feat(TaskScheduler): introduce semaphore-based task scheduler (Epic 3, Story 3.1)

AGENTS.md

@@ -5,6 +5,18 @@ This file provides guidance to agents when working with code in this repository.
 - Settings View Pattern: When working on `SettingsView`, inputs must bind to the local `cachedState`, NOT the live `useExtensionState()`. The `cachedState` acts as a buffer for user edits, isolating them from the `ContextProxy` source-of-truth until the user explicitly clicks "Save". Wiring inputs directly to the live state causes race conditions.
 - Changesets: Do NOT create `.changeset` files for each commit or code change. Changesets are managed separately by maintainers and should not be generated by agents during normal development.
 
+## ESLint Suppressions
+
+`src/eslint-suppressions.json` tracks per-file counts of suppressed lint rules. Suppression counts must never increase. When touching a file, prefer reducing its count when the fix is local and low-risk; avoid broad unrelated cleanup.
+
+When writing new code:
+
+- Fix lint violations in the new code rather than suppressing them.
+- Avoid `as any`; use typed APIs directly (e.g. `RooCodeEventName.X` constants with typed `on()`/`listenerCount()`), or bracket notation (`obj["privateField"]`) to access private members. Prefer precise test doubles or `unknown` with a type guard over double assertions (`as unknown as T`); use double assertions only as a last resort, with a comment explaining why.
+- Avoid floating promises; add `void`, `await`, or `.catch()` as appropriate.
+- After editing a file, run `pnpm --dir src exec eslint --prune-suppressions --max-warnings=0 <relative-file>` and confirm the count for that file did not increase.
+- If a suppression is truly unavoidable (e.g. `vi.spyOn(Cls.prototype as any, "privateMethod")` where no typed alternative exists), document why in a comment next to the cast.
+
 ## Test Placement Guidance
 
 Prefer the narrowest test layer that proves the behavior. This follows standard test-pyramid guidance: keep most coverage in fast, focused tests; add integration tests for cross-module contracts; reserve end-to-end tests for full workflow confidence.

apps/vscode-e2e/src/fixtures/subtasks.ts

@@ -48,6 +48,15 @@ export const SUBTASK_XPROFILE_SAME_CHILD_RESULT = "Same-profile child completed"
 export const SUBTASK_XPROFILE_DIFFERENT_CHILD_RESULT = "Different-profile child completed"
 export const SUBTASK_XPROFILE_PARENT_RESULT = "Sequential cross-profile parent resumed"
 
+// Scheduler regression tests — exercises TaskScheduler + run() dispatch post-CodeRabbit fix.
+// Separate markers to avoid collisions with the other subtask fixtures.
+const SCHED_STANDALONE_MARKER = "SCHED_STANDALONE_INTERRUPT_RESUME"
+const SCHED_COMPLETED_MARKER = "SCHED_COMPLETED_REOPEN"
+export const SCHED_STANDALONE_PROMPT = `${SCHED_STANDALONE_MARKER}: Ask the user exactly this follow-up question: What is the square root of 64? After the user answers, complete with only the answer.`
+export const SCHED_STANDALONE_FOLLOWUP_ANSWER = "8"
+export const SCHED_COMPLETED_PROMPT = `${SCHED_COMPLETED_MARKER}: Complete immediately with the exact result "Scheduler completed task".`
+export const SCHED_COMPLETED_RESULT = "Scheduler completed task"
+
 const apiHangChildMatch = new RegExp(SUBTASK_API_HANG_CHILD_MARKER)
 
 const requestContains = (req: ChatCompletionRequest, expected: string[]) => {
@@ -396,6 +405,62 @@ export function addSubtaskFixtures(mock: InstanceType<typeof LLMock>) {
 		},
 	})
 
