Fix the remaining latent bugs found by the type checker

[wbarnha]

Six bugs across five modules, all surfaced by the type checker in #758 and left marked XXX there because fixing them changes runtime behaviour. One commit per bug, each with a regression test.

#758 has since been squash-merged, so this branch has been rebased onto master and now contains only the six fixes. Independent of #759, which fixes the two aiokafka crashes — they touch disjoint files and can merge in either order.

What was broken

Module	Bug
auth.py	SSLCredentials() raised TypeError — could not build a context at all
__init__.py	faust.version_info.major was 'v'; every field was wrong
tables/base.py	on_window_close never received the aggregated window data
tables/recovery.py	changelog events applied to an unrelated table; aborted-tx fixup silently skipped
cli/base.py	require_app = False commands crashed — faust completion unusable without -A
transport/drivers/confluent.py	key_partition dead on arrival; livelock detector raised every tick

SSLCredentials could not be constructed

purpose defaulted to None and went straight into ssl.create_default_context(purpose=...), which starts if not isinstance(purpose, _ASN1Object): raise TypeError(purpose). Any call that did not pass an explicit context raised — which defeats the cafile/capath/cadata parameters entirely. Now defaults to ssl.Purpose.SERVER_AUTH, the same default create_default_context() itself uses and the right one for a client verifying a broker; the tests assert the resulting context has check_hostname=True and verify_mode=CERT_REQUIRED.

faust.version_info held strings in its int fields

The regex groups (prefix, version, suffix) were splatted positionally into VersionInfo(major, minor, micro, ...), giving VersionInfo(major=None, minor='0.11.5', micro=''). Now parsed properly, with any non-numeric tail (dev1+g1234, rc1) going to releaselevel. An unparsable version degrades to VersionInfo(0, 0, 0, ...) instead of raising, so import faust can no longer fail on it.

This changes a public value. Code reading faust.version_info.minor as the version string must use faust.__version__, which is unchanged. Nothing in the repo consumes it and no docs reference it.

on_window_close never got its window data

_del_old_keys read _partition_timestamp_keys with the whole (start, end) tuple as the second key element; the map is keyed on range_end alone, written that way by _maybe_set_key_ttl and read that way by _maybe_del_key_ttl. The lookup could never hit, so triggered_windows was always [None, ...] and on_window_close only ever saw the raw per-key value.

User-visible: applications with an on_window_close handler will start receiving the aggregated data the API always promised.

Recovery applied events to whichever table came last

_slurp_changelogs binds table/offsets/bufsize per TP. The else: branch for an untracked TP only logged a warning and fell through, so the event was applied using the previous iteration's bindings — or raised UnboundLocalError if it was the first event. Now skipped. Worth noting a bare continue would be wrong: _maybe_signal_recovery_end() and the standby bookkeeping at the bottom of the loop must still run every iteration, so only the application block is skipped.

Separately, detect_aborted_tx compared await consumer.position(tp) >= highwater unguarded. position is Optional[int] and does return None, raising TypeError — swallowed by the caller's except Exception, which then skipped the aborted-transaction fixup for every remaining partition.

require_app = False was unusable

_app_from_str returns None for such a command invoked without -A, then AppCommand.__init__ did key_serializer or self.app.conf.key_serializer unconditionally. self.app is now a property over an Optional[AppT], with on_stop and blocking_timeout no longer assuming an app. Behaviour with an app present is unchanged, and require_app = True still raises the same UsageError.

confluent driver

key_partition reached for list_topics on ProducerThread.producer — the Faust producer — rather than ._producer, the confluent handle. And Consumer.verify_event_path delegated to a method no thread class defines, so the livelock detector raised every tick; it now has the same documented no-op the base Consumer.verify_event_path already is. A real livelock implementation is separate work.

Verification

mypy -p faust clean, scripts/check clean, suites 2207 → 2234 passed, 4 skipped.

Every new test was checked against the pre-fix code by overlaying the test files onto a pristine tree built from git archive. All fail there except the two noted below.

Two honest caveats:

• The confluent fixes are unverified by execution. tests/unit/transport/drivers/test_confluent.py opens with pytest.importorskip("confluent_kafka"), and confluent-kafka is the optional faust[ckafka] extra that the CI test environment does not install. The tests are written and will run where the extra is present; here they are skipped. Those two fixes rest on reading the class definitions.
• tests/unit/cli/test_base.py::test_init__serializers_without_app passes against pre-fix code too — both serializers it passes are truthy, so the old code short-circuits before dereferencing the None app. It documents the case but is not a guard; test_init__no_app_when_not_required is the one that actually fails pre-fix.

No existing test was weakened or deleted. The only removed test lines are an unused import, three mock_ranges calls replaced with explicit (start, end) tuples (the mock returned bare floats, which is not what _window_ranges yields), and two mock-setup lines that pointed at the very attribute the confluent fix corrects.

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