Make the loop variable (item by default) settable per task

Required for include+with* tasks which may include files that also
have tasks containing a with* loop.

Fixes #12736

lib/ansible/playbook/attribute.py

@@ -23,7 +23,7 @@ from copy import deepcopy
 
 class Attribute:
 
-    def __init__(self, isa=None, private=False, default=None, required=False, listof=None, priority=0, always_post_validate=False):
+    def __init__(self, isa=None, private=False, default=None, required=False, listof=None, priority=0, class_type=None, always_post_validate=False):
 
         self.isa = isa
         self.private = private
@@ -31,6 +31,7 @@ class Attribute:
         self.required = required
         self.listof = listof
         self.priority = priority
+        self.class_type = class_type
         self.always_post_validate = always_post_validate
 
         if default is not None and self.isa in ('list', 'dict', 'set'):

lib/ansible/playbook/base.py

@@ -304,6 +304,8 @@ class Base:
                 method = getattr(self, '_post_validate_%s' % name, None)
                 if method:
                     value = method(attribute, getattr(self, name), templar)
+                elif attribute.isa == 'class':
+                    value = getattr(self, name)
                 else:
                     # if the attribute contains a variable, template it now
                     value = templar.template(getattr(self, name))
@@ -363,6 +365,10 @@ class Base:
                             value = dict()
                         elif not isinstance(value, dict):
                             raise TypeError("%s is not a dictionary" % value)
+                    elif attribute.isa == 'class':
+                        if not isinstance(value, attribute.class_type):
+                            raise TypeError("%s is not a valid %s (got a %s instead)" % (name, attribute.class_type, type(value)))
+                        value.post_validate(templar=templar)
 
                 # and assign the massaged value back to the attribute field
                 setattr(self, name, value)

lib/ansible/playbook/included_file.py

@@ -80,8 +80,11 @@ class IncludedFile:
                     templar = Templar(loader=loader, variables=task_vars)
 
                     include_variables = include_result.get('include_variables', dict())
-                    if 'item' in include_result:
-                        task_vars['item'] = include_variables['item'] = include_result['item']
+                    loop_var = 'item'
+                    if res._task.loop_control:
+                        loop_var = res._task.loop_control.loop_var or 'item'
+                    if loop_var in include_result:
+                        task_vars[loop_var] = include_variables[loop_var] = include_result[loop_var]
 
                     if original_task:
                         if original_task.static:

lib/ansible/playbook/loop_control.py

@@ -0,0 +1,40 @@
+# (c) 2012-2014, Michael DeHaan <michael.dehaan@gmail.com>
+#
+# This file is part of Ansible
+#
+# Ansible is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Ansible is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
+
+# Make coding more python3-ish
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+import itertools
+
+from ansible.compat.six import string_types
+from ansible.errors import AnsibleError
+from ansible.playbook.attribute import FieldAttribute
+from ansible.playbook.base import Base
+
+class LoopControl(Base):
+
+    _loop_var = FieldAttribute(isa='str')
+
+    def __init__(self):
+        super(LoopControl, self).__init__()
+
+    @staticmethod
+    def load(data, variable_manager=None, loader=None):
+        t = LoopControl()
+        return t.load_data(data, variable_manager=variable_manager, loader=loader)
+

lib/ansible/playbook/task.py

@@ -32,6 +32,7 @@ from ansible.playbook.base import Base
 from ansible.playbook.become import Become
 from ansible.playbook.block import Block
 from ansible.playbook.conditional import Conditional
+from ansible.playbook.loop_control import LoopControl
 from ansible.playbook.role import Role
 from ansible.playbook.taggable import Taggable
 
@@ -78,6 +79,7 @@ class Task(Base, Conditional, Taggable, Become):
     _first_available_file = FieldAttribute(isa='list')
     _loop                 = FieldAttribute(isa='string', private=True)
     _loop_args            = FieldAttribute(isa='list', private=True)
+    _loop_control         = FieldAttribute(isa='class', class_type=LoopControl)
     _name                 = FieldAttribute(isa='string', default='')
     _notify               = FieldAttribute(isa='list')
     _poll                 = FieldAttribute(isa='int')
@@ -220,6 +222,16 @@ class Task(Base, Conditional, Taggable, Become):
 
         return super(Task, self).preprocess_data(new_ds)
 
+    def _load_loop_control(self, attr, ds):
+        if not isinstance(ds, dict):
+           raise AnsibleParserError(
+               "the `loop_control` value must be specified as a dictionary and cannot " \
+               "be a variable itself (though it can contain variables)",
+               obj=ds,
+           )
+
+        return LoopControl.load(data=ds, variable_manager=self._variable_manager, loader=self._loader)
+
     def post_validate(self, templar):
         '''
         Override of base class post_validate, to also do final validation on