Fix: Exp enable completions and NES fetcher (#1245)

chrmarti · web-flow · commit 5c1d517a6ed0 · 2025-10-07T07:46:27.000Z
diff --git a/package.json b/package.json
@@ -5,7 +5,7 @@
 	"version": "0.33.0",
 	"build": "1",
 	"internalAIKey": "1058ec22-3c95-4951-8443-f26c1f325911",
-	"completionsCore": "74943bef72acfd94931c6ec2c1c7420c8c932336",
+	"completionsCore": "07be33f7faf935076909fc82bc0f5ac578cca983",
 	"completionsCoreVersion": "1.372.0",
 	"internalLargeStorageAriaKey": "ec712b3202c5462fb6877acae7f1f9d7-c19ad55e-3e3c-4f99-984b-827f6d95bd9e-6917",
 	"ariaKey": "0c6ae279ed8443289764825290e4f9e2-1a736e7c-1324-4338-be46-fc2a58ae4d14-7255",
@@ -3128,6 +3128,30 @@
 						"tags": [
 							"experimental"
 						]
+					},
+					"github.copilot.chat.completionsFetcher": {
+						"type": ["string", "null"],
+						"markdownDescription": "%github.copilot.config.completionsFetcher%",
+						"tags": [
+							"experimental",
+							"onExp"
+						],
+						"enum": [
+							"electron-fetch",
+							"node-fetch"
+						]
+					},
+					"github.copilot.chat.nesFetcher": {
+						"type": ["string", "null"],
+						"markdownDescription": "%github.copilot.config.nesFetcher%",
+						"tags": [
+							"experimental",
+							"onExp"
+						],
+						"enum": [
+							"electron-fetch",
+							"node-fetch"
+						]
 					}
 				}
 			}
diff --git a/package.nls.json b/package.nls.json
@@ -305,5 +305,7 @@
 	"github.copilot.config.useResponsesApi": "Use the Responses API instead of the Chat Completions API when supported. Enables reasoning and reasoning summaries.\n\n**Note**: This is an experimental feature that is not yet activated for all users.",
 	"github.copilot.config.responsesApiReasoningEffort": "Sets the reasoning effort used for the Responses API. Requires `#github.copilot.chat.useResponsesApi#`.",
 	"github.copilot.config.responsesApiReasoningSummary": "Sets the reasoning summary style used for the Responses API. Requires `#github.copilot.chat.useResponsesApi#`.",
-	"github.copilot.config.executePrompt.enabled": "The executePrompt tool enables the agent to execute tasks in a separate, isolated context."
+	"github.copilot.config.executePrompt.enabled": "The executePrompt tool enables the agent to execute tasks in a separate, isolated context.",
+	"github.copilot.config.completionsFetcher": "Sets the fetcher used for the inline completions.",
+	"github.copilot.config.nesFetcher": "Sets the fetcher used for the next edit suggestions."
 }
diff --git a/src/extension/xtab/node/xtabProvider.ts b/src/extension/xtab/node/xtabProvider.ts
@@ -547,6 +547,8 @@ export class XtabProvider implements IStatelessNextEditProvider {
 	) {
 		const tracer = parentTracer.sub('streamEdits');
 
+		const useFetcher = this.configService.getExperimentBasedConfig(ConfigKey.NextEditSuggestionsFetcher, this.expService) || undefined;
+
 		const fetchStreamSource = new FetchStreamSource();
 
 		const fetchRequestStopWatch = new StopWatch();
@@ -592,6 +594,7 @@ export class XtabProvider implements IStatelessNextEditProvider {
 				telemetryProperties: {
 					requestId: request.id,
 				},
+				useFetcher,
 			},
 			cancellationToken,
 		);
diff --git a/src/platform/configuration/common/configurationService.ts b/src/platform/configuration/common/configurationService.ts
@@ -20,6 +20,7 @@ import { ResponseProcessor } from '../../inlineEdits/common/responseProcessor';
 import { AlternativeNotebookFormat } from '../../notebook/common/alternativeContentFormat';
 import { IExperimentationService } from '../../telemetry/common/nullExperimentationService';
 import { IValidator, vBoolean, vString } from './validator';
+import { FetcherId } from '../../networking/common/fetcherService';
 
 export const CopilotConfigPrefix = 'github.copilot';
 
