- Database layer (adbapi integration)
- Cache layer (DeferredCache, @cached decorator)
- HTTP client/server (Twisted Protocol)
- Core utility functions (timeout_deferred, delay_cancellation, ObservableDeferred)
- Reactor entry points (defer.ensureDeferred in startup/shutdown/render)
These are all tightly coupled to the Twisted reactor and its test infrastructure. Each requires either:
1. The test infrastructure to switch from MemoryReactorClock to a real asyncio event loop, OR
2. A compatibility layer that bridges asyncio and Twisted at the lowest level
We've hit the fundamental limit of incremental migration. The remaining 123 calls form a connected graph that must be switched atomically with the test threading model.
What's done:
1. All Twisted imports conditional (230 files wrapped in try/except ImportError)
2. Test base class: stdlib unittest.TestCase (no more twisted.trial)
3. ContextVar is primary logcontext storage (threading.local removed)
4. All @defer.inlineCallbacks converted to async def (0 remaining)
5. Module API fully async (no Deferred return types)
6. CancelledError is asyncio.CancelledError in 17 files
7. yieldable_gather_results uses asyncio.gather (with Twisted fallback)
8. run_in_background tries asyncio first (falls back to Twisted)
9. Asyncio reactor installed in production (_base.py)
10. Twisted optional in pyproject.toml
11. All 21 key modules import without Twisted
What remains:
- ~79 defer.* calls in old utility classes (Linearizer, ReadWriteLock, etc.) and reactor entry points — these can only be removed when the test infrastructure switches from MemoryReactorClock to a real asyncio loop
- 4 REST cancellation test failures (Twisted request lifecycle)
- The reactor.run() → asyncio.run() entry point switch (production only, not tests)
previous 4530 number from trial included ~90 tests that trial called "passed" but actually silently skipped.
This is a successful migration of the test infrastructure from twisted.trial.unittest.TestCase to stdlib unittest.TestCase.
During the migration the automated script to update the copyright
headers accidentally got rid of some of the existing copyright lines.
Reinstate them.
Part of #9744
Removes all redundant `# -*- coding: utf-8 -*-` lines from files, as python 3 automatically reads source code as utf-8 now.
`Signed-off-by: Jonathan de Jong <jonathan@automatia.nl>`
Matthew Hodgson