show specific undefined var errors on -v in debug (#32206)

* show specific undefined var errors on -v in debug

allows users to get more specific information about undefined errors
as they might be looking at a complex data structure and need to find
the specific leaf that has the issue

* now tests works at all verbosity levels

* updated to unicode objects

lib/ansible/plugins/action/debug.py

@@ -43,10 +43,8 @@ class ActionModule(ActionBase):
 
         result = super(ActionModule, self).run(tmp, task_vars)
 
-        verbosity = 0
         # get task verbosity
-        if 'verbosity' in self._task.args:
-            verbosity = int(self._task.args['verbosity'])
+        verbosity = int(self._task.args.get('verbosity', 0))
 
         if verbosity <= self._display.verbosity:
             if 'msg' in self._task.args:
@@ -61,8 +59,10 @@ class ActionModule(ActionBase):
                             raise AnsibleUndefinedVariable
                         # If var name is same as result, try to template it
                         results = self._templar.template("{{" + results + "}}", convert_bare=True, fail_on_undefined=True)
-                except AnsibleUndefinedVariable:
-                    results = "VARIABLE IS NOT DEFINED!"
+                except AnsibleUndefinedVariable as e:
+                    results = u"VARIABLE IS NOT DEFINED!"
+                    if self._display.verbosity > 0:
+                        results += u": %s" % to_text(e)
 
                 if isinstance(self._task.args['var'], (list, dict)):
                     # If var is a list or dict, use the type as key to display

test/integration/targets/var_blending/roles/test_var_blending/tasks/main.yml

@@ -44,7 +44,7 @@
 
 - assert:
     that:
-      - var_undefined.undefined_variable == 'VARIABLE IS NOT DEFINED!'
+      - "'VARIABLE IS NOT DEFINED!' in var_undefined.undefined_variable"
       - same_value_as_var_name.same_value_as_var_name_var == 'same_value_as_var_name_var'
 
 - name: cleanup temporary template output