@@ -811,6 +812,9 @@ export namespace ConfigKey {
 	export const GrokCodeAlternatePrompt = defineExpSetting<string>('chat.grokCodeAlternatePrompt', 'default');
 	export const ClaudeSonnet45AlternatePrompt = defineExpSetting<string>('chat.claudeSonnet45AlternatePrompt', 'default');
 	export const ExecutePromptEnabled = defineSetting<boolean>('chat.executePrompt.enabled', false);
+
+	export const CompletionsFetcher = defineExpSetting<FetcherId | undefined>('chat.completionsFetcher', undefined);
+	export const NextEditSuggestionsFetcher = defineExpSetting<FetcherId | undefined>('chat.nesFetcher', undefined);
 }
 
 export function getAllConfigKeys(): string[] {
diff --git a/src/platform/networking/node/fetcherFallback.ts b/src/platform/networking/node/fetcherFallback.ts
@@ -5,19 +5,28 @@
 
 import { Readable } from 'stream';
 import { ILogService } from '../../log/common/logService';
-import { FetchOptions, Response } from '../common/fetcherService';
+import { FetcherId, FetchOptions, Response } from '../common/fetcherService';
 import { IFetcher } from '../common/networking';
+import { Config, ConfigKey, IConfigurationService } from '../../configuration/common/configurationService';
 
 
-export async function fetchWithFallbacks(availableFetchers: readonly IFetcher[], url: string, options: FetchOptions, logService: ILogService): Promise<{ response: Response; updatedFetchers?: IFetcher[] }> {
+const fetcherConfigKeys: Record<FetcherId, Config<boolean>> = {
+	'electron-fetch': ConfigKey.Shared.DebugUseElectronFetcher,
+	'node-fetch': ConfigKey.Shared.DebugUseNodeFetchFetcher,
+	'node-http': ConfigKey.Shared.DebugUseNodeFetcher,
+};
+
+export async function fetchWithFallbacks(availableFetchers: readonly IFetcher[], url: string, options: FetchOptions, knownBadFetchers: Set<string>, configurationService: IConfigurationService, logService: ILogService): Promise<{ response: Response; updatedFetchers?: IFetcher[]; updatedKnownBadFetchers?: Set<string> }> {
 	if (options.retryFallbacks && availableFetchers.length > 1) {
 		let firstResult: { ok: boolean; response: Response } | { ok: false; err: any } | undefined;
+		const updatedKnownBadFetchers = new Set<string>();
 		for (const fetcher of availableFetchers) {
 			const result = await tryFetch(fetcher, url, options, logService);
 			if (fetcher === availableFetchers[0]) {
 				firstResult = result;
 			}
 			if (!result.ok) {
+				updatedKnownBadFetchers.add(fetcher.getUserAgentLibrary());
 				continue;
 			}
 			if (fetcher !== availableFetchers[0]) {
@@ -29,7 +38,7 @@ export async function fetchWithFallbacks(availableFetchers: readonly IFetcher[],
 				const updatedFetchers = availableFetchers.slice();
 				updatedFetchers.splice(updatedFetchers.indexOf(fetcher), 1);
 				updatedFetchers.unshift(fetcher);
-				return { response: result.response, updatedFetchers };
+				return { response: result.response, updatedFetchers, updatedKnownBadFetchers };
 			}
 			return { response: result.response };
 		}
@@ -38,12 +47,23 @@ export async function fetchWithFallbacks(availableFetchers: readonly IFetcher[],
 		}
 		throw firstResult!.err;
 	}
-	const fetcher = options.useFetcher && availableFetchers.find(f => f.getUserAgentLibrary() === options.useFetcher) || availableFetchers[0];
+	let fetcher = availableFetchers[0];
 	if (options.useFetcher) {
-		if (options.useFetcher === fetcher.getUserAgentLibrary()) {
-			logService.debug(`FetcherService: using ${options.useFetcher} as requested.`);
+		if (knownBadFetchers.has(options.useFetcher)) {
+			logService.trace(`FetcherService: not using requested fetcher ${options.useFetcher} as it is known to be failing, using ${fetcher.getUserAgentLibrary()} instead.`);
 		} else {
-			logService.info(`FetcherService: could not find requested fetcher ${options.useFetcher}, using ${fetcher.getUserAgentLibrary()} instead.`);
+			const configKey = fetcherConfigKeys[options.useFetcher];
+			if (configKey && configurationService.inspectConfig(configKey)?.globalValue === false) {
+				logService.trace(`FetcherService: not using requested fetcher ${options.useFetcher} as it is disabled in user settings, using ${fetcher.getUserAgentLibrary()} instead.`);
+			} else {
+				const requestedFetcher = availableFetchers.find(f => f.getUserAgentLibrary() === options.useFetcher);
+				if (requestedFetcher) {
+					fetcher = requestedFetcher;
+					logService.trace(`FetcherService: using ${options.useFetcher} as requested.`);
+				} else {
+					logService.info(`FetcherService: could not find requested fetcher ${options.useFetcher}, using ${fetcher.getUserAgentLibrary()} instead.`);
+				}
+			}
 		}
 	}
 	return { response: await fetcher.fetch(url, options) };
diff --git a/src/platform/networking/test/node/fetcherFallback.spec.ts b/src/platform/networking/test/node/fetcherFallback.spec.ts
@@ -8,13 +8,18 @@ import { Readable } from 'stream';
 import { suite, test } from 'vitest';
 import { FakeHeaders } from '../../../test/node/fetcher';
 import { TestLogService } from '../../../testing/common/testLogService';
-import { FetchOptions, Response } from '../../common/fetcherService';
+import { FetcherId, FetchOptions, Response } from '../../common/fetcherService';
 import { IFetcher } from '../../common/networking';
 import { fetchWithFallbacks } from '../../node/fetcherFallback';
+import { DefaultsOnlyConfigurationService } from '../../../configuration/common/defaultsOnlyConfigurationService';
+import { InMemoryConfigurationService } from '../../../configuration/test/common/inMemoryConfigurationService';
+import { ConfigKey } from '../../../configuration/common/configurationService';
 
