feat(tools): the guardedWrite tool on top of the writer's guard API (U5-A, #1375)

knip.json

@@ -16,7 +16,7 @@
 	"playwright-ct": false,
 	"workspaces": {
 		"src": {
-			"entry": ["extension.ts!", "extension/api.ts!", "workers/countTokens.ts!"],
+			"entry": ["extension.ts!", "extension/api.ts!", "workers/countTokens.ts!", "core/tools/guardedWrite.ts!"],
 			"project": [
 				"**/*.ts!",
 				"!**/__tests__/**!",

src/core/task/Task.ts

@@ -106,6 +106,7 @@ import { buildNativeToolsArrayWithRestrictions } from "./build-tools"
 import { ToolRepetitionDetector } from "../tools/ToolRepetitionDetector"
 import { restoreTodoListForTask } from "../tools/UpdateTodoListTool"
 import { FileContextTracker } from "../context-tracking/FileContextTracker"
+import { ObservationRegistry } from "./observationRegistry"
 import { RooIgnoreController } from "../ignore/RooIgnoreController"
 import { RooProtectedController } from "../protect/RooProtectedController"
 import { type AssistantMessageContent, presentAssistantMessage } from "../assistant-message"
@@ -296,6 +297,10 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 	readonly instanceId: string
 	readonly metadata: TaskMetadata
 
+	// The observed on-disk version of each file this task has read. Declared here so the
+	// read tools can record it; a write guard later compares a token against this registry.
+	readonly observationRegistry = new ObservationRegistry()
+
 	todoList?: TodoItem[]
 
 	readonly rootTask: Task | undefined = undefined
@@ -393,6 +398,11 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 	providerRef: WeakRef<ClineProvider>
 	private readonly globalStoragePath: string
 	abort: boolean = false
+	// Monotonic cancellation counter. `requestAbort()` and `requestDispose()` advance
+	// this fence, and the guarded-write path compares the value it captured when the
+	// write was queued with the value at publish time, so a queued write cannot publish
+	// after the task was cancelled or disposed.
+	cancellationGeneration: number = 0
 	currentRequestAbortController?: AbortController
 	/**
 	 * Controller for the waiter on an in-flight `ensureModelFetched()` call (see
@@ -3591,6 +3601,11 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 			this.abandoned = true
 		}
 		this.abort = true
+		// The S4a write guard compares this counter with the value a queued write
+		// captured when it started, so every cancellation must advance it; it must
+		// never go backwards because resumeAfterDelegation() clears `abort` (the
+		// flag alone cannot keep the cancelled run and the resumed run apart).
+		this.cancellationGeneration++
 		this.driveRunEvent({ tag: "abortRequested", abandoned: isAbandoned })
 	}
 
@@ -3601,6 +3616,10 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 
 	requestDispose(): void {
 		this.abort = true
+		// A host teardown never calls abortTask(): disposal has to raise the same
+		// counter, or a write still parked on its path chain publishes after the
+		// task is gone.
+		this.cancellationGeneration++
 		this.driveRunEvent({ tag: "disposeRequested" })
 	}
 
@@ -3629,6 +3648,7 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 
 	public abortTask(isAbandoned = false): Promise<void> {
 		this.requestAbort(isAbandoned)
+
 		this.cancelAssistantMessagePersistence()
 		this.abortPromise ??= this.abortTaskOnce()
 		return this.abortPromise
@@ -3751,6 +3771,13 @@ export class Task extends EventEmitter<TaskEvents> implements TaskLike {
 			console.error("Error removing event listeners:", error)
 		}
 
+		// A disposed task is no longer authoritative for what it read. The registry holds
+		// version tokens captured while the task was alive, and a disposed task can still be
+		// reachable through a parent/subtask reference; a guarded write must not accept one of
+		// those tokens for a file this task has not re-read since. Clearing also stops a long
+		// task from pinning every file it ever read.
+		this.observationRegistry.close()
+
 		// Release any terminals associated with this task.
 		try {
 			// Release any terminals associated with this task.

