[sharosoo]

Fixes #238.

Changes

• Add Tasks.cancel_and_drain() in python/restate/server_context.py to cancel in-flight ctx.run tasks and await their unwinding (shielded against outer cancellation so child finally cleanup completes before propagating cancellation).
• Await self.tasks.cancel_and_drain() in ServerInvocationContext.create_poll_or_cancel_coroutine when DoProgressCancelSignalReceived is received before raising TerminalError('cancelled', 409).
• Add unit tests in tests/disconnect_hotloop.py verifying that in-flight ctx.run closures receive CancelledError and complete their finally cleanup before the handler catches TerminalError(409), including when the draining caller itself is cancelled.

[github-actions]

All contributors have signed the CLA ✍️ ✅
_{Posted by the CLA Assistant Lite bot.}

[sharosoo]

Closing this PR for now: draining in-flight ctx.run tasks unconditionally (and shielding the drain across repeated cancellations) conflicts with the intended cancellation semantics clarified in restatedev/restate#5591. Leaving #238 open to discuss whether an opt-in or bounded hook is appropriate.