 suite('FetcherFallback Test Suite', function () {
 
+	const knownBadFetchers = new Set<FetcherId>();
 	const logService = new TestLogService();
+	const configurationService = new DefaultsOnlyConfigurationService();
 	const someHTML = '<html>...</html>';
 	const someJSON = '{"key": "value"}';
 
@@ -24,9 +29,10 @@ suite('FetcherFallback Test Suite', function () {
 			{ name: 'fetcher2', response: createFakeResponse(200, someJSON) },
 		];
 		const testFetchers = createTestFetchers(fetcherSpec);
-		const { response, updatedFetchers } = await fetchWithFallbacks(testFetchers.fetchers, 'https://example.com', { expectJSON: true, retryFallbacks: true }, logService);
+		const { response, updatedFetchers, updatedKnownBadFetchers } = await fetchWithFallbacks(testFetchers.fetchers, 'https://example.com', { expectJSON: true, retryFallbacks: true }, knownBadFetchers, configurationService, logService);
 		assert.deepStrictEqual(testFetchers.calls.map(c => c.name), fetcherSpec.slice(0, 1).map(f => f.name)); // only first fetcher called
 		assert.strictEqual(updatedFetchers, undefined);
+		assert.strictEqual(updatedKnownBadFetchers, undefined);
 		assert.strictEqual(response.status, 200);
 		const json = await response.json();
 		assert.deepStrictEqual(json, JSON.parse(someJSON));
@@ -39,11 +45,14 @@ suite('FetcherFallback Test Suite', function () {
 			{ name: 'fetcher1', response: createFakeResponse(200, someHTML) },
 		];
 		const testFetchers = createTestFetchers(fetcherSpec);
-		const { response, updatedFetchers } = await fetchWithFallbacks(testFetchers.fetchers, 'https://example.com', { expectJSON: true, retryFallbacks: true }, logService);
+		const { response, updatedFetchers, updatedKnownBadFetchers } = await fetchWithFallbacks(testFetchers.fetchers, 'https://example.com', { expectJSON: true, retryFallbacks: true }, knownBadFetchers, configurationService, logService);
 		assert.deepStrictEqual(testFetchers.calls.map(c => c.name), fetcherSpec.map(f => f.name));
 		assert.ok(updatedFetchers);
 		assert.strictEqual(updatedFetchers[0], testFetchers.fetchers[1]);
 		assert.strictEqual(updatedFetchers[1], testFetchers.fetchers[0]);
+		assert.ok(updatedKnownBadFetchers);
+		assert.strictEqual(updatedKnownBadFetchers.size, 1);
+		assert.strictEqual(updatedKnownBadFetchers.has('fetcher1'), true);
 		assert.strictEqual(response.status, 200);
 		const json = await response.json();
 		assert.deepStrictEqual(json, JSON.parse(someJSON));
@@ -55,9 +64,10 @@ suite('FetcherFallback Test Suite', function () {
 			{ name: 'fetcher2', response: createFakeResponse(401, someJSON) },
 		];
 		const testFetchers = createTestFetchers(fetcherSpec);
-		const { response, updatedFetchers } = await fetchWithFallbacks(testFetchers.fetchers, 'https://example.com', { expectJSON: true, retryFallbacks: true }, logService);
+		const { response, updatedFetchers, updatedKnownBadFetchers } = await fetchWithFallbacks(testFetchers.fetchers, 'https://example.com', { expectJSON: true, retryFallbacks: true }, knownBadFetchers, configurationService, logService);
 		assert.deepStrictEqual(testFetchers.calls.map(c => c.name), fetcherSpec.map(f => f.name));
 		assert.strictEqual(updatedFetchers, undefined);
+		assert.strictEqual(updatedKnownBadFetchers, undefined);
 		assert.strictEqual(response.status, 407);
 		const text = await response.text();
 		assert.deepStrictEqual(text, someHTML);
@@ -70,14 +80,64 @@ suite('FetcherFallback Test Suite', function () {
 		];
 		const testFetchers = createTestFetchers(fetcherSpec);
 		try {
