- This commit replaces session modification trackers with event-based
session invalidation. The removal of modification trackers should
improve overall performance, because session invalidation events
happen less frequently than sessions are accessed. Getting rid of
modification trackers also allows sessions to refer to other sessions
lazily, which is essential when cyclic dependencies occur.
- The new `LLFirSession` validity tracker has constant complexity and
will not cause the same kind of performance issues as dependency
modification trackers. It is a bridge to support modification trackers
in certain parts of the code (e.g. for `CachedValue`s), while being
backed by event-based invalidation.
- `LLFirSessionInvalidationService` is the bridge between modification
events and `LLFirSessionCache`. It finds out which modules should be
invalidated and instructs the session cache to remove the associated
sessions.
- Session invalidation must always happen in a write action to preserve
consistency between sessions. Otherwise, while a session A is already
removed from the cache, it might still be referenced by a dependent
session B which is in the process of being invalidated. Such a session
must never be returned from `getSession`.
^KT-57515 fixed
Marco Pennekamp
e76692ef8d