From 0b7fd3f2904f3f9af0293deefad7e9ca361f226f Mon Sep 17 00:00:00 2001
From: David Wilson <dw@botanicus.net>
Date: Mon, 3 Jun 2019 02:31:43 +0100
Subject: [PATCH] issue #591: ansible: restore CWD prior to AnsibleModule
 initialization.

---
 ansible_mitogen/runner.py                     | 11 ++++++++++
 docs/changelog.rst                            | 11 ++++++++++
 .../lib/modules/custom_python_os_getcwd.py    | 14 +++++++++++++
 tests/ansible/regression/all.yml              |  1 +
 .../issue_591__setuptools_cwd_crash.yml       | 20 +++++++++++++++++++
 5 files changed, 57 insertions(+)
 create mode 100644 tests/ansible/lib/modules/custom_python_os_getcwd.py
 create mode 100644 tests/ansible/regression/issue_591__setuptools_cwd_crash.yml

diff --git a/ansible_mitogen/runner.py b/ansible_mitogen/runner.py
index 8dbddadd..05bc55c0 100644
--- a/ansible_mitogen/runner.py
+++ b/ansible_mitogen/runner.py
@@ -344,11 +344,22 @@ class Runner(object):
             env.update(self.env)
         self._env = TemporaryEnvironment(env)
 
+    def _revert_cwd(self):
+        """
+        #591: make a best-effort attempt to return to :attr:`good_temp_dir`.
+        """
+        try:
+            os.chdir(self.good_temp_dir)
+        except OSError:
+            LOG.debug('%r: could not restore CWD to %r',
+                      self, self.good_temp_dir)
+
     def revert(self):
         """
         Revert any changes made to the process after running a module. The base
         implementation simply restores the original environment.
         """
+        self._revert_cwd()
         self._env.revert()
         self.revert_temp_dir()
 
diff --git a/docs/changelog.rst b/docs/changelog.rst
index 4a3a5612..1e4c7e18 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -30,18 +30,29 @@ Enhancements
   <https://docs.ansible.com/ansible/latest/plugins/become.html>`_
   functionality, which will be addressed in a future release.
 
+
 Fixes
 ^^^^^
 
 * `#590 <https://github.com/dw/mitogen/issues/590>`_: the importer can handle
   modules that replace themselves in :mod:`sys.modules` during import.
 
+* `#591 <https://github.com/dw/mitogen/issues/591>`_: the target's current
+  working directory is restored to a known-existent directory between tasks to
+  ensure :func:`os.getcwd` will not fail when called, in the same way that
+  :class:`AnsibleModule` restores it during initialization. However this
+  restore happens before the module ever executes, ensuring any code that calls
+  :func:`os.getcwd` prior to :class:`AnsibleModule` initialization, such as the
+  Ansible 2.7 ``pip`` module, cannot fail due to the behavior of a prior task.
+
 
 Thanks!
 ~~~~~~~
 
 Mitogen would not be possible without the support of users. A huge thanks for
 bug reports, testing, features and fixes in this release contributed by
+`Anton Markelov <https://github.com/strangeman>`_,
+`Nigel Metheringham <https://github.com/nigelm>`_,
 `Orion Poplawski <https://github.com/opoplawski>`_, and
 `Ulrich Schreiner <https://github.com/ulrichSchreiner>`_.
 
diff --git a/tests/ansible/lib/modules/custom_python_os_getcwd.py b/tests/ansible/lib/modules/custom_python_os_getcwd.py
new file mode 100644
index 00000000..7fe3fd1b
--- /dev/null
+++ b/tests/ansible/lib/modules/custom_python_os_getcwd.py
@@ -0,0 +1,14 @@
+#!/usr/bin/python
+# #591: call os.getcwd() before AnsibleModule ever gets a chance to fix up the
+# process environment.
+
+import os
+
+try:
+    import json
+except ImportError:
+    import simplejson as json
+
+print(json.dumps({
+    'cwd': os.getcwd()
+}))
diff --git a/tests/ansible/regression/all.yml b/tests/ansible/regression/all.yml
index 62606b00..32852942 100644
--- a/tests/ansible/regression/all.yml
+++ b/tests/ansible/regression/all.yml
@@ -9,3 +9,4 @@
 - include: issue_177__copy_module_failing.yml
 - include: issue_332_ansiblemoduleerror_first_occurrence.yml
 - include: issue_590__sys_modules_crap.yml
+- include: issue_591__setuptools_cwd_crash.yml
diff --git a/tests/ansible/regression/issue_591__setuptools_cwd_crash.yml b/tests/ansible/regression/issue_591__setuptools_cwd_crash.yml
new file mode 100644
index 00000000..cbd65193
--- /dev/null
+++ b/tests/ansible/regression/issue_591__setuptools_cwd_crash.yml
@@ -0,0 +1,20 @@
+# #591: process CWD is not reset before start of module execution. This is
+# usually fine, except for modules importing setuptools early, which attempts
+# to call getcwd() before AnsibleModule has had a chance to clean up the
+# process environment.
+
+- hosts: test-targets
+  tasks:
+  - meta: end_play
+    when: not is_mitogen
+
+  - custom_python_run_script:
+      script: |
+        import os
+        os.chdir(module.tmpdir)
+
+  # Will crash if process has a nonexistent CWD.
+  - custom_python_os_getcwd:
+      script: |
+        import os
+        self._connection.get_chain().call(os.getcwd)