remove the stdin return value from connection plugin exec_command() methods

The value was useless -- unused by the callers and always hardcoded to
the empty string.

lib/ansible/plugins/action/__init__.py

@@ -467,7 +467,7 @@ class ActionBase:
             cmd = self._play_context.make_become_cmd(cmd, executable=executable)
 
         self._display.debug("executing the command %s through the connection" % cmd)
-        rc, stdin, stdout, stderr = self._connection.exec_command(cmd, tmp, in_data=in_data, sudoable=sudoable)
+        rc, stdout, stderr = self._connection.exec_command(cmd, tmp, in_data=in_data, sudoable=sudoable)
         self._display.debug("command execution done")
 
         if not isinstance(stdout, string_types):

lib/ansible/plugins/connection/__init__.py

@@ -123,7 +123,11 @@ class ConnectionBase(with_metaclass(ABCMeta, object)):
     @ensure_connect
     @abstractmethod
     def exec_command(self, cmd, tmp_path, in_data=None, executable=None, sudoable=True):
-        """Run a command on the remote host"""
+        """Run a command on the remote host
+
+        :returns: a tuple of (return code, stdout, stderr)  The return code is
+            an int while stdout and stderr are both byte strings.
+        """
         pass
 
     @ensure_connect

lib/ansible/plugins/connection/accelerate.py

@@ -281,7 +281,7 @@ class Connection(ConnectionBase):
                 vvvv("%s: received the response" % self.host)
                 break
 
-        return (response.get('rc',None), '', response.get('stdout',''), response.get('stderr',''))
+        return (response.get('rc', None), response.get('stdout', ''), response.get('stderr', ''))
 
     def put_file(self, in_path, out_path):
 

lib/ansible/plugins/connection/chroot.py

@@ -116,7 +116,7 @@ class Connection(ConnectionBase):
         p = self._buffered_exec_command(cmd, tmp_path, become_user, sudoable, executable, in_data)
 
         stdout, stderr = p.communicate()
-        return (p.returncode, '', stdout, stderr)
+        return (p.returncode, stdout, stderr)
 
     def put_file(self, in_path, out_path):
         ''' transfer a file from local to chroot '''

lib/ansible/plugins/connection/docker.py

@@ -111,7 +111,7 @@ class Connection(ConnectionBase):
                              stdout=subprocess.PIPE, stderr=subprocess.PIPE)
 
         stdout, stderr = p.communicate()
-        return (p.returncode, '', stdout, stderr)
+        return (p.returncode, stdout, stderr)
 
     # Docker doesn't have native support for copying files into running
     # containers, so we use docker exec to implement this

lib/ansible/plugins/connection/funcd.py

@@ -65,7 +65,7 @@ class Connection(object):
         # totally ignores privlege escalation
         vvv("EXEC %s" % (cmd), host=self.host)
         p = self.client.command.run(cmd)[self.host]
-        return (p[0], '', p[1], p[2])
+        return (p[0], p[1], p[2])
 
     def _normalize_path(self, path, prefix):
         if not path.startswith(os.path.sep):

lib/ansible/plugins/connection/jail.py

@@ -133,7 +133,7 @@ class Connection(object):
         p = self._buffered_exec_command(cmd, tmp_path, become_user, sudoable, executable, in_data)
 
         stdout, stderr = p.communicate()
-        return (p.returncode, '', stdout, stderr)
+        return (p.returncode, stdout, stderr)
 
     def put_file(self, in_path, out_path):
         ''' transfer a file from local to jail '''

lib/ansible/plugins/connection/libvirt_lxc.py

@@ -88,7 +88,7 @@ class Connection(object):
                              stdout=subprocess.PIPE, stderr=subprocess.PIPE)
 
         stdout, stderr = p.communicate()
-        return (p.returncode, '', stdout, stderr)
+        return (p.returncode, stdout, stderr)
 
     def _normalize_path(self, path, prefix):
         if not path.startswith(os.path.sep):

lib/ansible/plugins/connection/local.py

@@ -98,7 +98,7 @@ class Connection(ConnectionBase):
         self._display.debug("done communicating")
 
         self._display.debug("done with local.exec_command()")
-        return (p.returncode, '', stdout, stderr)
+        return (p.returncode, stdout, stderr)
 
     def put_file(self, in_path, out_path):
         ''' transfer a file from local to local '''

lib/ansible/plugins/connection/paramiko_ssh.py

@@ -256,7 +256,7 @@ class Connection(ConnectionBase):
         stdout = ''.join(chan.makefile('rb', bufsize))
         stderr = ''.join(chan.makefile_stderr('rb', bufsize))
 
-        return (chan.recv_exit_status(), '', no_prompt_out + stdout, no_prompt_out + stderr)
+        return (chan.recv_exit_status(), no_prompt_out + stdout, no_prompt_out + stderr)
 
     def put_file(self, in_path, out_path):
         ''' transfer a file from local to remote '''

lib/ansible/plugins/connection/ssh.py

@@ -304,7 +304,7 @@ class Connection(ConnectionBase):
 
         (returncode, stdout, stderr) = self._run(cmd, in_data, sudoable=sudoable)
 
-        return (returncode, '', stdout, stderr)
+        return (returncode, stdout, stderr)
 
     def put_file(self, in_path, out_path):
         ''' transfer a file from local to remote '''

lib/ansible/plugins/connection/winrm.py

@@ -202,7 +202,7 @@ class Connection(ConnectionBase):
             raise AnsibleError("failed to exec cmd %s" % cmd)
         result.std_out = to_unicode(result.std_out)
         result.std_err = to_unicode(result.std_err)
-        return (result.status_code, '', result.std_out, result.std_err)
+        return (result.status_code, result.std_out, result.std_err)
 
     def put_file(self, in_path, out_path):
         super(Connection, self).put_file(in_path, out_path)

lib/ansible/plugins/connection/zone.py

@@ -146,7 +146,7 @@ class Connection(object):
         p = self._buffered_exec_command(cmd, tmp_path, become_user, sudoable, executable, in_data)
 
         stdout, stderr = p.communicate()
-        return (p.returncode, '', stdout, stderr)
+        return (p.returncode, stdout, stderr)
 
     def put_file(self, in_path, out_path):
         ''' transfer a file from local to zone '''

test/units/plugins/action/test_action.py

@@ -32,7 +32,7 @@ class TestActionBase(unittest.TestCase):
     def test_sudo_only_if_user_differs(self):
         play_context = PlayContext()
         action_base = ActionBase(None, None, play_context, None, None, None)
-        action_base._connection = Mock(exec_command=Mock(return_value=(0, '', '', '')))
+        action_base._connection = Mock(exec_command=Mock(return_value=(0, '', '')))
 
         play_context.become = True
         play_context.become_user = play_context.remote_user = 'root'