Make sure files loaded by template action are decoded properly

Fixes #11247

lib/ansible/plugins/action/template.py

@@ -25,7 +25,7 @@ import time
 from ansible import constants as C
 from ansible.plugins.action import ActionBase
 from ansible.utils.hashing import checksum_s
-from ansible.utils.unicode import to_bytes
+from ansible.utils.unicode import to_bytes, to_unicode
 
 class ActionModule(ActionBase):
 
@@ -100,34 +100,34 @@ class ActionModule(ActionBase):
         # template the source data locally & get ready to transfer
         try:
             with open(source, 'r') as f:
-                template_data = f.read()
+                template_data = to_unicode(f.read())
 
             try:
                 template_uid = pwd.getpwuid(os.stat(source).st_uid).pw_name
             except:
                 template_uid = os.stat(source).st_uid
 
-            vars = task_vars.copy()
-            vars['template_host']     = os.uname()[1]
-            vars['template_path']     = source
-            vars['template_mtime']    = datetime.datetime.fromtimestamp(os.path.getmtime(source))
-            vars['template_uid']      = template_uid
-            vars['template_fullpath'] = os.path.abspath(source)
-            vars['template_run_date'] = datetime.datetime.now()
+            temp_vars = task_vars.copy()
+            temp_vars['template_host']     = os.uname()[1]
+            temp_vars['template_path']     = source
+            temp_vars['template_mtime']    = datetime.datetime.fromtimestamp(os.path.getmtime(source))
+            temp_vars['template_uid']      = template_uid
+            temp_vars['template_fullpath'] = os.path.abspath(source)
+            temp_vars['template_run_date'] = datetime.datetime.now()
 
             managed_default = C.DEFAULT_MANAGED_STR
             managed_str = managed_default.format(
-                host = vars['template_host'],
-                uid  = vars['template_uid'],
-                file = to_bytes(vars['template_path'])
+                host = temp_vars['template_host'],
+                uid  = temp_vars['template_uid'],
+                file = to_bytes(temp_vars['template_path'])
             )
-            vars['ansible_managed'] = time.strftime(
+            temp_vars['ansible_managed'] = time.strftime(
                 managed_str,
                 time.localtime(os.path.getmtime(source))
             )
 
             old_vars = self._templar._available_variables
-            self._templar.set_available_variables(vars)
+            self._templar.set_available_variables(temp_vars)
             resultant = self._templar.template(template_data, preserve_trailing_newlines=True)
             self._templar.set_available_variables(old_vars)
         except Exception as e: