add jinja2 global to reserved names (#71088)

* add jinja2 global to reserved names

  also allow expansion by additional context provided from caller

  fixes #41955

Co-authored-by: Abhijeet Kasurde <akasurde@redhat.com>

changelogs/fragments/moar_reserved_vars.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - Handle more varnames that can create conflicts, expand a function in general, handle jinja2 globals in particular (https://github.com/ansible/ansible/issues/41955).

lib/ansible/executor/task_queue_manager.py

@@ -31,13 +31,10 @@ from ansible.executor.stats import AggregateStats
 from ansible.executor.task_result import TaskResult
 from ansible.module_utils.six import string_types
 from ansible.module_utils._text import to_text, to_native
-from ansible.playbook.block import Block
 from ansible.playbook.play_context import PlayContext
 from ansible.plugins.loader import callback_loader, strategy_loader, module_loader
 from ansible.plugins.callback import CallbackBase
 from ansible.template import Templar
-from ansible.utils.collection_loader import AnsibleCollectionRef
-from ansible.utils.helpers import pct_to_int
 from ansible.vars.hostvars import HostVars
 from ansible.vars.reserved import warn_if_reserved
 from ansible.utils.display import Display
@@ -197,8 +194,8 @@ class TaskQueueManager:
             self.load_callbacks()
 
         all_vars = self._variable_manager.get_vars(play=play)
-        warn_if_reserved(all_vars)
         templar = Templar(loader=self._loader, variables=all_vars)
+        warn_if_reserved(all_vars, templar.environment.globals.keys())
 
         new_play = play.copy()
         new_play.post_validate(templar)

lib/ansible/vars/reserved.py

@@ -65,12 +65,17 @@ def get_reserved_names(include_private=True):
     return result
 
 
-def warn_if_reserved(myvars):
+def warn_if_reserved(myvars, additional=None):
     ''' this function warns if any variable passed conflicts with internally reserved names '''
 
+    if additional is None:
+        reserved = _RESERVED_NAMES
+    else:
+        reserved = _RESERVED_NAMES.union(additional)
+
     varnames = set(myvars)
     varnames.discard('vars')  # we add this one internally, so safe to ignore
-    for varname in varnames.intersection(_RESERVED_NAMES):
+    for varname in varnames.intersection(reserved):
         display.warning('Found variable using reserved name: %s' % varname)
 
 

test/integration/targets/var_reserved/aliases

@@ -0,0 +1 @@
+shippable/posix/group2

test/integration/targets/var_reserved/reserved_varname_warning.yml

@@ -0,0 +1,6 @@
+- hosts: localhost
+  gather_facts: false
+  vars:
+    lipsum: jinja2 uses me internally
+  tasks:
+    - debug:

test/integration/targets/var_reserved/runme.sh

@@ -0,0 +1,5 @@
+#!/usr/bin/env bash
+
+set -eux
+
+ansible-playbook reserved_varname_warning.yml "$@" 2>&1| grep 'Found variable using reserved name: lipsum'