utils: Fixes for the copilot work in ACA

utils/index.d.ts

@@ -8,7 +8,6 @@
 import type { Environment } from '@azure/ms-rest-azure-env';
 import type { AzExtResourceType, AzureAuthentication, AzureResource, AzureSubscription, ResourceModelBase } from '@microsoft/vscode-azureresources-api';
 import type * as duration from 'dayjs/plugin/duration';
-import type * as vscode from 'vscode';
 import type * as vscodeTypes from 'vscode';
 import { AuthenticationSession, AuthenticationWwwAuthenticateRequest, CancellationToken, CancellationTokenSource, Command, Disposable, Event, ExtensionContext, FileChangeEvent, FileChangeType, FileStat, FileSystemProvider, FileType, InputBoxOptions, LanguageModelToolInvocationOptions, LanguageModelToolInvocationPrepareOptions, LanguageModelToolResult, LogLevel, LogOutputChannel, MarkdownString, MessageItem, MessageOptions, OpenDialogOptions, OutputChannel, PreparedToolInvocation, Progress, ProviderResult, QuickPickItem, TelemetryTrustedValue, TextDocumentShowOptions, ThemeIcon, TreeDataProvider, TreeItem, TreeItemCollapsibleState, TreeView, Uri, QuickPickOptions as VSCodeQuickPickOptions, WorkspaceFolder, WorkspaceFolderPickOptions } from 'vscode';
 import { TargetPopulation } from 'vscode-tas-client';

utils/package.json

@@ -73,7 +73,7 @@
         "dayjs": "^1.11.19",
         "html-to-text": "^9.0.5",
         "semver": "^7.7.4",
-        "vscode-tas-client": "^0.1.84"
+        "vscode-tas-client": "^0.2.1"
     },
     "peerDependencies": {
         "@azure/ms-rest-azure-env": "^2.0.0",

utils/src/copilot/copilot.ts

@@ -6,6 +6,7 @@
 import type { CopilotClient, CopilotSession } from "@github/copilot-sdk";
 import type * as vscode from "vscode";
 import { InvalidCopilotResponseError } from "../errors";
+import { ensureCopilotCliInstalled, getCopilotCliPath } from "./installCopilotCli";
 
 let client: CopilotClient | undefined;
 let session: CopilotSession | undefined;
@@ -14,10 +15,6 @@ async function loadCopilotSdk(): Promise<typeof import("@github/copilot-sdk")> {
     return await import("@github/copilot-sdk");
 }
 
-function getCopilotCliPath(): string {
-    return require.resolve(`@github/copilot-${process.platform}-${process.arch}`);
-}
-
 export function createPrimaryPromptToGetSingleQuickPickInput(picks: string[], placeholder?: string): string {
     return `
         Task: choose one pick.
@@ -83,6 +80,11 @@ export async function getCopilotSession(relevantContext?: string): Promise<Copil
         return session;
     }
 
+    const installed = await ensureCopilotCliInstalled();
+    if (!installed) {
+        throw new InvalidCopilotResponseError();
+    }
+
     const { CopilotClient } = await loadCopilotSdk();
     client = new CopilotClient({ cliPath: getCopilotCliPath() });
     session = await client.createSession({

utils/src/copilot/installCopilotCli.ts

@@ -3,7 +3,9 @@
 *  Licensed under the MIT License. See License.md in the project root for license information.
 *--------------------------------------------------------------------------------------------*/
 
-import { type CommandLineArgs, composeArgs, spawnStreamAsync, withArg } from "@microsoft/vscode-processutils";
+import { type CommandLineArgs, composeArgs, getSafeExecPath, spawnStreamAsync, withArg } from "@microsoft/vscode-processutils";
+import { existsSync } from "fs";
+import * as path from "path";
 import { Writable } from "stream";
 import * as vscode from "vscode";
 import { ext } from "../extensionVariables";
@@ -13,6 +15,61 @@ interface InstallCommand {
     args: CommandLineArgs;
 }
 
+/**
+ * Resolves the full filesystem path to the platform-specific `@github/copilot` binary,
+ * falling back to a globally installed `copilot` CLI on PATH.
+ *
+ * We must resolve a real, absolute file path because `CopilotClient` validates `cliPath`
+ * with `existsSync()` and does not search PATH for bare command names.
+ *
+ * @internal Exported for testing.
+ */
+export function getCopilotCliPath(): string {
+    try {
+        return require.resolve(`@github/copilot-${process.platform}-${process.arch}`);
+    } catch {
+        // The platform-specific binary package is not present. Fall back to a globally installed `copilot` CLI on PATH.
+        return resolveCopilotCliFromPath() ?? 'copilot';
+    }
+}
+
+/**
+ * Searches PATH for the `copilot` executable and returns its absolute path, or `undefined`
+ * if it cannot be found. Uses {@link getSafeExecPath} to resolve against PATH and verifies the
+ * result with `existsSync()`, then falls back to a manual PATH scan (which also resolves a real
+ * file path on non-Windows platforms, where `getSafeExecPath` returns the bare command name).
+ */
+function resolveCopilotCliFromPath(): string | undefined {
+    try {
+        const execPath = getSafeExecPath('copilot');
+        if (path.isAbsolute(execPath) && existsSync(execPath)) {
+            return execPath;
+        }
+    } catch {
+        // `copilot` was not found on PATH; fall through to a manual scan.
+    }
+
+    return scanPathForCopilot();
+}
+
+function scanPathForCopilot(): string | undefined {
+    const pathDirs = (process.env.PATH || '').split(path.delimiter).filter(dir => dir.length > 0);
+    const exeNames = process.platform === 'win32'
+        ? (process.env.PATHEXT || '.EXE;.CMD;.BAT').split(';').map(pathExt => `copilot${pathExt.trim().toLowerCase()}`)
+        : ['copilot'];
+
+    for (const dir of pathDirs) {
+        for (const exeName of exeNames) {
+            const candidate = path.join(dir, exeName);
+            if (existsSync(candidate)) {
+                return candidate;
+            }
+        }
+    }
+
+    return undefined;
+}
+
 export async function isCopilotCliInstalled(): Promise<boolean> {
     try {
         await spawnStreamAsync('copilot', composeArgs(withArg('--version'))(), {});

utils/src/errors.ts

@@ -25,7 +25,7 @@ export function isUserCancelledError(error: unknown): error is UserCancelledErro
 
 export class InvalidCopilotResponseError extends Error {
     constructor() {
-        super(vscode.l10n.t('Invalid input.'));
+        super(vscode.l10n.t('Unable to get a valid response from the GitHub Copilot CLI.'));
     }
 }