Unclosed <match> tag breaks search

[bbonf]

From the logs:

Traceback (most recent call last):
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/env/lib64/python3.8/site-packages/django/core/handlers/exception.py", line 55, in inner
    response = get_response(request)
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/env/lib64/python3.8/site-packages/django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/env/lib64/python3.8/site-packages/django/views/decorators/csrf.py", line 56, in wrapper_view
    return view_func(*args, **kwargs)
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/env/lib64/python3.8/site-packages/django/views/generic/base.py", line 104, in view
    return self.dispatch(request, *args, **kwargs)
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/env/lib64/python3.8/site-packages/rest_framework/views.py", line 509, in dispatch
    response = self.handle_exception(exc)
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/env/lib64/python3.8/site-packages/rest_framework/views.py", line 469, in handle_exception
    self.raise_uncaught_exception(exc)
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/env/lib64/python3.8/site-packages/rest_framework/views.py", line 480, in raise_uncaught_exception
    raise exc
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/env/lib64/python3.8/site-packages/rest_framework/views.py", line 506, in dispatch
    response = handler(request, *args, **kwargs)
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/env/lib64/python3.8/site-packages/rest_framework/decorators.py", line 50, in handler
    return func(*args, **kwargs)
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/source/backend/search/views.py", line 214, in search_view
    results, percentage, counts = query.get_results(maximum_results, exclude=returned)
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/source/backend/search/models.py", line 343, in get_results
    matches = result_obj.get_results()
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/source/backend/search/models.py", line 90, in get_results
    return parse_search_result(results, self.component.slug)
  File "/hum/web/gw-c-dh-gretel5.im.hum.uu.nl/data/source/backend/search/basex_search.py", line 204, in parse_search_result
    raise ValueError('Cannot parse XQuery result: <match> '
ValueError: Cannot parse XQuery result: <match> is not closed in 

Maybe it happens when the results are still being written? In any case, a single error like this causes /search to return 500 and break the entire results page for the user, which isn't ideal