Since urllib3 v2 the re-export of connection.HTTPConnection in
urllib3.connectionpool was removed.
In this commit we use urllib3.connection where needed. Some references
to connectionpool.HTTPConnection are still there for backward
compatibility.
Closes#688
Introduce the `drop_unused_requests` option (False by default). If True, it will force the `Cassette` saving operation with only played old interactions and new ones if they exist. As a result, unused old requests are dropped.
Add `_old_interactions`, `_played_interactions` and `_new_interactions()`. The `_old_interactions` are previously recorded interactions loaded from Cassette files. The `_played_interactions` is a set of old interactions that were marked as played. A new interaction is a tuple (request, response) in `self.data` that is not in `_old_interactions` list.
The initial technique to implement `record_on_exception=False` was to
not emptying the generator returned by
`CassetteContextDecorator._patch_generator` when an exception happens to
skip the `cassette._save` call, however this had the side effect of not
emptying the `ExitStack` created inside the generator which contains the
`_patch.__exit__` calls to remove the patches.
This was innocuous in CPython, which uses a reference counting garbage
collector so the `ExitStack` was immediately collected after losing
scope and therefore its `__exit__` method executed.
Pypy, on the other hand, uses a generational garbage collector so its
objects may survive more time, enough for the `ExitStack` not called
until much later, which may cause the patches to live more than expected
when `record_on_exception=False`.
This was found because the test
`test_nesting_context_managers_by_checking_references_of_http_connection`
was failing because it was executed after
`test_dont_record_on_exception`.
Now the cassette instance is saved inside the `CassetteContextDecorator`
instance to have better control on where to save the cassette, and moved
the `cassette._save` call from the `_patch_generator` method to the
`__exit__` method to be free to empty the generator and remove the
patches always.
