"Server[1] disconnected unexpectedly" when inspecting python-pptx XML element in VS Code

Environment data

PTVSD version: old (4.x) or new (5.x) as bundled in VS Code 1.42.0/VS Code Python 2020.3.62694-dev
OS and version: Windows 10 1909
Python version (& distribution if applicable, e.g. Anaconda): Plain 3.8.1
Using VS Code or Visual Studio: VS Code

Actual behavior

I am not sure this is PTVSD's issue, or VSCode-Python's, or VS Code's, pyhton-pptx', or even Python's. But I have to start somewhere, and my naive assumption is that PTVSD should catch any crashed while inspecting variables.

Anyway, upon debugging below code, issuing "el" correctly yields

  el
> <Element {http://schemas.openxmlformats.org/presentationml/2006/main}ph at 0x223bd3a53b0>

in the Debug Console. Clicking > to expand the element leads to a crash (Method 1) or an infinitely rotating throbber (Method 2). This is the output for the crash:

: Server[1] disconnected unexpectedly
Traceback (most recent call last):
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_frame.py", line 712, in trace_dispatch
    self.do_wait_suspend(thread, frame, event, arg)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_frame.py", line 89, in do_wait_suspend
    self._args[0].do_wait_suspend(*args, **kwargs)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\pydevd.py", line 1772, in do_wait_suspend
    keep_suspended = self._do_wait_suspend(thread, frame, event, arg, suspend_type, from_this_thread, frames_tracker)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\pydevd.py", line 1803, in _do_wait_suspend
    self.process_internal_commands()
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\pydevd.py", line 1492, in process_internal_commands
    int_cmd.do_it(self)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_comm.py", line 549, in do_it
    self.method(dbg, *self.args, **self.kwargs)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_comm.py", line 722, in internal_get_variable_json
    for child_var in variable.get_children_variables(fmt=fmt):
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_suspended_frames.py", line 112, in get_children_variables
    lst = resolver.get_contents_debug_adapter_protocol(self.value, fmt=fmt)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_resolver.py", line 95, in get_contents_debug_adapter_protocol
    dct, used___dict__ = self._get_py_dictionary(obj)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_resolver.py", line 192, in _get_py_dictionary
    names, used___dict__ = self.get_names(var)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_resolver.py", line 174, in get_names
    if hasattr(var, '__dict__'):
TypeError: descriptor '__dict__' for '_OxmlElementBase' objects doesn't apply to a 'CT_Placeholder' object
Traceback (most recent call last):
  File "C:\Users\bers\AppData\Local\Programs\Python\Python38\lib\runpy.py", line 193, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "C:\Users\bers\AppData\Local\Programs\Python\Python38\lib\runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\__main__.py", line 45, in <module>
    cli.main()
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd/..\ptvsd\server\cli.py", line 361, in main
    run()
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd/..\ptvsd\server\cli.py", line 203, in run_file
    runpy.run_path(options.target, run_name="__main__")
  File "C:\Users\bers\AppData\Local\Programs\Python\Python38\lib\runpy.py", line 263, in run_path
    return _run_module_code(code, init_globals, run_name,
  File "C:\Users\bers\AppData\Local\Programs\Python\Python38\lib\runpy.py", line 96, in _run_module_code
    _run_code(code, mod_globals, init_globals,
  File "C:\Users\bers\AppData\Local\Programs\Python\Python38\lib\runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "c:\Work\bug.py", line 8, in <module>
    pass  # Method 1: set a manual breakpoint here; leads to crash
  File "c:\Work\bug.py", line 8, in <module>
    pass  # Method 1: set a manual breakpoint here; leads to crash
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_frame.py", line 712, in trace_dispatch
    self.do_wait_suspend(thread, frame, event, arg)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_frame.py", line 89, in do_wait_suspend
    self._args[0].do_wait_suspend(*args, **kwargs)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\pydevd.py", line 1772, in do_wait_suspend
    keep_suspended = self._do_wait_suspend(thread, frame, event, arg, suspend_type, from_this_thread, frames_tracker)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\pydevd.py", line 1803, in _do_wait_suspend
    self.process_internal_commands()
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\pydevd.py", line 1492, in process_internal_commands
    int_cmd.do_it(self)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_comm.py", line 549, in do_it
    self.method(dbg, *self.args, **self.kwargs)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_comm.py", line 722, in internal_get_variable_json
    for child_var in variable.get_children_variables(fmt=fmt):
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_suspended_frames.py", line 112, in get_children_variables
    lst = resolver.get_contents_debug_adapter_protocol(self.value, fmt=fmt)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_resolver.py", line 95, in get_contents_debug_adapter_protocol
    dct, used___dict__ = self._get_py_dictionary(obj)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_resolver.py", line 192, in _get_py_dictionary
    names, used___dict__ = self.get_names(var)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\new_ptvsd\no_wheels\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_resolver.py", line 174, in get_names
    if hasattr(var, '__dict__'):
TypeError: descriptor '__dict__' for '_OxmlElementBase' objects doesn't apply to a 'CT_Placeholder' object