src/core/task/__tests__/Task.dispose.test.ts

@@ -3,6 +3,7 @@ import path from "node:path"
 import { type ProviderSettings, RooCodeEventName } from "@roo-code/types"
 
 import { Task } from "../Task"
+import { ObservationRegistry } from "../observationRegistry"
 import { ClineProvider } from "../../webview/ClineProvider"
 import { OutputInterceptor } from "../../../integrations/terminal/OutputInterceptor"
 import { providerIdentifiers } from "@roo-code/types/provider-identifiers"
@@ -118,6 +119,55 @@ describe("Task dispose method", () => {
 		expect(disposalComplete).toBe(true)
 	})
 
+	test("owns a per-Task observation registry", () => {
+		// ReadFileTool and the guarded-write path reach the registry only through the Task,
+		// so a Task that never built one - or shared one across Tasks - would silently drop
+		// read observations. The registry's own tests only exercise standalone instances, and
+		// the tool tests inject their own doubles, so nothing else pins this wiring.
+		expect(task.observationRegistry).toBeInstanceOf(ObservationRegistry)
+
+		const other = new Task({
+			provider: mockProvider as unknown as ClineProvider,
+			apiConfiguration: mockApiConfiguration,
+			startTask: false,
+		})
+		try {
+			expect(other.observationRegistry).toBeInstanceOf(ObservationRegistry)
+			expect(other.observationRegistry).not.toBe(task.observationRegistry)
+
+			// Observing in one Task must not be visible from another: parent and subtask
+			// authority over a file has to stay separate.
+			other.observationRegistry.observe("/workspace/a.ts", "v1", true)
+			expect(other.observationRegistry.get("/workspace/a.ts")?.version).toBe("v1")
+			expect(task.observationRegistry.has("/workspace/a.ts")).toBe(false)
+			expect(task.observationRegistry.size).toBe(0)
+		} finally {
+			void other.dispose().catch(() => {})
+		}
+	})
+
+	test("clears the per-Task observation registry on disposal", async () => {
+		// The registry holds on-disk version tokens for files this task read. Disposal does not
+		// free the Task object - a parent or subtask reference can outlive it - so a token
+		// captured before teardown must not survive as authority for a guarded write.
+		task.observationRegistry.observe("/workspace/a.ts", "v1", true)
+		task.observationRegistry.observe("/workspace/b.ts", "v2", false)
+		expect(task.observationRegistry.size).toBe(2)
+
+		await task.dispose()
+
+		expect(task.observationRegistry.size).toBe(0)
+		expect(task.observationRegistry.has("/workspace/a.ts")).toBe(false)
+		expect(task.observationRegistry.get("/workspace/b.ts")).toBeUndefined()
+
+		// A read that was still awaiting I/O when disposal began resumes afterwards. Its
+		// observation must not land in a retired registry, or the disposed Task would be
+		// authoritative for that file again.
+		expect(task.observationRegistry.closed).toBe(true)
+		task.observationRegistry.observe("/workspace/late.ts", "v3", true)
+		expect(task.observationRegistry.size).toBe(0)
+	})
+
 	test("should reject the memoized completion promise when disposal cannot start", async () => {
 		const disposalError = new Error("disposal failed")
 		skipCleanup = true

src/core/task/__tests__/Task.spec.ts

@@ -4768,6 +4768,56 @@ describe("Cline", () => {
 			).toHaveLength(1)
 		})
 
