ansible: don't crash when adhoc tries to run a missing module.

ansible-playbook prints a separate error during parsing stage, adhoc
performs no such check.

ansible_mitogen/planner.py

@@ -55,6 +55,7 @@ import ansible_mitogen.target
 LOG = logging.getLogger(__name__)
 NO_METHOD_MSG = 'Mitogen: no invocation method found for: '
 NO_INTERPRETER_MSG = 'module (%s) is missing interpreter line'
+NO_MODULE_MSG = 'The module %s was not found in configured module paths.'
 
 
 class Invocation(object):
@@ -393,6 +394,9 @@ _planners = [
 
 def get_module_data(name):
     path = ansible_mitogen.loaders.module_loader.find_plugin(name, '')
+    if path is None:
+        raise ansible.errors.AnsibleError(NO_MODULE_MSG % (name,))
+
     with open(path, 'rb') as fp:
         source = fp.read()
     return mitogen.core.to_text(path), source

tests/ansible/integration/runner/all.yml

@@ -15,3 +15,4 @@
 - import_playbook: environment_isolation.yml
 - import_playbook: etc_environment.yml
 - import_playbook: forking_behaviour.yml
+- import_playbook: missing_module.yml

tests/ansible/integration/runner/missing_module.yml

@@ -0,0 +1,15 @@
+
+- name: integration/runner/missing_module.yml
+  hosts: test-targets
+  connection: local
+  tasks:
+    - connection: local
+      command: ansible -i localhost, localhost -m missing_module
+      args:
+        chdir: ../..
+      register: out
+      ignore_errors: true
+
+    - assert:
+        that: |
+          'The module missing_module was not found in configured module paths.' in out.stdout