Fix user data unpacking in noetic

[corot]

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TODO: create noetic-devel branch and change the target for this PR
I will keep as draft meanwhile
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Without this PR, on noetic, unpacking any user data fails with

[/patrol_2_points_smach_viewer ERROR 1699086106.199530, 6.800000]: bad callback: <bound method SmachViewerFrame._status_msg_update of <__main__.SmachViewerFrame object at 0x7f0440864550>>
Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/rospy/topics.py", line 750, in _invoke_callback
    cb(msg)
  File "/home/jorge/catkin_ws/executive/src/executive_smach_visualization/smach_viewer/scripts/smach_viewer.py", line 530, in _status_msg_update
    SmachViewerBase._status_msg_update(self, msg)
  File "/home/jorge/catkin_ws/executive/src/executive_smach_visualization/smach_viewer/src/smach_viewer/smach_viewer_base.py", line 490, in _status_msg_update
    if container.update_status(msg):
  File "/home/jorge/catkin_ws/executive/src/executive_smach_visualization/smach_viewer/src/smach_viewer/smach_viewer_base.py", line 102, in update_status
    self._local_data._data = self._load_local_data(msg)
  File "/home/jorge/catkin_ws/executive/src/executive_smach_visualization/smach_viewer/src/smach_viewer/smach_viewer_base.py", line 75, in _load_local_data
    local_data = pickle.loads(
_pickle.UnpicklingError: pickle data was truncated

[k-okada]

@corot can you provide example code to reproduce this problem?
@tkmtnt7000 can you check if this patch works on your example #54 (comment) ?

[corot]

@corot can you provide example code to reproduce this problem?

To my understanding, this is a general problem in noetic. i.e. decoding any msg fails. Which makes sense because we encode using base64.

Can you visualize userdata on noetic w/o this fix?

[tkmtnt7000]

@tkmtnt7000 can you check if this patch works on your example #54 (comment) ?

Yes, but at this time it seems that this PR has not fixed the visualization failure yet.
And I did not encounter the error above with the sample code #54 (comment), so I would like to know how that error reproduces.

I got the following error with #54 code.

[ERROR] [1699329194.390787] [/smach_viewer]: [bad callback: <bound method SmachViewerFrame._status_msg_update of <__main__.SmachViewerFrame object at 0x7fcfd497d8b0>>
Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 75, in _load_local_data
    local_data = pickle.loads(msg.local_data)
TypeError: a bytes-like object is required, not 'str'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.8/base64.py", line 37, in _bytes_from_decode_data
    return s.encode('ascii')
UnicodeEncodeError: 'ascii' codec can't encode characters in position 27-32: ordinal not in range(128)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/rospy/topics.py", line 750, in _invoke_callback
    cb(msg)
  File "/opt/ros/noetic/lib/smach_viewer/smach_viewer.py", line 530, in _status_msg_update
    SmachViewerBase._status_msg_update(self, msg)
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 492, in _status_msg_update
    if container.update_status(msg):
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 104, in update_status
    self._local_data._data = self._load_local_data(msg)
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 78, in _load_local_data
    local_data = pickle.loads(base64.b64decode(msg.local_data))
  File "/usr/lib/python3.8/base64.py", line 80, in b64decode
    s = _bytes_from_decode_data(s)
  File "/usr/lib/python3.8/base64.py", line 39, in _bytes_from_decode_data
    raise ValueError('string argument should contain only ASCII characters')
ValueError: string argument should contain only ASCII characters
]
[ERROR] [1699329195.381758] [/smach_viewer]: [bad callback: <bound method SmachViewerFrame._status_msg_update of <__main__.SmachViewerFrame object at 0x7fcfd497d8b0>>
Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 75, in _load_local_data
    local_data = pickle.loads(msg.local_data)
TypeError: a bytes-like object is required, not 'str'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3.8/base64.py", line 37, in _bytes_from_decode_data
    return s.encode('ascii')
UnicodeEncodeError: 'ascii' codec can't encode characters in position 25-26: ordinal not in range(128)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/rospy/topics.py", line 750, in _invoke_callback
    cb(msg)
  File "/opt/ros/noetic/lib/smach_viewer/smach_viewer.py", line 530, in _status_msg_update
    SmachViewerBase._status_msg_update(self, msg)
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 492, in _status_msg_update
    if container.update_status(msg):
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 104, in update_status
    self._local_data._data = self._load_local_data(msg)
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 78, in _load_local_data
    local_data = pickle.loads(base64.b64decode(msg.local_data))
  File "/usr/lib/python3.8/base64.py", line 80, in b64decode
    s = _bytes_from_decode_data(s)
  File "/usr/lib/python3.8/base64.py", line 39, in _bytes_from_decode_data
    raise ValueError('string argument should contain only ASCII characters')
ValueError: string argument should contain only ASCII characters
]
[ERROR] [1699329196.382061] [/smach_viewer]: [bad callback: <bound method SmachViewerFrame._status_msg_update of <__main__.SmachViewerFrame object at 0x7fcfd497d8b0>>
Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 75, in _load_local_data
    local_data = pickle.loads(msg.local_data)
TypeError: a bytes-like object is required, not 'str'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/rospy/topics.py", line 750, in _invoke_callback
    cb(msg)
  File "/opt/ros/noetic/lib/smach_viewer/smach_viewer.py", line 530, in _status_msg_update
    SmachViewerBase._status_msg_update(self, msg)
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 492, in _status_msg_update
    if container.update_status(msg):
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 104, in update_status
    self._local_data._data = self._load_local_data(msg)
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 78, in _load_local_data
    local_data = pickle.loads(base64.b64decode(msg.local_data))
  File "/usr/lib/python3.8/base64.py", line 87, in b64decode
    return binascii.a2b_base64(s)
binascii.Error: Incorrect padding
]
[ERROR] [1699329197.381978] [/smach_viewer]: [bad callback: <bound method SmachViewerFrame._status_msg_update of <__main__.SmachViewerFrame object at 0x7fcfd497d8b0>>
Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 75, in _load_local_data
    local_data = pickle.loads(msg.local_data)
TypeError: a bytes-like object is required, not 'str'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/ros/noetic/lib/python3/dist-packages/rospy/topics.py", line 750, in _invoke_callback
    cb(msg)
  File "/opt/ros/noetic/lib/smach_viewer/smach_viewer.py", line 530, in _status_msg_update
    SmachViewerBase._status_msg_update(self, msg)
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 492, in _status_msg_update
    if container.update_status(msg):
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 104, in update_status
    self._local_data._data = self._load_local_data(msg)
  File "/opt/ros/noetic/lib/python3/dist-packages/smach_viewer/smach_viewer_base.py", line 78, in _load_local_data
    local_data = pickle.loads(base64.b64decode(msg.local_data))
  File "/usr/lib/python3.8/base64.py", line 87, in b64decode
    return binascii.a2b_base64(s)
binascii.Error: Incorrect padding