+		it("advances the cancellation generation on each cancellation and keeps it advanced across a resume", async () => {
+			// The S4a write guard compares the cancellation generation a queued write
+			// captured against the generation at publish time. The abort FLAG cannot do that
+			// on its own: resumeAfterDelegation() clears it, and a write that belongs to the
+			// cancelled run would then publish as if nothing had been cancelled. Only the
+			// generation keeps the two runs apart, so it must never go backwards.
+			const task = new Task({
+				provider: mockProvider,
+				apiConfiguration: mockApiConfig,
+				task: "test task",
+				startTask: false,
+			})
+			vi.spyOn(task, "dispose").mockResolvedValue(undefined)
+
+			expect(task.cancellationGeneration).toBe(0)
+
+			await task.abortTask()
+			expect(task.abort).toBe(true)
+			expect(task.cancellationGeneration).toBe(1)
+
+			await task.resumeAfterDelegation()
+			// The run-state model (RSK-06) no longer clears the legacy `abort` flag
+			// on resume: that is exactly why the generation exists. Only the
+			// generation keeps the cancelled run and the resumed run apart.
+			expect(task.cancellationGeneration).toBe(1)
+
+			await task.abortTask()
+			expect(task.abort).toBe(true)
+			expect(task.cancellationGeneration).toBe(2)
+		})
+
+		it("advances the cancellation generation on disposal, without any explicit cancel", async () => {
+			// A task torn down by the host never sees abortTask(). Disposal has to raise the
+			// same generation, or a write still parked on its path chain publishes after the
+			// task is gone.
+			const task = new Task({
+				provider: mockProvider,
+				apiConfiguration: mockApiConfig,
+				task: "test task",
+				startTask: false,
+			})
+
+			expect(task.cancellationGeneration).toBe(0)
+
+			await task.dispose()
+
+			expect(task.abort).toBe(true)
+			expect(task.cancellationGeneration).toBe(1)
+		})
+
 		it("flushes pending state before TaskAborted and disposal while queue state is intact", async () => {
 			const task = new Task({
 				provider: mockProvider,
@@ -7761,6 +7811,9 @@ describe("Cline", () => {
 			// task directory to exist (uuid v7 is mocked to the fixed id below).
 			const taskDir = path.join(os.tmpdir(), "test-storage", "tasks", "00000000-0000-7000-8000-000000000000")
 			fsReal.mkdirSync(taskDir, { recursive: true })
+			// Earlier tests in this file can leave a ui_messages.json for the fixed task id;
+			// merge=true would read it here and fail the first save stage for an unrelated reason.
+			fsReal.rmSync(path.join(taskDir, "ui_messages.json"), { force: true })
 			// Declared outside the try so the finally block can restore them.
 			const updateSpy = vi
 				.spyOn(getTaskTestAccess(Task.prototype), "updateClineMessage")