Expected behavior

The element should be expanded as much as possible, catching exceptions along the way.

Steps to reproduce:

This is my launch configuration:

{
  "name": "Python: Current File",
  "type": "python",
  "request": "launch",
  "program": "${file}",
  "internalConsoleOptions": "openOnSessionStart",
  "console": "internalConsole",
  "justMyCode": false,
},

And this my code. Note there's two way to set a breakpoint, with different results. In both cases, upon hitting the breakpoint, issue el in the Debug Console, then click > to expand the result.

"""Setup: pip install python-pptx."""
import pptx

el = pptx.Presentation().slide_layouts[0].placeholders[0].placeholder_format._element

# breakpoint()  # Method 2: enable breakpoint() here; leads to infinite(?) throbber

pass  # Method 1: set a manual breakpoint here; leads to crash

# Repro bug by issuing "el" in Debug Console and expand the result

And here's the crash output with the old PTVSD:

: Canceled
Traceback (most recent call last):
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\ptvsd_launcher.py", line 48, in <module>
    main(ptvsdArgs)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\__main__.py", line 432, in main
    run()
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\__main__.py", line 316, in run_file
    runpy.run_path(target, run_name='__main__')
  File "C:\Users\bers\AppData\Local\Programs\Python\Python38\lib\runpy.py", line 263, in run_path
    return _run_module_code(code, init_globals, run_name,
  File "C:\Users\bers\AppData\Local\Programs\Python\Python38\lib\runpy.py", line 96, in _run_module_code
    _run_code(code, mod_globals, init_globals,
  File "C:\Users\bers\AppData\Local\Programs\Python\Python38\lib\runpy.py", line 86, in _run_code
    exec(code, run_globals)
  File "c:\Work\bug.py", line 8, in <module>
    pass  # Method 1: set a manual breakpoint here; leads to crash
  File "c:\Work\bug.py", line 8, in <module>
    pass  # Method 1: set a manual breakpoint here; leads to crash
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_frame.py", line 606, in trace_dispatch
    self.do_wait_suspend(thread, frame, event, arg)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_frame.py", line 97, in do_wait_suspend
    self._args[0].do_wait_suspend(*args, **kwargs)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\_vendored\pydevd\pydevd.py", line 1616, in do_wait_suspend
    keep_suspended = self._do_wait_suspend(thread, frame, event, arg, suspend_type, from_this_thread, frames_tracker)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\_vendored\pydevd\pydevd.py", line 1644, in _do_wait_suspend
    self.process_internal_commands()
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\_vendored\pydevd\pydevd.py", line 1350, in process_internal_commands
    int_cmd.do_it(self)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_comm.py", line 502, in do_it
    self.method(dbg, *self.args, **self.kwargs)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_comm.py", line 675, in internal_get_variable_json
    for child_var in variable.get_children_variables(fmt=fmt):
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_suspended_frames.py", line 111, in get_children_variables
    lst = resolver.get_contents_debug_adapter_protocol(self.value, fmt=fmt)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_resolver.py", line 95, in get_contents_debug_adapter_protocol
    dct, used___dict__ = self._get_py_dictionary(obj)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_resolver.py", line 192, in _get_py_dictionary
    names, used___dict__ = self.get_names(var)
  File "c:\Users\bers\.vscode\extensions\ms-python.python-2020.3.62694-dev\pythonFiles\lib\python\old_ptvsd\ptvsd\_vendored\pydevd\_pydevd_bundle\pydevd_resolver.py", line 174, in get_names
    if hasattr(var, '__dict__'):
TypeError: descriptor '__dict__' for '_OxmlElementBase' objects doesn't apply to a 'CT_Placeholder' object

microsoft / ptvsd