feat: Add external folder context for monorepos and full-stack workflows

package.json

@@ -1824,6 +1824,18 @@
 				"icon": "$(terminal)",
 				"category": "Copilot CLI"
 			},
+			{
+				"command": "github.copilot.chat.addExternalContext",
+				"title": "%github.copilot.command.addExternalContext%",
+				"category": "Chat",
+				"icon": "$(folder-library)"
+			},
+			{
+				"command": "github.copilot.chat.manageExternalContexts",
+				"title": "%github.copilot.command.manageExternalContexts%",
+				"category": "Chat",
+				"icon": "$(list-selection)"
+			},
 			{
 				"command": "github.copilot.chat.replay",
 				"title": "Start Chat Replay",

package.nls.json

@@ -30,6 +30,8 @@
 	"github.copilot.command.openUserPreferences": "Open User Preferences",
 	"github.copilot.command.openMemoryFolder": "Open Memory Folder",
 	"github.copilot.command.sendChatFeedback": "Send Chat Feedback",
+	"github.copilot.command.addExternalContext": "Add External Folder",
+	"github.copilot.command.manageExternalContexts": "Manage External Folders",
 	"github.copilot.command.buildLocalWorkspaceIndex": "Build Local Workspace Index",
 	"github.copilot.command.buildRemoteWorkspaceIndex": "Build Remote Workspace Index",
 	"github.copilot.viewsWelcome.signIn": {

src/extension/context/node/externalContextService.ts

@@ -0,0 +1,124 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as npath from 'path';
+import { createServiceIdentifier } from '../../../util/common/services';
+import { isEqual } from '../../../util/vs/base/common/resources';
+import { URI } from '../../../util/vs/base/common/uri';
+import { Emitter, Event } from '../../../util/vs/base/common/event';
+import { Disposable } from '../../../util/vs/base/common/lifecycle';
+import { isWindows } from '../../../util/vs/base/common/platform';
+
+const MAX_EXTERNAL_PATHS = 3;
+
+export const IExternalContextService = createServiceIdentifier<IExternalContextService>('IExternalContextService');
+
+export interface IExternalContextService {
+	readonly _serviceBrand: undefined;
+	readonly onDidChangeExternalContext: Event<void>;
+	readonly maxExternalPaths: number;
+	getExternalPaths(): readonly URI[];
+	addExternalPaths(paths: readonly URI[]): readonly URI[];
+	replaceExternalPaths(paths: readonly URI[]): void;
+	removeExternalPath(path: URI): void;
+	clear(): void;
+	isExternalPath(uri: URI): boolean;
+}
+
+export class ExternalContextService extends Disposable implements IExternalContextService {
+	declare readonly _serviceBrand: undefined;
+
+	private readonly _onDidChangeExternalContext = this._register(new Emitter<void>());
+	readonly onDidChangeExternalContext: Event<void> = this._onDidChangeExternalContext.event;
+
+	readonly maxExternalPaths = MAX_EXTERNAL_PATHS;
+
+	private readonly _paths = new Map<string, URI>();
+
+	getExternalPaths(): readonly URI[] {
+		return [...this._paths.values()];
+	}
+
+	addExternalPaths(paths: readonly URI[]): readonly URI[] {
+		const added: URI[] = [];
+		if (!paths.length) {
+			return added;
+		}
+
+		for (const path of paths) {
+			if (this._paths.size >= MAX_EXTERNAL_PATHS) {
+				break;
+			}
+			const key = path.toString();
+			if (!this._paths.has(key)) {
+				this._paths.set(key, path);
+				added.push(path);
+			}
+		}
+		if (added.length) {
+			this._onDidChangeExternalContext.fire();
+		}
+
+		return added;
+	}
+
+	replaceExternalPaths(paths: readonly URI[]): void {
+		this._paths.clear();
+		for (const path of paths) {
+			if (this._paths.size >= MAX_EXTERNAL_PATHS) {
+				break;
+			}
+			const key = path.toString();
+			if (!this._paths.has(key)) {
+				this._paths.set(key, path);
+			}
+		}
+		this._onDidChangeExternalContext.fire();
+	}
+
+	removeExternalPath(path: URI): void {
+		for (const [key, storedPath] of this._paths) {
+			if (isEqual(storedPath, path)) {
+				this._paths.delete(key);
+				this._onDidChangeExternalContext.fire();
+				return;
+			}
+		}
+	}
+
+	clear(): void {
+		if (this._paths.size === 0) {
+			return;
+		}
+		this._paths.clear();
+		this._onDidChangeExternalContext.fire();
+	}
+
+	isExternalPath(uri: URI): boolean {
+		const candidateComparable = this.toComparablePath(uri);
+		for (const stored of this._paths.values()) {
+			const storedComparable = this.toComparablePath(stored);
+
+			if (candidateComparable === storedComparable) {
+				return true;
+			}
+
+			if (this.isSubPath(candidateComparable, storedComparable) || this.isSubPath(storedComparable, candidateComparable)) {
+				return true;
+			}
+		}
+		return false;
+	}
+
+	private toComparablePath(uri: URI): string {
+		const normalized = npath.normalize(uri.fsPath);
+		return isWindows ? normalized.toLowerCase() : normalized;
+	}
+
+	private isSubPath(child: string, potentialParent: string): boolean {
+		const parentWithSep = potentialParent.endsWith(npath.sep) ? potentialParent : potentialParent + npath.sep;
+		return child.startsWith(parentWithSep);
+	}
+}

src/extension/context/node/test/externalContextService.spec.ts

@@ -0,0 +1,53 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as path from 'path';
+import { describe, expect, it } from 'vitest';
+import { URI } from '../../../../util/vs/base/common/uri';
+import { ExternalContextService } from '../externalContextService';
+
+function createUri(name: string): URI {
+	return URI.file(path.join(process.cwd(), 'external-context-tests', name));
+}
+
+describe('ExternalContextService', () => {
+	it('caps at max external paths', () => {
+		const service = new ExternalContextService();
+
+		service.addExternalPaths([
+			createUri('one'),
+			createUri('two'),
+			createUri('three'),
+			createUri('four')
+		]);
+
+		expect(service.getExternalPaths()).toHaveLength(service.maxExternalPaths);
+	});
+
+	it('fires change event when paths are added', () => {
+		const service = new ExternalContextService();
+		let fired = 0;
+
+		service.onDidChangeExternalContext(() => fired++);
+
+		service.addExternalPaths([createUri('one')]);
+
+		expect(fired).toBe(1);
+	});
+
+	it('removes paths and fires event', () => {
+		const service = new ExternalContextService();
+		const [added] = service.addExternalPaths([createUri('one')]);
+		let fired = 0;
+
+		service.onDidChangeExternalContext(() => fired++);
+
+		service.removeExternalPath(added);
+
+		expect(service.getExternalPaths()).toHaveLength(0);
+		expect(fired).toBe(1);
+	});
+});
+