-			await fetchWithFallbacks(testFetchers.fetchers, 'https://example.com', { expectJSON: true, retryFallbacks: true }, logService);
+			await fetchWithFallbacks(testFetchers.fetchers, 'https://example.com', { expectJSON: true, retryFallbacks: true }, knownBadFetchers, configurationService, logService);
 			assert.fail('Expected to throw');
 		} catch (err) {
 			assert.ok(err instanceof Error);
 			assert.strictEqual(err.message, 'fetcher1 error');
 			assert.deepStrictEqual(testFetchers.calls.map(c => c.name), fetcherSpec.map(f => f.name));
 		}
 	});
+
+	test('useFetcher option selects second fetcher', async function () {
+		const fetcherSpec = [
+			{ name: 'electron-fetch', response: createFakeResponse(200, someJSON) },
+			{ name: 'node-fetch', response: createFakeResponse(200, someJSON) },
+		];
+		const testFetchers = createTestFetchers(fetcherSpec);
+		const { response, updatedFetchers, updatedKnownBadFetchers } = await fetchWithFallbacks(testFetchers.fetchers, 'https://example.com', { useFetcher: 'node-fetch' }, knownBadFetchers, configurationService, logService);
+		assert.deepStrictEqual(testFetchers.calls.map(c => c.name), ['node-fetch']); // only second fetcher called
+		assert.strictEqual(updatedFetchers, undefined);
+		assert.strictEqual(updatedKnownBadFetchers, undefined);
+		assert.strictEqual(response.status, 200);
+		const json = await response.json();
+		assert.deepStrictEqual(json, JSON.parse(someJSON));
+	});
+
+	test('useFetcher option falls back to first fetcher when requested fetcher is disabled', async function () {
+		const fetcherSpec = [
+			{ name: 'electron-fetch', response: createFakeResponse(200, someJSON) },
+			{ name: 'node-fetch', response: createFakeResponse(200, someJSON) },
+		];
+		const testFetchers = createTestFetchers(fetcherSpec);
+		const configServiceWithDisabledNodeFetch = new InMemoryConfigurationService(
+			configurationService,
+			new Map([[ConfigKey.Shared.DebugUseNodeFetchFetcher, false]])
+		);
+		const { response, updatedFetchers, updatedKnownBadFetchers } = await fetchWithFallbacks(testFetchers.fetchers, 'https://example.com', { useFetcher: 'node-fetch' }, knownBadFetchers, configServiceWithDisabledNodeFetch, logService);
+		assert.deepStrictEqual(testFetchers.calls.map(c => c.name), ['electron-fetch']); // first fetcher used instead
+		assert.strictEqual(updatedFetchers, undefined);
+		assert.strictEqual(updatedKnownBadFetchers, undefined);
+		assert.strictEqual(response.status, 200);
+		const json = await response.json();
+		assert.deepStrictEqual(json, JSON.parse(someJSON));
+	});
+
+	test('useFetcher option falls back to first fetcher when requested fetcher is known bad', async function () {
+		const fetcherSpec = [
+			{ name: 'electron-fetch', response: createFakeResponse(200, someJSON) },
+			{ name: 'node-fetch', response: createFakeResponse(200, someJSON) },
+		];
+		const testFetchers = createTestFetchers(fetcherSpec);
+		const knownBadFetchersWithNodeFetch = new Set<FetcherId>(['node-fetch']);
+		const { response, updatedFetchers, updatedKnownBadFetchers } = await fetchWithFallbacks(testFetchers.fetchers, 'https://example.com', { useFetcher: 'node-fetch' }, knownBadFetchersWithNodeFetch, configurationService, logService);
+		assert.deepStrictEqual(testFetchers.calls.map(c => c.name), ['electron-fetch']); // first fetcher used instead
+		assert.strictEqual(updatedFetchers, undefined);
+		assert.strictEqual(updatedKnownBadFetchers, undefined);
+		assert.strictEqual(response.status, 200);
+		const json = await response.json();
+		assert.deepStrictEqual(json, JSON.parse(someJSON));
+	});
 });
 
