Revert "Support timing out hung streams (#308517)"

extensions/copilot/src/platform/endpoint/node/messagesApi.ts

@@ -5,7 +5,7 @@
 
 import { ContentBlockParam, DocumentBlockParam, ImageBlockParam, MessageParam, RedactedThinkingBlockParam, TextBlockParam, ThinkingBlockParam, ToolReferenceBlockParam, ToolResultBlockParam } from '@anthropic-ai/sdk/resources';
 import { Raw } from '@vscode/prompt-tsx';
-import { Response, withStreamIdleTimeout } from '../../../platform/networking/common/fetcherService';
+import { Response } from '../../../platform/networking/common/fetcherService';
 import { AsyncIterableObject } from '../../../util/vs/base/common/async';
 import { SSEParser } from '../../../util/vs/base/common/sseParser';
 import { generateUuid } from '../../../util/vs/base/common/uuid';
@@ -593,7 +593,7 @@ export async function processResponseFromMessagesEndpoint(
 			}
 		});
 
-		for await (const chunk of withStreamIdleTimeout(response.body)) {
+		for await (const chunk of response.body) {
 			parser.feed(chunk);
 		}
 	}, async () => {

extensions/copilot/src/platform/endpoint/node/responsesApi.ts

@@ -5,7 +5,7 @@
 
 import { Raw } from '@vscode/prompt-tsx';
 import type { OpenAI } from 'openai';
-import { Response, withStreamIdleTimeout } from '../../../platform/networking/common/fetcherService';
+import { Response } from '../../../platform/networking/common/fetcherService';
 import { coalesce } from '../../../util/vs/base/common/arrays';
 import { AsyncIterableObject } from '../../../util/vs/base/common/async';
 import { binaryIndexOf } from '../../../util/vs/base/common/buffer';
@@ -534,7 +534,7 @@ export async function processResponseFromChatEndpoint(instantiationService: IIns
 			}
 		});
 
-		for await (const chunk of withStreamIdleTimeout(response.body)) {
+		for await (const chunk of response.body) {
 			parser.feed(chunk);
 		}
 	}, async () => {

extensions/copilot/src/platform/networking/common/fetcherService.ts

@@ -296,84 +296,6 @@ export class DestroyableStream<T> implements AsyncIterable<T> {
 	}
 }
 
-/**
- * How long to wait (ms) for the first SSE chunk. The model's TTFT is often longer
- * than the subsequent chunks so we give it slightly more time.
- */
-export const SSE_FIRST_CHUNK_TIMEOUT_MS = 2 * 60 * 1000;
-
-/**
- * How long to wait (ms) between subsequent SSE chunks once streaming has
- * started. Once the model is actively streaming, gaps this long indicate
- * a hung connection.
- */
-export const SSE_IDLE_TIMEOUT_MS = 60 * 1000;
-
-export class StreamIdleTimeoutError extends Error {
-	constructor(timeoutMs: number, isFirstChunk: boolean) {
-		super(isFirstChunk
-			? `SSE stream timed out waiting ${timeoutMs}ms for the first chunk`
-			: `SSE stream timed out after ${timeoutMs}ms of inactivity`);
-		this.name = 'StreamIdleTimeoutError';
-	}
-}
-
-/**
- * Wraps a {@link DestroyableStream} with an idle watchdog. Uses a longer
- * timeout ({@link SSE_FIRST_CHUNK_TIMEOUT_MS}) while waiting for the first
- * chunk, then switches to {@link SSE_IDLE_TIMEOUT_MS} for subsequent chunks.
- * If no chunk arrives within the active timeout, the stream is destroyed
- * and a {@link StreamIdleTimeoutError} is thrown.
- */
-export async function* withStreamIdleTimeout<T>(
-	stream: DestroyableStream<T>,
-): AsyncGenerator<T> {
-	let timedOut = false;
-	let isFirstChunk = true;
-	let timer: ReturnType<typeof setTimeout> | undefined;
-
-	const clearTimer = () => {
-		if (timer !== undefined) {
-			clearTimeout(timer);
-			timer = undefined;
-		}
-	};
-
-	const startTimer = (timeoutMs: number) => {
-		clearTimer();
-		timer = setTimeout(() => {
-			timedOut = true;
-			void stream.destroy().catch(() => { });
-		}, timeoutMs);
-	};
-
-	const iterator = stream[Symbol.asyncIterator]();
-	try {
-		while (true) {
-			// Timer runs only while awaiting the next chunk from the network
-			startTimer(isFirstChunk ? SSE_FIRST_CHUNK_TIMEOUT_MS : SSE_IDLE_TIMEOUT_MS);
-			const result = await iterator.next();
-			clearTimer();
-
-			if (result.done) {
-				break;
-			}
-
-			isFirstChunk = false;
-			// Consumer processing time is NOT timed — the timer is cleared above
-			yield result.value;
-		}
-	} finally {
-		clearTimer();
-		await iterator.return?.();
-	}
-
-	if (timedOut) {
-		const timeoutMs = isFirstChunk ? SSE_FIRST_CHUNK_TIMEOUT_MS : SSE_IDLE_TIMEOUT_MS;
-		throw new StreamIdleTimeoutError(timeoutMs, isFirstChunk);
-	}
-}
-
 export async function jsonVerboseError(resp: Response) {
 	const text = await resp.text();
 	try {

extensions/copilot/src/platform/networking/node/stream.ts

@@ -10,7 +10,7 @@ import { TelemetryData } from '../../telemetry/common/telemetryData';
 import { RawThinkingDelta, ThinkingDelta } from '../../thinking/common/thinking';
 import { extractThinkingDeltaFromChoice, } from '../../thinking/common/thinkingUtils';
 import { FinishedCallback, getRequestId, ICodeVulnerabilityAnnotation, ICopilotBeginToolCall, ICopilotConfirmation, ICopilotError, ICopilotFunctionCall, ICopilotReference, ICopilotToolCall, ICopilotToolCallStreamUpdate, IIPCodeCitation, isCodeCitationAnnotation, isCopilotAnnotation, RequestId } from '../common/fetch';
-import { DestroyableStream, Response, withStreamIdleTimeout } from '../common/fetcherService';
+import { DestroyableStream, Response } from '../common/fetcherService';
 import { APIErrorResponse, APIJsonData, APIUsage, ChoiceLogProbs, FilterReason, FinishedCompletionReason, isApiUsage, IToolCall } from '../common/openai';
 
 /** Gathers together many chunks of a single completion choice. */
@@ -320,7 +320,7 @@ export class SSEProcessor {
 		let thinkingFound = false;
 
 		// Iterate over arbitrarily sized chunks coming in from the network.
-		for await (const chunk of withStreamIdleTimeout(this.body)) {
+		for await (const chunk of this.body) {
 			if (await this.maybeCancel('after awaiting body chunk')) {
 				return;
 			}