Merge remote-tracking branch 'origin/issue590'

* origin/issue590:
  issue #590: disable distro test on vanilla
  ci: Ansible 2.8 jobs aren't running against all host types.
  tests: Py3.x fix.
  issue #590: fix test for <2.8 Ansibles.
  tests: Py3.x fix.
  issue #590: actually run Ansible test.
  tests: Py3.x fix.
  master: sysconfig did not exist until 2.7.
  tests: rearrange test modules again, they're used in multiple places
  module_finder_test: mask one more difference between unit2 vs. direct start
  master: fix _is_stdlib_path() failure on Ubuntu.
  issue #590: add dummy package for new test.
  issue #590: add FinderMethod docstrings.
  issue #590: update comment to indicate the hack is permanent
  issue #590: move example modules to module_finder/, fix/add tests
  issue #590: refactor ModuleFinder and teach it a new special case.
  issue #590: Ansible test for module_utils.distro use.
  issue #590: teach importer to handle self-replacing modules

Author: dw

.ci/azure-pipelines.yml

@@ -92,10 +92,8 @@ jobs:
         python.version: '2.7'
         MODE: ansible
         VER: 2.8.0
-        DISTROS: debian
 
       Ansible_280_35:
         python.version: '3.5'
         MODE: ansible
         VER: 2.8.0
-        DISTROS: debian

ansible_mitogen/runner.py

@@ -763,7 +763,16 @@ def _setup_imports(self):
             try:
                 mitogen.core.import_module(fullname)
             except ImportError:
-                # TODO: this is a huge hack to work around issue #590.
+                # #590: Ansible 2.8 module_utils.distro is a package that
+                # replaces itself in sys.modules with a non-package during
+                # import. Prior to replacement, it is a real package containing
+                # a '_distro' submodule which is used on 2.x. Given a 2.x
+                # controller and 3.x target, the import hook never needs to run
+                # again before this replacement occurs, and 'distro' is
+                # replaced with a module from the stdlib. In this case as this
+                # loop progresses to the next entry and attempts to preload
+                # 'distro._distro', the import mechanism will fail. So here we
+                # silently ignore any failure for it.
                 if fullname != 'ansible.module_utils.distro._distro':
                     raise
 

docs/changelog.rst

@@ -30,6 +30,12 @@ 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.
+
 
 Thanks!
 ~~~~~~~

mitogen/core.py

@@ -1355,7 +1355,10 @@ def load_module(self, fullname):
             exec(code, vars(mod))
         else:
             exec('exec code in vars(mod)')
-        return mod
+
+        # #590: if a module replaces itself in sys.modules during import, below
+        # is necessary. This matches PyImport_ExecCodeModuleEx()
+        return sys.modules.get(fullname, mod)
 
     def get_filename(self, fullname):
         if fullname in self._cache: