n'+C)
-        os.write(1,'EC1\n')
+        os.write(1,'MITO001\n')
 
     def get_boot_command(self):
         source = inspect.getsource(self._first_stage)
@@ -870,13 +870,17 @@ class Stream(mitogen.core.Stream):
             self._reap_child()
             raise
 
+    #: For ssh.py, this must be at least max(len('password'), len('debug1:'))
+    EC0_MARKER = 'MITO000\n'
+    EC1_MARKER = 'MITO001\n'
+
     def _ec0_received(self):
         LOG.debug('%r._ec0_received()', self)
         write_all(self.transmit_side.fd, self.get_preamble())
-        discard_until(self.receive_side.fd, 'EC1\n', self.connect_deadline)
+        discard_until(self.receive_side.fd, 'MITO001\n', self.connect_deadline)
 
     def _connect_bootstrap(self, extra_fd):
-        discard_until(self.receive_side.fd, 'EC0\n', self.connect_deadline)
+        discard_until(self.receive_side.fd, 'MITO000\n', self.connect_deadline)
         self._ec0_received()
 
 
diff --git a/mitogen/ssh.py b/mitogen/ssh.py
index c710f990..161b5323 100644
--- a/mitogen/ssh.py
+++ b/mitogen/ssh.py
@@ -68,10 +68,10 @@ def filter_debug(stream, it):
         while buf:
             if state == 'start_of_line':
                 if len(buf) < 8:
-                    # short read near the buffer limit, block waiting for at
-                    # least 8 bytes so we can discern either a debug line, or
-                    # the minimum desired interesting token from above
-                    # ('password').
+                    # short read near buffer limit, block awaiting at least 8
+                    # bytes so we can discern a debug line, or the minimum
+                    # interesting token from above or the bootstrap
+                    # ('password', 'MITO000\n').
                     break
                 elif buf.startswith(DEBUG_PREFIXES):
                     state = 'in_debug'
@@ -229,7 +229,7 @@ class Stream(mitogen.parent.Stream):
 
         for buf in filter_debug(self, it):
             LOG.debug('%r: received %r', self, buf)
-            if buf.endswith('EC0\n'):
+            if buf.endswith(self.EC0_MARKER):
                 self._router.broker.start_receive(self.tty_stream)
                 self._ec0_received()
                 return
diff --git a/mitogen/su.py b/mitogen/su.py
index 2cc3406b..ce81eed5 100644
--- a/mitogen/su.py
+++ b/mitogen/su.py
@@ -97,7 +97,7 @@ class Stream(mitogen.parent.Stream):
 
         for buf in it:
             LOG.debug('%r: received %r', self, buf)
-            if buf.endswith('EC0\n'):
+            if buf.endswith(self.EC0_MARKER):
                 self._ec0_received()
                 return
             if any(s in buf.lower() for s in self.incorrect_prompts):
diff --git a/mitogen/sudo.py b/mitogen/sudo.py
index 5d2911fc..32287f9f 100644
--- a/mitogen/sudo.py
+++ b/mitogen/sudo.py
@@ -168,7 +168,7 @@ class Stream(mitogen.parent.Stream):
 
         for buf in it:
             LOG.debug('%r: received %r', self, buf)
-            if buf.endswith('EC0\n'):
+            if buf.endswith(self.EC0_MARKER):
                 self._ec0_received()
                 return
             elif PASSWORD_PROMPT in buf.lower():

From 6e0883f3692392123680274f69d27b202939a9ad Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 18:30:16 +0000
Subject: [PATCH 15/24] issue #275: tests: fix bug in 2.6 compat
 check_output(), ignore it for >2.6.

---
 tests/testlib.py | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tests/testlib.py b/tests/testlib.py
index ae2d5504..46868f6d 100644
--- a/tests/testlib.py
+++ b/tests/testlib.py
@@ -41,9 +41,12 @@ def subprocess__check_output(*popenargs, **kwargs):
         cmd = kwargs.get("args")
         if cmd is None:
             cmd = popenargs[0]
-        raise subprocess.CalledProcessError(retcode, cmd, output=output)
+        raise subprocess.CalledProcessError(retcode, cmd)
     return output
 
+if hasattr(subprocess, 'check_output'):
+    subprocess__check_output = subprocess.check_output
+
 
 def wait_for_port(
         host,

From 7b84a2c2e4c6c3cd8962131fc80cbcca1e544b96 Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 18:47:29 +0000
Subject: [PATCH 16/24] issue #275: tests: use same EC0_MARKER as parent.py

