Set HostVars._variable_manager's attrs (#65508)

When HostVars are part of the data that goes through (de)serialization
when being passed from a worker process to the main process, its
variable manager reference loses some of its attributes due to the
implementation of __getstate__ and __setstate__ (perf utilization).
Since HostVars already has those attributes, use __setstate__ to assign
them.

Fixes #65365

changelogs/fragments/65365-fix-tb-printing-hostvars.yml

@@ -0,0 +1,2 @@
+bugfixes:
+  - Fix traceback when printing ``HostVars`` on native Jinja2 (https://github.com/ansible/ansible/issues/65365)

lib/ansible/vars/hostvars.py

@@ -49,7 +49,6 @@ class HostVars(Mapping):
     ''' A special view of vars_cache that adds values from the inventory when needed. '''
 
     def __init__(self, inventory, variable_manager, loader):
-        self._lookup = dict()
         self._inventory = inventory
         self._loader = loader
         self._variable_manager = variable_manager
@@ -77,6 +76,19 @@ class HostVars(Mapping):
 
         return self._variable_manager.get_vars(host=host, include_hostvars=False)
 
+    def __setstate__(self, state):
+        self.__dict__.update(state)
+
+        # Methods __getstate__ and __setstate__ of VariableManager do not
+        # preserve _loader and _hostvars attributes to improve pickle
+        # performance and memory utilization. Since HostVars holds values
+        # of those attributes already, assign them if needed.
+        if self._variable_manager._loader is None:
+            self._variable_manager._loader = self._loader
+
+        if self._variable_manager._hostvars is None:
+            self._variable_manager._hostvars = self
+
     def __getitem__(self, host_name):
         data = self.raw_get(host_name)
         if isinstance(data, AnsibleUndefined):

lib/ansible/vars/manager.py

@@ -133,6 +133,8 @@ class VariableManager:
         self._inventory = data.get('inventory', None)
         self._options_vars = data.get('options_vars', dict())
         self.safe_basedir = data.get('safe_basedir', False)
+        self._loader = None
+        self._hostvars = None
 
     @property
     def extra_vars(self):

test/integration/targets/jinja2_native_types/inventory.jinja2_native_types

@@ -0,0 +1 @@
+host1

test/integration/targets/jinja2_native_types/runme.sh

@@ -4,3 +4,4 @@ set -eux
 
 ANSIBLE_JINJA2_NATIVE=1 ansible-playbook -i inventory.jinja2_native_types runtests.yml -v "$@"
 ANSIBLE_JINJA2_NATIVE=1 ansible-playbook -i inventory.jinja2_native_types --vault-password-file test_vault_pass test_vault.yml -v "$@"
+ANSIBLE_JINJA2_NATIVE=1 ansible-playbook -i inventory.jinja2_native_types test_hostvars.yml -v "$@"

test/integration/targets/jinja2_native_types/test_hostvars.yml

@@ -0,0 +1,10 @@
+- hosts: host1
+  gather_facts: no
+  tasks:
+    - name: Print vars
+      debug:
+        var: vars
+
+    - name: Print hostvars
+      debug:
+        var: hostvars