+	// Scheduler regression fixtures: standalone interrupted task resume and completed task reopen.
+	mock.addFixture({
+		match: {
+			predicate: (req: ChatCompletionRequest) =>
+				requestContains(req, [SCHED_STANDALONE_MARKER]) &&
+				!requestContains(req, ["call_sched_standalone_followup_001"]) &&
+				!requestContains(req, [`<user_message>\\n${SCHED_STANDALONE_FOLLOWUP_ANSWER}\\n</user_message>`]),
+		},
+		response: {
+			toolCalls: [
+				{
+					name: "ask_followup_question",
+					arguments: JSON.stringify({
+						question: "What is the square root of 64?",
+						follow_up: [{ text: SCHED_STANDALONE_FOLLOWUP_ANSWER }],
+					}),
+					id: "call_sched_standalone_followup_001",
+				},
+			],
+		},
+	})
+
+	mock.addFixture({
+		match: {
+			predicate: (req: ChatCompletionRequest) =>
+				toolResultContains(req, "call_sched_standalone_followup_001", [SCHED_STANDALONE_FOLLOWUP_ANSWER]) ||
+				requestContains(req, ["call_sched_standalone_followup_001", SCHED_STANDALONE_FOLLOWUP_ANSWER]) ||
+				requestContains(req, [
+					SCHED_STANDALONE_MARKER,
+					`<user_message>\\n${SCHED_STANDALONE_FOLLOWUP_ANSWER}\\n</user_message>`,
+				]),
+		},
+		response: {
+			toolCalls: [
+				{
+					name: "attempt_completion",
+					arguments: JSON.stringify({ result: SCHED_STANDALONE_FOLLOWUP_ANSWER }),
+					id: "call_sched_standalone_completion_002",
+				},
+			],
+		},
+	})
+
+	mock.addFixture({
+		match: { userMessage: new RegExp(SCHED_COMPLETED_MARKER) },
+		response: {
+			toolCalls: [
+				{
+					name: "attempt_completion",
+					arguments: JSON.stringify({ result: SCHED_COMPLETED_RESULT }),
+					id: "call_sched_completed_completion_001",
+				},
+			],
+		},
+	})
+
 	// Interrupted-child-resumes-and-reports-back scenario (#560)
 	mock.addFixture({
 		match: {