---
 tests/first_stage_test.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tests/first_stage_test.py b/tests/first_stage_test.py
index d868f8b5..1698a435 100644
--- a/tests/first_stage_test.py
+++ b/tests/first_stage_test.py
@@ -35,7 +35,7 @@ class CommandLineTest(testlib.RouterMixin, testlib.TestCase):
         )
         stdout, stderr = proc.communicate()
         self.assertEquals(0, proc.returncode)
-        self.assertEquals("EC0\n", stdout)
+        self.assertEquals(mitogen.parent.Stream.EC0_MARKER, stdout)
         self.assertIn("Error -5 while decompressing data: incomplete or truncated stream", stderr)
 
 

From 4be8afa3d3cb31a934211c822e5a972477c2b29b Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 20:10:32 +0100
Subject: [PATCH 17/24] issue #275: tests: fix test_simple for 2.6.

---
 tests/module_finder_test.py | 26 ++++++++++++++++----------
 1 file changed, 16 insertions(+), 10 deletions(-)

diff --git a/tests/module_finder_test.py b/tests/module_finder_test.py
index 1c77bdee..c2e64cfb 100644
--- a/tests/module_finder_test.py
+++ b/tests/module_finder_test.py
@@ -1,4 +1,5 @@
 import inspect
+import sys
 
 import unittest2
 
@@ -190,19 +191,24 @@ class FindRelatedTest(testlib.TestCase):
     def call(self, fullname):
         return self.klass().find_related(fullname)
 
+    SIMPLE_EXPECT = set([
+        'mitogen',
+        'mitogen.compat',
+        'mitogen.compat.collections',
+        'mitogen.compat.functools',
+        'mitogen.core',
+        'mitogen.master',
+        'mitogen.minify',
+        'mitogen.parent',
+    ])
+
+    if sys.version_info < (2, 7):
+        SIMPLE_EXPECT.add('mitogen.compat.tokenize')
+
     def test_simple(self):
         import mitogen.fakessh
         related = self.call('mitogen.fakessh')
-        self.assertEquals(related, [
-            'mitogen',
-            'mitogen.compat',
-            'mitogen.compat.collections',
-            'mitogen.compat.functools',
-            'mitogen.core',
-            'mitogen.master',
-            'mitogen.minify',
-            'mitogen.parent',
-        ])
+        self.assertEquals(set(related), self.SIMPLE_EXPECT)
 
     def test_django_pkg(self):
         import django

From cec564654ec5aebc250d4f2b3c32a7f2c9ff898c Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 21:12:26 +0100
Subject: [PATCH 18/24] issue #275: tests: fix module_finder_test for 2.6.

---
 dev_requirements.txt        |   4 +-
 tests/module_finder_test.py | 133 ++++++++++--------------------------
 2 files changed, 38 insertions(+), 99 deletions(-)

diff --git a/dev_requirements.txt b/dev_requirements.txt
index 202f2b9f..36e458f3 100644
--- a/dev_requirements.txt
+++ b/dev_requirements.txt
@@ -1,9 +1,9 @@
 -r docs/docs-requirements.txt
 ansible==2.5.2
 coverage==4.5.1
-Django==1.6.11; python_version < '2.7'
-Django==1.11.5; python_version >= '2.7' # for module_finder_test
+Django==1.6.11  # Last version supporting 2.6.
 mock==2.0.0
+pytz==2012d  # Last 2.6-compat version.
 pytest-catchlog==1.2.2
 pytest==3.1.2
 PyYAML==3.11; python_version < '2.7'
diff --git a/tests/module_finder_test.py b/tests/module_finder_test.py
index c2e64cfb..d4db641f 100644
--- a/tests/module_finder_test.py
+++ b/tests/module_finder_test.py
@@ -1,4 +1,5 @@
 import inspect
+import os
 import sys
 
 import unittest2
@@ -143,13 +144,6 @@ class FindRelatedImportsTest(testlib.TestCase):
             'mitogen.parent',
         ])
 
