Creating file config skip filed issue

[upsonp]

I was creating a new sample configuration for a CHL file. I entered '18' in the header filed and got a 'something went wrong' message.

Stack trace:

Traceback (most recent call last):
  File "C:\Gov\Projects\djangoProject\dart\dart_env\lib\site-packages\asgiref\sync.py", line 534, in thread_handler
    raise exc_info[1]
  File "C:\Gov\Projects\djangoProject\dart\dart_env\lib\site-packages\django\core\handlers\exception.py", line 42, in inner
    response = await get_response(request)
  File "C:\Gov\Projects\djangoProject\dart\dart_env\lib\site-packages\django\core\handlers\base.py", line 253, in _get_response_async
    response = await wrapped_callback(
  File "C:\Gov\Projects\djangoProject\dart\dart_env\lib\site-packages\asgiref\sync.py", line 479, in __call__
    ret: _R = await loop.run_in_executor(
  File "C:\Program Files\Python310\lib\asyncio\futures.py", line 285, in __await__
    yield self  # This tells Task to wait for completion.
  File "C:\Program Files\Python310\lib\asyncio\tasks.py", line 304, in __wakeup
    future.result()
  File "C:\Program Files\Python310\lib\asyncio\futures.py", line 201, in result
    raise self._exception.with_traceback(self._exception_tb)
  File "C:\Gov\Projects\djangoProject\dart\dart_env\lib\site-packages\asgiref\current_thread_executor.py", line 40, in run
    result = self.fn(*self.args, **self.kwargs)
  File "C:\Gov\Projects\djangoProject\dart\dart_env\lib\site-packages\asgiref\sync.py", line 538, in thread_handler
    return func(*args, **kwargs)
  File "C:\Gov\Projects\djangoProject\dart\core\form_sample_type_config.py", line 379, in new_sample_config
    skip = int(request.POST['skip']) if 'skip' in request.POST else -1
ValueError: invalid literal for int() with base 10: ''

based on this, I think the issue is request.POST['skip'] had some value in it that couldn't be cast to an int.

[upsonp]

This can sort of be reproduced if the field is blank.

Click in the filed, press backspace or delete to clear the value, wait one second.

Add a check to make sure request.POST is not '' before trying to cast it

In fact, anywhere code looks like this:

            skip = int(request.POST['skip']) if 'skip' in request.POST else -1

should probably look like this:

           skip = int(request.POST.get('skip', -1) or -1)

if the post value is not set at all, -1 will be used as the default. If the post value is '', then it's interpreted as a NoneType and -1 is returned.