Sphinx-doc conflicts with Pony

[ichorid]

Importing Pony's OperationalError causes sphinx-doc to fail:

+ cd tribler/doc
+ sphinx-build . _build/html -W -v
Running Sphinx v2.3.1

Traceback (most recent call last):
  File "/usr/local/lib/python3.7/dist-packages/sphinx/config.py", line 368, in eval_config_file
    execfile_(filename, namespace)
  File "/usr/local/lib/python3.7/dist-packages/sphinx/util/pycompat.py", line 81, in execfile_
    exec(code, _globals)
  File "/home/jenkins/ci/workspace/GH_Tribler_PR_Tests/PR_build_docs/tribler/doc/conf.py", line 63, in <module>
    from tribler_core.restapi.root_endpoint import RootEndpoint
  File "/home/jenkins/ci/workspace/GH_Tribler_PR_Tests/PR_build_docs/tribler/src/tribler-core/tribler_core/restapi/root_endpoint.py", line 8, in <module>
    from tribler_core.modules.metadata_store.restapi.channels_endpoint import ChannelsEndpoint
  File "/home/jenkins/ci/workspace/GH_Tribler_PR_Tests/PR_build_docs/tribler/src/tribler-core/tribler_core/modules/metadata_store/restapi/channels_endpoint.py", line 20, in <module>
    from tribler_core.modules.metadata_store.community.gigachannel_community import NoChannelSourcesException
  File "/home/jenkins/ci/workspace/GH_Tribler_PR_Tests/PR_build_docs/tribler/src/tribler-core/tribler_core/modules/metadata_store/community/gigachannel_community.py", line 15, in <module>
    from tribler_core.modules.metadata_store.community.remote_query_community import (
  File "/home/jenkins/ci/workspace/GH_Tribler_PR_Tests/PR_build_docs/tribler/src/tribler-core/tribler_core/modules/metadata_store/community/remote_query_community.py", line 12, in <module>
    from pony.orm.dbapiprovider import OperationalError
  File "<frozen importlib._bootstrap>", line 983, in _find_and_load
  File "<frozen importlib._bootstrap>", line 963, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 906, in _find_spec
  File "<frozen importlib._bootstrap_external>", line 1280, in find_spec
  File "<frozen importlib._bootstrap_external>", line 1246, in _get_spec
TypeError: 'Mock' object is not iterable

[devos50]

We are mocking the imports to be able to extract the API documentation, see here. You most likely have to add pony.orm.dbapiprovider to this list 👍

[xoriole]

Currently, build is success for sphinx version: 2.3.1 so the original issue is fixed. However, sphinx-build is failing for the latest version: 4.1.0

Traceback (most recent call last):
  File "/home/sysadmin/tudelft/tribler/venv/lib/python3.8/site-packages/sphinx/cmd/build.py", line 280, in build_main
    app.build(args.force_all, filenames)
  File "/home/sysadmin/tudelft/tribler/venv/lib/python3.8/site-packages/sphinx/application.py", line 343, in build
    self.builder.build_update()
  File "/home/sysadmin/tudelft/tribler/venv/lib/python3.8/site-packages/sphinx/builders/__init__.py", line 293, in build_update
    self.build(to_build,
  File "/home/sysadmin/tudelft/tribler/venv/lib/python3.8/site-packages/sphinx/builders/__init__.py", line 307, in build
    updated_docnames = set(self.read())
  File "/usr/lib/python3.8/contextlib.py", line 120, in __exit__
    next(self.gen)
  File "/home/sysadmin/tudelft/tribler/venv/lib/python3.8/site-packages/sphinx/util/logging.py", line 213, in pending_warnings
    memhandler.flushTo(logger)
  File "/home/sysadmin/tudelft/tribler/venv/lib/python3.8/site-packages/sphinx/util/logging.py", line 178, in flushTo
    logger.handle(record)
  File "/usr/lib/python3.8/logging/__init__.py", line 1599, in handle
    self.callHandlers(record)
  File "/usr/lib/python3.8/logging/__init__.py", line 1661, in callHandlers
    hdlr.handle(record)
  File "/usr/lib/python3.8/logging/__init__.py", line 950, in handle
    rv = self.filter(record)
  File "/usr/lib/python3.8/logging/__init__.py", line 811, in filter
    result = f.filter(record)
  File "/home/sysadmin/tudelft/tribler/venv/lib/python3.8/site-packages/sphinx/util/logging.py", line 423, in filter
    raise exc
sphinx.errors.SphinxWarning: <openapi>:1:Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.

Warning, treated as error:
<openapi>:1:Problem in http domain: field is supposed to use role 'obj', but that role is not in the domain.

[xoriole]

Documentation build is fixed with this PR: #6329