-    def test_django_pkg(self):
-        import django
-        related = self.call('django')
-        self.assertEquals(related, [
-            'django.utils.version',
-        ])
-
     def test_django_db(self):
         import django.db
         related = self.call('django.db')
@@ -158,6 +152,7 @@ class FindRelatedImportsTest(testlib.TestCase):
             'django.core',
             'django.core.signals',
             'django.db.utils',
+            'django.utils.functional',
         ])
 
     def test_django_db_models(self):
@@ -175,10 +170,9 @@ class FindRelatedImportsTest(testlib.TestCase):
             'django.db.models.expressions',
             'django.db.models.fields',
             'django.db.models.fields.files',
-            'django.db.models.fields.proxy',
             'django.db.models.fields.related',
-            'django.db.models.indexes',
-            'django.db.models.lookups',
+            'django.db.models.fields.subclassing',
+            'django.db.models.loading',
             'django.db.models.manager',
             'django.db.models.query',
             'django.db.models.signals',
@@ -210,14 +204,27 @@ class FindRelatedTest(testlib.TestCase):
         related = self.call('mitogen.fakessh')
         self.assertEquals(set(related), self.SIMPLE_EXPECT)
 
-    def test_django_pkg(self):
-        import django
-        related = self.call('django')
-        self.assertEquals(related, [
-            'django.utils',
-            'django.utils.lru_cache',
-            'django.utils.version',
-        ])
+
+class DjangoFindRelatedTest(testlib.TestCase):
+    klass = mitogen.master.ModuleFinder
+    maxDiff = None
+
+    def call(self, fullname):
+        return self.klass().find_related(fullname)
+
+    WEBPROJECT_PATH = testlib.data_path('webproject')
+
+    @classmethod
+    def setUpClass(cls):
+        super(DjangoFindRelatedTest, cls).setUpClass()
+        sys.path.append(cls.WEBPROJECT_PATH)
+        os.environ['DJANGO_SETTINGS_MODULE'] = 'webproject.settings'
+
+    @classmethod
+    def tearDownClass(cls):
+        sys.path.remove(cls.WEBPROJECT_PATH)
+        del os.environ['DJANGO_SETTINGS_MODULE']
+        super(DjangoFindRelatedTest, cls).tearDownClass()
 
     def test_django_db(self):
         import django.db
@@ -232,17 +239,14 @@ class FindRelatedTest(testlib.TestCase):
             'django.db.utils',
             'django.dispatch',
             'django.dispatch.dispatcher',
-            'django.dispatch.weakref_backports',
+            'django.dispatch.saferef',
             'django.utils',
             'django.utils._os',
-            'django.utils.deprecation',
             'django.utils.encoding',
             'django.utils.functional',
-            'django.utils.inspect',
-            'django.utils.lru_cache',
+            'django.utils.importlib',
             'django.utils.module_loading',
             'django.utils.six',
-            'django.utils.version',
         ])
 
