template lookup: restore variables between calls (#55126)

* template lookup: restore variables between calls

Fixes #55113

* Address issues from the review

changelogs/fragments/55113-template-lookup-restore-vars.yaml

@@ -0,0 +1,2 @@
+bugfixes:
+  - template lookup - restore variables between calls (https://github.com/ansible/ansible/issues/55113)

lib/ansible/plugins/lookup/template.py

@@ -45,6 +45,7 @@ _raw:
    description: file(s) content after templating
 """
 
+from copy import deepcopy
 import os
 
 from ansible.errors import AnsibleError
@@ -67,6 +68,8 @@ class LookupModule(LookupBase):
         variable_start_string = kwargs.get('variable_start_string', None)
         variable_end_string = kwargs.get('variable_end_string', None)
 
+        old_vars = self._templar._available_variables
+
         for term in terms:
             display.debug("File lookup term: %s" % term)
 
@@ -99,7 +102,7 @@ class LookupModule(LookupBase):
                 # plus some added by ansible (e.g., template_{path,mtime}),
                 # plus anything passed to the lookup with the template_vars=
                 # argument.
-                vars = variables.copy()
+                vars = deepcopy(variables)
                 vars.update(generate_ansible_template_vars(lookupfile))
                 vars.update(lookup_template_vars)
                 self._templar.set_available_variables(vars)
@@ -107,8 +110,12 @@ class LookupModule(LookupBase):
                 # do the templating
                 res = self._templar.template(template_data, preserve_trailing_newlines=True,
                                              convert_data=convert_data_p, escape_backslashes=False)
+
                 ret.append(res)
             else:
                 raise AnsibleError("the template file %s could not be found for the lookup" % term)
 
+        # restore old variables
+        self._templar.set_available_variables(old_vars)
+
         return ret