src/core/task/__tests__/observationRegistry.spec.ts

@@ -0,0 +1,132 @@
+import { describe, it, expect, vi } from "vitest"
+
+import { ObservationRegistry } from "../observationRegistry"
+
+describe("ObservationRegistry", () => {
+	it("observe → get returns the recorded version and observedAt", () => {
+		const reg = new ObservationRegistry()
+		reg.observe("/a/b/c.ts", "1:2:300:4000000000:5000000000")
+
+		const obs = reg.get("/a/b/c.ts")
+		expect(obs).toBeDefined()
+		expect(obs!.version).toBe("1:2:300:4000000000:5000000000")
+		expect(typeof obs!.observedAt).toBe("number")
+	})
+
+	it("re-observe replaces the entry with a fresh observedAt", () => {
+		vi.useFakeTimers()
+		const reg = new ObservationRegistry()
+		reg.observe("/a/b/c.ts", "v1")
+		const first = reg.get("/a/b/c.ts")!
+		expect(first.version).toBe("v1")
+
+		vi.advanceTimersByTime(50)
+		reg.observe("/a/b/c.ts", "v2")
+		const second = reg.get("/a/b/c.ts")!
+		expect(second.version).toBe("v2")
+		expect(second.observedAt).toBeGreaterThan(first.observedAt)
+
+		vi.useRealTimers()
+	})
+
+	it("has returns true for observed paths, false otherwise", () => {
+		const reg = new ObservationRegistry()
+		reg.observe("/x.ts", "t1")
+		expect(reg.has("/x.ts")).toBe(true)
+		expect(reg.has("/y.ts")).toBe(false)
+	})
+
+	it("size reflects the number of observed entries", () => {
+		const reg = new ObservationRegistry()
+		expect(reg.size).toBe(0)
+		reg.observe("/a.ts", "t1")
+		reg.observe("/b.ts", "t2")
+		expect(reg.size).toBe(2)
+	})
+
+	it("clear removes all entries and resets size to 0", () => {
+		const reg = new ObservationRegistry()
+		reg.observe("/a.ts", "t1")
+		reg.observe("/b.ts", "t2")
+		reg.clear()
+		expect(reg.size).toBe(0)
+		expect(reg.get("/a.ts")).toBeUndefined()
+		expect(reg.has("/b.ts")).toBe(false)
+	})
+
+	it("get on empty registry returns undefined", () => {
+		const reg = new ObservationRegistry()
+		expect(reg.get("/any.ts")).toBeUndefined()
+	})
+
+	it("separate instances are independent — observing in one does not appear in the other", () => {
+		const regA = new ObservationRegistry()
+		const regB = new ObservationRegistry()
+		regA.observe("/shared.ts", "v1")
+		expect(regA.get("/shared.ts")).toBeDefined()
+		expect(regB.get("/shared.ts")).toBeUndefined()
+		regB.observe("/shared.ts", "v2")
+		expect(regA.get("/shared.ts")!.version).toBe("v1")
+		expect(regB.get("/shared.ts")!.version).toBe("v2")
+	})
+
+	describe("completeness scope (S4b follow-up #46)", () => {
+		it("defaults to a complete observation when the read scope is not given", () => {
+			const reg = new ObservationRegistry()
+			reg.observe("/a/b/c.ts", "v1")
+
+			expect(reg.get("/a/b/c.ts")!.complete).toBe(true)
+		})
+
+		it("records a partial observation when the read only returned a view of the file", () => {
+			const reg = new ObservationRegistry()
+			reg.observe("/a/b/c.ts", "v1", false)
+
+			expect(reg.get("/a/b/c.ts")!.complete).toBe(false)
+		})
+
+		it("re-observing replaces the entry's completeness with the new read's scope", () => {
+			const reg = new ObservationRegistry()
+			reg.observe("/a/b/c.ts", "v1", false)
+			reg.observe("/a/b/c.ts", "v2")
+
+			const obs = reg.get("/a/b/c.ts")!
+			expect(obs.version).toBe("v2")
+			expect(obs.complete).toBe(true)
+		})
+
+		it("re-observing with a partial scope downgrades a previously complete entry", () => {
+			const reg = new ObservationRegistry()
+			reg.observe("/a/b/c.ts", "v1")
+			reg.observe("/a/b/c.ts", "v2", false)
+
+			const obs = reg.get("/a/b/c.ts")!
+			expect(obs.version).toBe("v2")
+			expect(obs.complete).toBe(false)
+		})
+	})
+
+	describe("closure on task disposal", () => {
+		it("close drops every entry and reports the registry closed", () => {
+			const reg = new ObservationRegistry()
+			reg.observe("/a/b/c.ts", "v1")
+			expect(reg.closed).toBe(false)
+
+			reg.close()
+
+			expect(reg.size).toBe(0)
+			expect(reg.get("/a/b/c.ts")).toBeUndefined()
+			expect(reg.closed).toBe(true)
+		})
+
+		it("observe is a no-op after close, so a read resuming after disposal records nothing", () => {
+			const reg = new ObservationRegistry()
+			reg.close()
+
+			reg.observe("/late.ts", "v1")
+
+			expect(reg.size).toBe(0)
+			expect(reg.has("/late.ts")).toBe(false)
+		})
+	})
+})