Commit on teardown

[mgax]

A common pattern is to automatically commit the database session when a request is handled, provided no exception was raised.

[mitsuhiko]

I like this.

[stevesw]

Is it really safe to call session.commit() from @app.teardown_appcontext? What happens when session.commit() throws an exception?

[Turbo87]

@mgax it seems that this does not work when the debugger is used. when the exception is handled by the debugger the teardown function won't get called at all and on the next request the function is called without an exception which commits the changes.

[mgax]

@Turbo87, you're right, the session is not getting cleaned up. Looks like this happened before the patch too, but it only caused problems if the first reqest after the error did an explicit commit.

[mgax]

Digging around some more. The first request after the error pushes a new context, which causes the error's context to be popped, teardown_appcontext is called with no exception, and the autocommit function erroneously believes it's safe to commit.

Which, of course, is what you said, but I failed to parse. :)