Fix stderr false return value (#22845)

* ensure exit_json does not fail from stderr=False

- do a little bit of safety-checking in exit_json to not try to .splitlines() on a boolean
- remove the stderr=boolean from uri.py, this is the only spot that uses it (at least so obviously)
- add unit tests that call exit_json. These are useless because the stderr parsing is in _execute_module and is difficult to mock; deleting these tests after the commit.

* remove added unit tests per prev commit

exit_json doesn't do the param parsing, that is buried deep inside _execute_module.

lib/ansible/modules/network/basics/uri.py

@@ -425,15 +425,14 @@ def main():
         # and the filename already exists.  This allows idempotence
         # of uri executions.
         if os.path.exists(creates):
-            module.exit_json(stdout="skipped, since %s exists" % creates,
+            module.exit_json(stdout="skipped, since %s exists" % creates, changed=False, rc=0)
-                             changed=False, stderr=False, rc=0)
 
     if removes is not None:
         # do not run the command if the line contains removes=filename
         # and the filename do not exists.  This allows idempotence
         # of uri executions.
         if not os.path.exists(removes):
-            module.exit_json(stdout="skipped, since %s does not exist" % removes, changed=False, stderr=False, rc=0)
+            module.exit_json(stdout="skipped, since %s does not exist" % removes, changed=False, rc=0)
 
     # Make the request
     resp, content, dest = uri(module, url, dest, body, body_format, method,

lib/ansible/plugins/action/__init__.py

@@ -514,7 +514,7 @@ class ActionBase(with_metaclass(ABCMeta, object)):
         3 = its a directory, not a file
         4 = stat module failed, likely due to not finding python
         '''
-        x = "0"  # unknown error has occured
+        x = "0"  # unknown error has occurred
         try:
             remote_stat = self._execute_remote_stat(path, all_vars, follow=follow)
             if remote_stat['exists'] and remote_stat['isdir']:
@@ -754,9 +754,13 @@ class ActionBase(with_metaclass(ABCMeta, object)):
 
         # pre-split stdout/stderr into lines if needed
         if 'stdout' in data and 'stdout_lines' not in data:
-            data['stdout_lines'] = data.get('stdout', u'').splitlines()
+            # if the value is 'False', a default won't catch it.
+            txt = data.get('stdout', None) or u''
+            data['stdout_lines'] = txt.splitlines()
         if 'stderr' in data and 'stderr_lines' not in data:
-            data['stderr_lines'] = data.get('stderr', u'').splitlines()
+            # if the value is 'False', a default won't catch it.
+            txt = data.get('stderr', None) or u''
+            data['stderr_lines'] = txt.splitlines()
 
         display.debug("done with _execute_module (%s, %s)" % (module_name, module_args))
         return data