Problematic to have to specify a scoping function?

[rsyring]

When using an app factory pattern, it's problematic to have to specify a scoping function prior to app init (which is where you can check app.testing):

from flask_webtest import get_scopefunc

db = SQLAlchemy(session_options={'scopefunc': get_scopefunc()})

def init_ext(app):
    db.init_app(app)

The default scoping function of flask-sqlalchemy is just using the app context:

def _app_ctx_id() -> int:
    """Get the id of the current Flask application context for the session scope."""
    return id(app_ctx._get_current_object())  # type: ignore[attr-defined]

This means that, instead of messing around with the scoping function, we can just push a new app context before the request and that will give us a different SA session. Presumably, this why @guruofgentoo added FLASK_WEBTEST_PUSH_APP_CONTEXT in 88d7251

As I think about all of this, it seems to me it would simplify our code base considerably if we:

• Push the app context by default, use the config option and/or TestApp(..., push_app_context=False) to change the default behavior.
• Get rid of all usage of and reference to SessionScope and greenlet
• Change docs to instruct pushing a new app context if/when a new session is needed.
  • I'm not sure how this applies to greenlets. Presumably there is some mechanism already in place that ensures the correct app context is in place when a greenlet comes back to code that is waiting? I.e. through the greenlet equivalent of a thread local?
  • Where did the greenlet need come from anyway? I saw the commit that added it but there was no commentary on why.
• If custom session logic is needed, there is nothing stopping someone from turning off the context push and setting up a scopfunc on their own.
• We could adjust the TestApp class to expose the context manager that is used to wrap each request thereby making it easy to subclass TestApp and wrap each request it makes in some custom functionality.

[guruofgentoo]

The commentary on greenlet is in the code. This was for backwards compatibility at the time, to support providing an ident method when flask no longer provided one.

FWIW, I believe my intent for FLASK_WEBTEST_PUSH_APP_CONTEXT was to set the precedent of config while leaving the default as the existing functionality (again, backwards compatibility), then circle back later to adjust the default behavior as a breaking change.

Agreed on all of the items listed above. If someone is locked into using an earlier version of flask for some reason, they'll be locked into using an earlier flask-webtest as well.