fix.patch

--- a/template/template.py	2016-05-04 15:18:58.000000000 +0000
+++ b/template/template.py	2016-05-04 15:25:04.918007068 +0000
@@ -33,5 +33,7 @@
     '''

     def new_context(self, vars=None, shared=False, locals=None):
-        return jinja2.runtime.Context(self.environment, vars.add_locals(locals), self.name, self.blocks)
+        if vars is not None:
+            vars = vars.add_locals(locals)
+        return jinja2.runtime.Context(self.environment, vars, self.name, self.blocks)

macros.j2

{% macro hello() %}
hello, world!
{% endmacro %}

output_original.log

root@677539bf52ab:~# ansible-playbook t.yml -DCvv
Using /etc/ansible/ansible.cfg as config file
 [WARNING]: provided hosts list is empty, only localhost is available


PLAYBOOK: t.yml ****************************************************************
1 plays in t.yml

PLAY [localhost] ***************************************************************

TASK [template] ****************************************************************
task path: /root/t.yml:4
fatal: [localhost]: FAILED! => {"changed": false, "failed": true, "msg": "AttributeError: 'NoneType' object has no attribute 'add_locals'"}

NO MORE HOSTS LEFT *************************************************************
	to retry, use: --limit @t.retry

PLAY RECAP *********************************************************************
localhost                  : ok=0    changed=0    unreachable=0    failed=1

output_patched.log

root@677539bf52ab:~# ansible-playbook t.yml -DCvv
Using /etc/ansible/ansible.cfg as config file
 [WARNING]: provided hosts list is empty, only localhost is available


PLAYBOOK: t.yml ****************************************************************
1 plays in t.yml

PLAY [localhost] ***************************************************************

TASK [template] ****************************************************************
task path: /root/t.yml:4
changed: [localhost] => {"changed": true, "diff": {"after": "hello, world!\n", "after_header": "dynamically generated", "before": ""}}
--- before
+++ after: dynamically generated
@@ -0,0 +1 @@
+hello, world!


PLAY RECAP *********************************************************************
localhost                  : ok=1    changed=1    unreachable=0    failed=0

t.j2

{% import 'macros.j2' as macros %}
{{ macros.hello() }}

t.yml

- hosts: localhost
  gather_facts: false
  tasks:
  - template:
      src: t.j2
      dest: /tmp/foo