apps/vscode-e2e/src/suite/subtasks.test.ts

@@ -5,6 +5,10 @@ import { RooCodeEventName, type ClineMessage } from "@roo-code/types"
 import { setDefaultSuiteTimeout } from "./test-utils"
 import { sleep, waitFor, waitUntilCompleted } from "./utils"
 import {
+	SCHED_COMPLETED_PROMPT,
+	SCHED_COMPLETED_RESULT,
+	SCHED_STANDALONE_FOLLOWUP_ANSWER,
+	SCHED_STANDALONE_PROMPT,
 	SUBTASK_ABANDON_CHILD_FOLLOWUP_ANSWER,
 	SUBTASK_ABANDON_PARENT_PROMPT,
 	SUBTASK_API_HANG_CHILD_MARKER,
@@ -945,4 +949,139 @@ suite("Roo Code Subtasks", function () {
 			await waitFor(() => api.getCurrentTaskStack().length === 0).catch(() => {})
 		}
 	})
+
+	// TaskScheduler regression: resumeTask on a completed task must show resume_completed_task ask.
+	// Before the CodeRabbit fix, createTaskWithHistoryItem bypassed the scheduler and called
+	// Task.run() via the constructor's startTask: true default, causing run() to call startTask()
+	// (clearing history) instead of resumeTaskFromHistory().
+	test("resumeTask on a completed task presents resume_completed_task ask", async () => {
+		const api = globalThis.api
+		const asks: Record<string, ClineMessage[]> = {}
+		const says: Record<string, ClineMessage[]> = {}
+
+		const messageHandler = ({ taskId, message }: { taskId: string; message: ClineMessage }) => {
+			if (message.type === "ask") {
+				asks[taskId] = asks[taskId] || []
+				asks[taskId].push(message)
+			}
+			if (message.type === "say" && message.partial === false) {
+				says[taskId] = says[taskId] || []
+				says[taskId].push(message)
+			}
+		}
+
+		api.on(RooCodeEventName.Message, messageHandler)
+
+		try {
+			// Run a task to completion.
+			const taskId = await waitUntilCompleted({
+				api,
+				start: () =>
+					api.startNewTask({
+						configuration: {
+							mode: "ask",
+							autoApprovalEnabled: true,
+							enableCheckpoints: false,
+						},
+						text: SCHED_COMPLETED_PROMPT,
+					}),
+			})
+
+			assert.strictEqual(
+				says[taskId]?.find(({ say }) => say === "completion_result")?.text?.trim(),
+				SCHED_COMPLETED_RESULT,
+				"Task should complete with expected result",
+			)
+
+			// Re-open it via resumeTask — should hit resumeTaskFromHistory(), showing resume_completed_task.
+			await api.resumeTask(taskId)
+
+			await waitFor(
+				() => asks[taskId]?.some(({ type, ask }) => type === "ask" && ask === "resume_completed_task") ?? false,
+			)
+		} finally {
+			api.off(RooCodeEventName.Message, messageHandler)
+			while (api.getCurrentTaskStack().length > 0) {
+				await api.clearCurrentTask()
+			}
+			await sleep(500)
+		}
+	})
+
+	// TaskScheduler regression: resumeTask on an interrupted standalone task must show resume_task
+	// ask and allow the task to complete normally via the scheduler slot.
+	test("resumeTask on an interrupted standalone task presents resume_task ask and completes", async () => {
+		const api = globalThis.api
+		const asks: Record<string, ClineMessage[]> = {}
+		const says: Record<string, ClineMessage[]> = {}
+
+		const messageHandler = ({ taskId, message }: { taskId: string; message: ClineMessage }) => {
+			if (message.type === "ask") {
+				asks[taskId] = asks[taskId] || []
+				asks[taskId].push(message)
+			}
+			if (message.type === "say" && message.partial === false) {
+				says[taskId] = says[taskId] || []
+				says[taskId].push(message)
+			}
+		}
+
+		api.on(RooCodeEventName.Message, messageHandler)
+
+		let taskId: string | undefined
+
+		try {
+			taskId = await api.startNewTask({
+				configuration: {
+					mode: "ask",
+					autoApprovalEnabled: true,
+					enableCheckpoints: false,
+				},
+				text: SCHED_STANDALONE_PROMPT,
+			})
+
+			// Wait until the task pauses at the follow-up question.
+			await waitFor(() => asks[taskId!]?.some(({ type, ask }) => type === "ask" && ask === "followup") ?? false)
+
+			// Cancel it — the task becomes interrupted.
+			await api.cancelCurrentTask()
+
+			await waitFor(
+				() => asks[taskId!]?.some(({ type, ask }) => type === "ask" && ask === "resume_task") ?? false,
+			)
+
+			// Resume via scheduler path (createTaskWithHistoryItem).
+			const askCountBeforeResume = asks[taskId!]?.length ?? 0
+			await api.resumeTask(taskId!)
+
+			await waitFor(() =>
+				(asks[taskId!] ?? [])
+					.slice(askCountBeforeResume)
+					.some(({ type, ask }) => type === "ask" && ask === "resume_task"),
+			)
+
+			// Sending the answer both acknowledges the resume_task ask and answers the pending
+			// follow-up question from the original task, completing the task.
+			const completedTaskId = await waitUntilCompleted({
+				api,
+				start: async () => {
+					await api.sendMessage(SCHED_STANDALONE_FOLLOWUP_ANSWER)
+					return taskId!
+				},
+			})
+
+			assert.strictEqual(completedTaskId, taskId, "The resumed standalone task should complete")
+			assert.strictEqual(
+				says[taskId!]?.find(({ say }) => say === "completion_result")?.text?.trim(),
+				SCHED_STANDALONE_FOLLOWUP_ANSWER,
+				"Task should complete with the follow-up answer as result",
+			)
+		} finally {
+			api.off(RooCodeEventName.Message, messageHandler)
+			while (api.getCurrentTaskStack().length > 0) {
+				await api.clearCurrentTask()
+			}
+			await sleep(500)
+		}
+	})
 })