 function createTestFetchers(fetcherSpecs: Array<{ name: string; response: Response | Error }>) {
diff --git a/src/platform/networking/vscode-node/fetcherServiceImpl.ts b/src/platform/networking/vscode-node/fetcherServiceImpl.ts
@@ -18,6 +18,7 @@ export class FetcherService implements IFetcherService {
 
 	declare readonly _serviceBrand: undefined;
 	private _availableFetchers: readonly IFetcher[] | undefined;
+	private _knownBadFetchers = new Set<string>();
 	private _experimentationService: IExperimentationService | undefined;
 
 	constructor(
@@ -88,10 +89,13 @@ export class FetcherService implements IFetcherService {
 	}
 
 	async fetch(url: string, options: FetchOptions): Promise<Response> {
-		const { response: res, updatedFetchers } = await fetchWithFallbacks(this._getAvailableFetchers(), url, options, this._logService);
+		const { response: res, updatedFetchers, updatedKnownBadFetchers } = await fetchWithFallbacks(this._getAvailableFetchers(), url, options, this._knownBadFetchers, this._configurationService, this._logService);
 		if (updatedFetchers) {
 			this._availableFetchers = updatedFetchers;
 		}
+		if (updatedKnownBadFetchers) {
+			this._knownBadFetchers = updatedKnownBadFetchers;
+		}
 		return res;
 	}
 

Original file line number	Diff line number	Diff line change
`@@ -305,5 +305,7 @@`
`305`	`305`	`"github.copilot.config.useResponsesApi": "Use the Responses API instead of the Chat Completions API when supported. Enables reasoning and reasoning summaries.\n\nNote: This is an experimental feature that is not yet activated for all users.",`
`306`	`306`	"github.copilot.config.responsesApiReasoningEffort": "Sets the reasoning effort used for the Responses API. Requires `#github.copilot.chat.useResponsesApi#`.",
`307`	`307`	"github.copilot.config.responsesApiReasoningSummary": "Sets the reasoning summary style used for the Responses API. Requires `#github.copilot.chat.useResponsesApi#`.",
`308`		`- "github.copilot.config.executePrompt.enabled": "The executePrompt tool enables the agent to execute tasks in a separate, isolated context."`
	`308`	`+ "github.copilot.config.executePrompt.enabled": "The executePrompt tool enables the agent to execute tasks in a separate, isolated context.",`
	`309`	`+ "github.copilot.config.completionsFetcher": "Sets the fetcher used for the inline completions.",`
	`310`	`+ "github.copilot.config.nesFetcher": "Sets the fetcher used for the next edit suggestions."`
`309`	`311`	`}`
Original file line number	Diff line number	Diff line change
`@@ -18,6 +18,7 @@ export class FetcherService implements IFetcherService {`
`18`	`18`
`19`	`19`	`declare readonly _serviceBrand: undefined;`
`20`	`20`	`private _availableFetchers: readonly IFetcher[] \| undefined;`
	`21`	`+ private _knownBadFetchers = new Set<string>();`
`21`	`22`	`private _experimentationService: IExperimentationService \| undefined;`
`22`	`23`
`23`	`24`	`constructor(`
`@@ -88,10 +89,13 @@ export class FetcherService implements IFetcherService {`
`88`	`89`	`}`
`89`	`90`
`90`	`91`	`async fetch(url: string, options: FetchOptions): Promise<Response> {`
`91`		`- const { response: res, updatedFetchers } = await fetchWithFallbacks(this._getAvailableFetchers(), url, options, this._logService);`
	`92`	`+ const { response: res, updatedFetchers, updatedKnownBadFetchers } = await fetchWithFallbacks(this._getAvailableFetchers(), url, options, this._knownBadFetchers, this._configurationService, this._logService);`
`92`	`93`	`if (updatedFetchers) {`
`93`	`94`	`this._availableFetchers = updatedFetchers;`
`94`	`95`	`}`
	`96`	`+ if (updatedKnownBadFetchers) {`
	`97`	`+ this._knownBadFetchers = updatedKnownBadFetchers;`
	`98`	`+ }`
`95`	`99`	`return res;`
`96`	`100`	`}`
`97`	`101`