Flask v3.0.0 breaks `pytest-flask` import of `_request_ctx_stack`

[slint]

Describe the bug

Flask v3.0.0, released Sep 30th, removed _request_ctx_stack, used in fixtures.py

To Reproduce

1. Install pytest-flask
2. Run your tests
3. See import error

⚠️ Import error stacktrace ⚠️

Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/runpy.py", line 197, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/pytest/__main__.py", line 5, in <module>
    raise SystemExit(pytest.console_main())
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/_pytest/config/__init__.py", line 187, in console_main
    code = main()
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/_pytest/config/__init__.py", line 145, in main
    config = _prepareconfig(args, plugins)
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/_pytest/config/__init__.py", line 324, in _prepareconfig
    config = pluginmanager.hook.pytest_cmdline_parse(
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/pluggy/_hooks.py", line 493, in __call__
    return self._hookexec(self.name, self._hookimpls, kwargs, firstresult)
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/pluggy/_manager.py", line [11](https://github.com/zenodo/zenodo-rdm/actions/runs/6382674986/job/17321782664#step:8:12)5, in _hookexec
    return self._inner_hookexec(hook_name, methods, kwargs, firstresult)
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/pluggy/_callers.py", line 130, in _multicall
    teardown[0].send(outcome)
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/_pytest/helpconfig.py", line 102, in pytest_cmdline_parse
    config: Config = outcome.get_result()
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/pluggy/_result.py", line 114, in get_result
    raise exc.with_traceback(exc.__traceback__)
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/pluggy/_callers.py", line 77, in _multicall
    res = hook_impl.function(*args)
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/_pytest/config/__init__.py", line 1017, in pytest_cmdline_parse
    self.parse(args)
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/_pytest/config/__init__.py", line 1305, in parse
    self._preparse(args, addopts=addopts)
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/_pytest/config/__init__.py", line 1188, in _preparse
    self.pluginmanager.load_setuptools_entrypoints("pytest11")
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/pluggy/_manager.py", line 398, in load_setuptools_entrypoints
    plugin = ep.load()
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/importlib/metadata.py", line 86, in load
    module = import_module(match.group('module'))
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/importlib/__init__.py", line [12](https://github.com/zenodo/zenodo-rdm/actions/runs/6382674986/job/17321782664#step:8:13)7, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
  File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
  File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/_pytest/assertion/rewrite.py", line 168, in exec_module
    exec(co, module.__dict__)
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/pytest_invenio/plugin.py", line 25, in <module>
    from .fixtures import (
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/_pytest/assertion/rewrite.py", line 168, in exec_module
    exec(co, module.__dict__)
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/pytest_invenio/fixtures.py", line 22, in <module>
    from pytest_flask.plugin import _make_test_response_class
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/_pytest/assertion/rewrite.py", line 168, in exec_module
    exec(co, module.__dict__)
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/pytest_flask/plugin.py", line [14](https://github.com/zenodo/zenodo-rdm/actions/runs/6382674986/job/17321782664#step:8:15), in <module>
    from .fixtures import accept_any
  File "/opt/hostedtoolcache/Python/3.9.18/x64/lib/python3.9/site-packages/_pytest/assertion/rewrite.py", line [16](https://github.com/zenodo/zenodo-rdm/actions/runs/6382674986/job/17321782664#step:8:17)8, in exec_module
    exec(co, module.__dict__)
  File "/opt/hostedtoolcache/Python/3.9.[18](https://github.com/zenodo/zenodo-rdm/actions/runs/6382674986/job/17321782664#step:8:19)/x64/lib/python3.9/site-packages/pytest_flask/fixtures.py", line 6, in <module>
    from flask import _request_ctx_stack
ImportError: cannot import name '_request_ctx_stack' from 'flask' (/opt/hostedtoolcache/Python/3.9.18/x[64](https://github.com/zenodo/zenodo-rdm/actions/runs/6382674986/job/17321782664#step:8:65)/lib/python3.9/site-packages/flask/__init__.py)

Environment (please complete the following information):

• OS: any
• Python Version 3.9
• pytest-flask version 1.2.0

Additional context

It looks like there's a deprecation warning already for using the fixture, so a possible path for a fix would be to:

1. (Optional) "inline" the import inside the fixture function (to avoid affecting people still using the fixture with Flask <3.0.0, and give them a chance to respond to the deprecation warning).
2. Remove the fixture completely and release pytest-flask v2.0.0

[jonyscathe]

The request_ctx text fixture has had a deprecation warning on it for about two years.
Should that just be removed at which point request_ctx_stack is no longer needed?

[nicoddemus]

#168 is open to address this.