deprecate all bare variable conversions (not debug)

now deprecation message appears with variable name in all spots where this occurs
debug's var= option is excluded as this is only place where bare variables shold actually
be accepted.

lib/ansible/plugins/action/debug.py

@@ -46,7 +46,7 @@ class ActionModule(ActionBase):
 
         elif 'var' in self._task.args:
             try:
-                results = self._templar.template(self._task.args['var'], convert_bare=True, fail_on_undefined=True)
+                results = self._templar.template(self._task.args['var'], convert_bare=True, fail_on_undefined=True, bare_deprecated=False)
                 if results == self._task.args['var']:
                     raise AnsibleUndefinedVariable
             except AnsibleUndefinedVariable:

lib/ansible/template/__init__.py

@@ -46,6 +46,12 @@ except ImportError:
 
 from numbers import Number
 
+try:
+    from __main__ import display
+except ImportError:
+    from ansible.utils.display import Display
+    display = Display()
+
 __all__ = ['Templar']
 
 # A regex for checking to see if a variable we're trying to
@@ -269,7 +275,7 @@ class Templar:
         self._available_variables = variables
         self._cached_result       = {}
 
-    def template(self, variable, convert_bare=False, preserve_trailing_newlines=True, escape_backslashes=True, fail_on_undefined=None, overrides=None, convert_data=True, static_vars = [''], cache = True):
+    def template(self, variable, convert_bare=False, preserve_trailing_newlines=True, escape_backslashes=True, fail_on_undefined=None, overrides=None, convert_data=True, static_vars = [''], cache = True, bare_deprecated=True):
         '''
         Templates (possibly recursively) any given data as input. If convert_bare is
         set to True, the given data will be wrapped as a jinja2 variable ('{{foo}}')
@@ -290,7 +296,7 @@ class Templar:
 
         try:
             if convert_bare:
-                variable = self._convert_bare_variable(variable)
+                variable = self._convert_bare_variable(variable, bare_deprecated=bare_deprecated)
 
             if isinstance(variable, string_types):
                 result = variable
@@ -366,7 +372,7 @@ class Templar:
         '''
         return self.environment.block_start_string in data or self.environment.variable_start_string in data
 
-    def _convert_bare_variable(self, variable):
+    def _convert_bare_variable(self, variable, bare_deprecated):
         '''
         Wraps a bare string, which may have an attribute portion (ie. foo.bar)
         in jinja2 variable braces so that it is evaluated properly.
@@ -376,6 +382,9 @@ class Templar:
             contains_filters = "|" in variable
             first_part = variable.split("|")[0].split(".")[0].split("[")[0]
             if (contains_filters or first_part in self._available_variables) and self.environment.variable_start_string not in variable:
+                if bare_deprecated:
+                     display.deprecated("Using bare variables is deprecated. Update your playbooks so that the environment value uses the full variable syntax ('%s%s%s')" %
+                        (self.environment.variable_start_string, variable, self.environment.variable_end_string))
                 return "%s%s%s" % (self.environment.variable_start_string, variable, self.environment.variable_end_string)
 
         # the variable didn't meet the conditions to be converted,