Merge pull request #12457 from ansible/warn-if-core-modules-not-present

Detect if core modules aren't installed and warn if that is the  case

lib/ansible/parsing/mod_args.py

@@ -275,7 +275,14 @@ class ModuleArgsParser:
 
         # if we didn't see any module in the task at all, it's not a task really
         if action is None:
-            raise AnsibleParserError("no action detected in task", obj=self._task_ds)
+            if 'ping' not in module_loader:
+                raise AnsibleParserError("The requested action was not found in configured module paths. "
+                        "Additionally, core modules are missing. If this is a checkout, "
+                        "run 'git submodule update --init --recursive' to correct this problem.",
+                        obj=self._task_ds)
+
+            else:
+                raise AnsibleParserError("no action detected in task", obj=self._task_ds)
         elif args.get('_raw_params', '') != '' and action not in RAW_PARAM_MODULES:
             templar = Templar(loader=None)
             raw_params = args.pop('_raw_params')