     def test_django_db_models(self):
@@ -250,31 +254,9 @@ class FindRelatedTest(testlib.TestCase):
         related = self.call('django.db.models')
         self.assertEquals(related, [
             'django',
-            'django.apps',
-            'django.apps.config',
-            'django.apps.registry',
             'django.conf',
             'django.conf.global_settings',
             'django.core',
-            'django.core.cache',
-            'django.core.cache.backends',
-            'django.core.cache.backends.base',
-            'django.core.checks',
-            'django.core.checks.caches',
-            'django.core.checks.compatibility',
-            'django.core.checks.compatibility.django_1_10',
-            'django.core.checks.compatibility.django_1_8_0',
-            'django.core.checks.database',
-            'django.core.checks.messages',
-            'django.core.checks.model_checks',
-            'django.core.checks.registry',
-            'django.core.checks.security',
-            'django.core.checks.security.base',
-            'django.core.checks.security.csrf',
-            'django.core.checks.security.sessions',
-            'django.core.checks.templates',
-            'django.core.checks.urls',
-            'django.core.checks.utils',
             'django.core.exceptions',
             'django.core.files',
             'django.core.files.base',
@@ -287,7 +269,8 @@ class FindRelatedTest(testlib.TestCase):
             'django.core.validators',
             'django.db',
             'django.db.backends',
-            'django.db.backends.utils',
+            'django.db.backends.signals',
+            'django.db.backends.util',
             'django.db.models.aggregates',
             'django.db.models.base',
             'django.db.models.constants',
@@ -297,88 +280,44 @@ class FindRelatedTest(testlib.TestCase):
             'django.db.models.fields.files',
             'django.db.models.fields.proxy',
             'django.db.models.fields.related',
-            'django.db.models.fields.related_descriptors',
-            'django.db.models.fields.related_lookups',
-            'django.db.models.fields.reverse_related',
-            'django.db.models.functions',
-            'django.db.models.functions.base',
-            'django.db.models.functions.datetime',
-            'django.db.models.indexes',
-            'django.db.models.lookups',
+            'django.db.models.fields.subclassing',
+            'django.db.models.loading',
             'django.db.models.manager',
             'django.db.models.options',
             'django.db.models.query',
             'django.db.models.query_utils',
+            'django.db.models.related',
             'django.db.models.signals',
             'django.db.models.sql',
-            'django.db.models.sql.constants',
-            'django.db.models.sql.datastructures',
-            'django.db.models.sql.query',
-            'django.db.models.sql.subqueries',
-            'django.db.models.sql.where',
-            'django.db.models.utils',
             'django.db.transaction',
             'django.db.utils',
             'django.dispatch',
             'django.dispatch.dispatcher',
-            'django.dispatch.weakref_backports',
+            'django.dispatch.saferef',
             'django.forms',
-            'django.forms.boundfield',
-            'django.forms.fields',
-            'django.forms.forms',
-            'django.forms.formsets',
-            'django.forms.models',
-            'django.forms.renderers',
-            'django.forms.utils',
-            'django.forms.widgets',
-            'django.template',
-            'django.template.backends',
-            'django.template.backends.base',
-            'django.template.backends.django',
-            'django.template.backends.jinja2',
-            'django.template.base',
-            'django.template.context',
-            'django.template.engine',
-            'django.template.exceptions',
-            'django.template.library',
-            'django.template.loader',
-            'django.template.utils',
-            'django.templatetags',
-            'django.templatetags.static',
             'django.utils',
             'django.utils._os',
             'django.utils.crypto',
             'django.utils.datastructures',
-            'django.utils.dateformat',
             'django.utils.dateparse',
-            'django.utils.dates',
-            'django.utils.datetime_safe',
-            'django.utils.deconstruct',
             'django.utils.decorators',
             'django.utils.deprecation',
-            'django.utils.duration',
             'django.utils.encoding',
-            'django.utils.formats',
             'django.utils.functional',
-            'django.utils.html',
-            'django.utils.html_parser',
-            'django.utils.http',
-            'django.utils.inspect',
+            'django.utils.importlib',
             'django.utils.ipv6',
             'django.utils.itercompat',
-            'django.utils.lru_cache',
             'django.utils.module_loading',
-            'django.utils.numberformat',
             'django.utils.safestring',
             'django.utils.six',
             'django.utils.text',
             'django.utils.timezone',
             'django.utils.translation',
             'django.utils.tree',
-            'django.utils.version',
+            'django.utils.tzinfo',
+            'pkg_resources',
             'pytz',
             'pytz.exceptions',
-            'pytz.lazy',
             'pytz.tzfile',
             'pytz.tzinfo',
         ])

From 1cb084061c19e79e04a8e4efabd5c6a9d975286a Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 21:43:58 +0100
Subject: [PATCH 19/24] issue #275: Pin paramiko to a v2.6-compatible version.

---
 dev_requirements.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/dev_requirements.txt b/dev_requirements.txt
index 36e458f3..ece4c7ac 100644
--- a/dev_requirements.txt
+++ b/dev_requirements.txt
@@ -4,6 +4,7 @@ coverage==4.5.1
 Django==1.6.11  # Last version supporting 2.6.
 mock==2.0.0
 pytz==2012d  # Last 2.6-compat version.
+paramiko==2.3.1  # Last 2.6-compat version.
 pytest-catchlog==1.2.2
 pytest==3.1.2
 PyYAML==3.11; python_version < '2.7'

From b7eb96d116706aec495f053447fc9f39cc2932bf Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 22:07:05 +0100
Subject: [PATCH 20/24] issue #275: tests: don't explicitly specify interpreter
 path.

---
 .travis/ansible_tests.sh | 1 -
 1 file changed, 1 deletion(-)

diff --git a/.travis/ansible_tests.sh b/.travis/ansible_tests.sh
index b5162ae0..bd1af85a 100755
--- a/.travis/ansible_tests.sh
+++ b/.travis/ansible_tests.sh
@@ -45,7 +45,6 @@ echo \
     target \
     ansible_host=$DOCKER_HOSTNAME \
     ansible_port=2201 \
-    ansible_python_interpreter=/usr/bin/python2.7 \
     ansible_user=mitogen__has_sudo_nopw \
     ansible_password=has_sudo_nopw_password \
     >> ${TMPDIR}/hosts

From 4f57c59b7ea3077fd36dc38ede150498df15daf8 Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 22:43:11 +0100
Subject: [PATCH 21/24] issue #275: Don't run virtualnv test on 2.6.

---
 .../lib/modules/custom_python_detect_environment.py    |  1 +
 .../regression/issue_152__virtualenv_python_fails.yml  | 10 ++++++++--
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/tests/ansible/lib/modules/custom_python_detect_environment.py b/tests/ansible/lib/modules/custom_python_detect_environment.py
index 8f369e86..d4795422 100644
--- a/tests/ansible/lib/modules/custom_python_detect_environment.py
+++ b/tests/ansible/lib/modules/custom_python_detect_environment.py
@@ -13,6 +13,7 @@ import sys
 def main():
     module = AnsibleModule(argument_spec={})
     module.exit_json(
+        python_version=sys.version[:3],
         argv=sys.argv,
         __file__=__file__,
         argv_types=[str(type(s)) for s in sys.argv],
diff --git a/tests/ansible/regression/issue_152__virtualenv_python_fails.yml b/tests/ansible/regression/issue_152__virtualenv_python_fails.yml
index c17b3dd5..0234a0ef 100644
--- a/tests/ansible/regression/issue_152__virtualenv_python_fails.yml
+++ b/tests/ansible/regression/issue_152__virtualenv_python_fails.yml
@@ -2,20 +2,26 @@
   any_errors_fatal: true
   hosts: test-targets
   tasks:
+    - custom_python_detect_environment:
+      register: lout
 
-    # Can't use pip module because you can't fricking just create a virtualenv,
-    # must call it directly.
+    # Can't use pip module because it can't create virtualenvs, must call it
+    # directly.
     - shell: virtualenv /tmp/issue_152_virtualenv
+      when: lout.python_version != '2.6'
 
     - custom_python_detect_environment:
       vars:
         ansible_python_interpreter: /tmp/issue_152_virtualenv/bin/python
       register: out
+      when: lout.python_version != '2.6'
 
     - assert:
         that:
           - out.sys_executable == "/tmp/issue_152_virtualenv/bin/python"
+      when: lout.python_version != '2.6'
 
     - file:
         path: /tmp/issue_152_virtualenv
         state: absent
+      when: lout.python_version != '2.6'

From fb8bad934b465317d522300d9df248959e460c95 Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Sun, 24 Jun 2018 23:02:25 +0100
Subject: [PATCH 22/24] issue #275: Don't use -U in ansible_tests.sh -- forces
 paramiko upgrade

---
 .travis/ansible_tests.sh | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.travis/ansible_tests.sh b/.travis/ansible_tests.sh
index bd1af85a..ffe775fe 100755
--- a/.travis/ansible_tests.sh
+++ b/.travis/ansible_tests.sh
@@ -36,7 +36,7 @@ echo travis_fold:end:docker_setup
 
 
 echo travis_fold:start:job_setup
-pip install -U ansible=="${ANSIBLE_VERSION}"
+pip install ansible=="${ANSIBLE_VERSION}"
 cd ${TRAVIS_BUILD_DIR}/tests/ansible
 
 chmod go= ${TRAVIS_BUILD_DIR}/tests/data/docker/mitogen__has_sudo_pubkey.key

From 3a304b2458493bff3fcbd39b13e718e79de3da0a Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Mon, 25 Jun 2018 00:41:24 +0100
Subject: [PATCH 23/24] issue #275: su: add CentOS 6 style su failure

---
 mitogen/su.py | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mitogen/su.py b/mitogen/su.py
index ce81eed5..dd340554 100644
--- a/mitogen/su.py
+++ b/mitogen/su.py
@@ -58,6 +58,7 @@ class Stream(mitogen.parent.Stream):
     incorrect_prompts = (
         'su: sorry',                    # BSD
         'su: authentication failure',   # Linux
+        'su: incorrect password',       # CentOS 6
     )
 
     def construct(self, username=None, password=None, su_path=None,

From 8b398e797eb42e1814fc56c277af1a0f6bf39280 Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Mon, 25 Jun 2018 01:30:23 +0100
Subject: [PATCH 24/24] issue #275: bump ansible to 2.5.5

---
 dev_requirements.txt | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/dev_requirements.txt b/dev_requirements.txt
index ece4c7ac..faa7dab9 100644
--- a/dev_requirements.txt
+++ b/dev_requirements.txt
@@ -1,5 +1,5 @@
 -r docs/docs-requirements.txt
-ansible==2.5.2
+ansible==2.5.5
 coverage==4.5.1
 Django==1.6.11  # Last version supporting 2.6.
 mock==2.0.0