'ValueError: write to closed file' when using --output-document with redirects

[JustAnotherArchivist]

'ValueError: write to closed file' when using --output-document with redirects

[JustAnotherArchivist]

Also happens when downloading more than one URL, e.g. wpull --output-file foo URL0 URL1.

A very similar error happens on retries:

> wpull --output-document foo --tries 3 https://httpbingo.org/status/500
INFO Fetching ‘https://httpbingo.org/status/500’.

INFO Fetched ‘https://httpbingo.org/status/500’: 500 Internal Server Error. Length: 0 [unspecified].
.../lib/python3.6/site-packages/wpull/protocol/http/client.py:185: UserWarning: HTTP session did not complete.
  warnings.warn(_('HTTP session did not complete.'))
INFO Fetching ‘https://httpbingo.org/status/500’.

INFO Fetched ‘https://httpbingo.org/status/500’: 500 Internal Server Error. Length: 0 [unspecified].
ERROR Fatal exception.
Traceback (most recent call last):
  File ".../lib/python3.6/site-packages/wpull/application/app.py", line 157, in run
    yield from pipeline.process()
  File ".../lib/python3.6/site-packages/wpull/pipeline/pipeline.py", line 194, in process
    yield from self._process_one_worker()
  File ".../lib/python3.6/site-packages/wpull/pipeline/pipeline.py", line 215, in _process_one_worker
    task.result()
  File ".../lib/python3.6/site-packages/wpull/pipeline/pipeline.py", line 119, in process
    item = yield from self.process_one(_worker_id=worker_id)
  File ".../lib/python3.6/site-packages/wpull/pipeline/pipeline.py", line 103, in process_one
    yield from task.process(item)
  File ".../lib/python3.6/site-packages/wpull/application/tasks/download.py", line 492, in process
    yield from session.app_session.factory['Processor'].process(session)
  File ".../lib/python3.6/site-packages/wpull/processor/delegate.py", line 29, in process
    return (yield from processor.process(item_session))
  File ".../lib/python3.6/site-packages/wpull/processor/web.py", line 92, in process
    return (yield from session.process())
  File ".../lib/python3.6/site-packages/wpull/processor/web.py", line 186, in process
    yield from self._process_loop()
  File ".../lib/python3.6/site-packages/wpull/processor/web.py", line 245, in _process_loop
    exit_early, wait_time = yield from self._fetch_one(cast(Request, self._item_session.request))
  File ".../lib/python3.6/site-packages/wpull/processor/web.py", line 309, in _fetch_one
    action = self._handle_response(request, response)
  File ".../lib/python3.6/site-packages/wpull/processor/web.py", line 436, in _handle_response
    self._file_writer_session.discard_document(response)
  File ".../lib/python3.6/site-packages/wpull/writer.py", line 519, in discard_document
    response.body.flush()
  File ".../lib/python3.6/site-packages/wpull/writer.py", line 490, in flush
    self._stream.flush()
ValueError: flush of closed file
CRITICAL Sorry, Wpull unexpectedly crashed.
CRITICAL Please report this problem to the authors at Wpull's issue tracker so it may be fixed. If you know how to program, maybe help us fix it? Thank you for helping us help you help us all.
INFO Exiting with status 1.