feat(generation): support user cancellation of a running session#48
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akozak-gd wants to merge 4 commits into
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feat(generation): support user cancellation of a running session#48akozak-gd wants to merge 4 commits into
akozak-gd wants to merge 4 commits into
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Cancelling a generation previously just called fail_generation_session, which sent an "❌ Run Failed" notification, marked the session FAILED (indistinguishable from a real failure), and never stopped the running workflow task or its agent subprocesses. Introduce a distinct terminal CANCELLED status and make cancellation actually stop in-flight work through two mechanisms: - A process-local generation_id → asyncio.Task registry so the owning pod calls task.cancel() for immediate teardown. The task registers itself via asyncio.current_task(), so no plumbing is needed at the create_task sites (initial run, retry, and boot recovery). - Cooperative raise_if_cancelled() checks (throttled DB reads) in the orchestrator step loop, execute_all_phases, the parallel executors, and the P10Y poll loop, raising GenerationCancelledError as a cross-pod-safe fallback. The cancel endpoint sets CANCELLED first, then cancels the task, so the injected CancelledError and any GenerationCancelledError unwind against an already-terminal state and neither re-fails nor notifies. The state machine cancel() mirrors interrupted_by_shutdown(): notification-free, sets cancelled_by_user/cancelled_at markers, ends the API-key slot, and retains workspaces (Commandment II) — generated code is preserved and reclaimed by scheduled_wipe. agent_query now aclose()s the SDK query stream so the Claude Code CLI subprocess is torn down on cancel. A CANCELLED session is terminal: boot recovery and the stuck detectors already exclude it, and retry now refuses it with a clear message.
raise_if_cancelled used 0.0 as the "never checked" throttle sentinel. time.monotonic() has no fixed epoch, so on a freshly-booted host (e.g. a CI runner) the clock can be smaller than min_interval_s, making now - 0.0 < min_interval_s true and throttling the very first read. Use a None sentinel so the first check for a generation always reads.
Replace the module-level global dict + functions with a GenerationTaskRegistry class. One instance is created at app startup and stored on app.state; the run/retry/cancel endpoints receive it via a get_generation_task_registry dependency, and it is threaded into the workflow task bodies (and boot recovery) as a parameter. This removes mutable import-time global state, aligns with the codebase's dependency-injection and OOP conventions, and lets tests inject the registry via dependency_overrides instead of reaching into module internals. Behavior is unchanged: same process-local fast cancel backed by the cooperative status check.
Wire the backend cancellation (PR #48) into the Textual TUI. Detail screen (DashboardScreen): add an `x` → cancel binding, shown only while the run is active (check_action gates it to pending/initializing/ running). Confirming pops a ConfirmScreen, then calls the existing DELETE /api/v1/generation-sessions/{id} for that specific session and refreshes in place — no terminal suspend, since cancellation is silent. Sessions list: a cancelled row now renders "⊘ CANCELLED BY USER". Recognize the status everywhere it matters: add a CANCELLED pill and put "cancelled" in TERMINAL_STATUSES (so the dashboard stops polling and the header pill renders), keep the cli_service mirror in sync, announce a cancel as a neutral "Generation cancelled" desktop milestone instead of a failure, and add CANCELLED to the mcp_server GenerationStatus mirror for client/backend parity.
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Summary
Adds user-initiated cancellation of a running generation across the whole stack. Cancelling stops all in-flight agents immediately, moves the session to a distinct terminal CANCELLED state that is never resumed on restart or retried, sends no error notification, and is exposed in the TUI on both the generation-detail and sessions-list screens.
Entrypoint
Backend:
cancel_generation_session(theDELETE /{generation_id}route) inbackend/app/api/v1/generation_sessions.py. TUI: the newx→ cancel binding and_cancel_flowonDashboardScreeninmcp_server/tui/app.py.Details
Cancellation uses two stop mechanisms: a process-local generation-id→
asyncio.Taskregistry (an injectedGenerationTaskRegistrycreated at app startup and threaded through the run/retry/cancel endpoints and boot recovery) for immediatetask.cancel()on the owning pod, plus a throttled cooperativeraise_if_cancelledcheck wired into the workflow, phase, parallel, and P10Y loops as a cross-pod-safe fallback that always runs on its first call for a generation. The endpoint setsCANCELLEDbefore cancelling the task so the injectedCancelledErrorandGenerationCancelledErrorunwind against an already-terminal state and never re-fail or notify; the state-machinecancel()mirrorsinterrupted_by_shutdown()and retains workspaces per Steel Commandment II, andagent_querynowaclose()s the SDK stream so the Claude Code CLI subprocess is torn down deterministically. The TUI recognizescancelledeverywhere it matters — a⊘ CANCELLEDpill,cancelledadded toTERMINAL_STATUSESso the dashboard stops polling, a "CANCELLED BY USER" label in the sessions list, and a neutral "Generation cancelled" desktop milestone instead of a failure. Boot recovery and the stuck detectors already excludeCANCELLED, and retry refuses it with a clear message.