Prompt to update PowerShell version

package.json

@@ -40,13 +40,17 @@
     "onView:PowerShellCommands"
   ],
   "dependencies": {
+    "node-fetch": "^2.6.0",
+    "semver": "^6.3.0",
     "vscode-extension-telemetry": "~0.1.2",
     "vscode-languageclient": "~5.2.1"
   },
   "devDependencies": {
     "@types/mocha": "~5.2.7",
     "@types/node": "~10.11.0",
+    "@types/node-fetch": "^2.5.0",
     "@types/rewire": "^2.5.28",
+    "@types/semver": "^6.0.1",
     "mocha": "~5.2.0",
     "mocha-junit-reporter": "~1.23.1",
     "mocha-multi-reporters": "~1.1.7",
@@ -575,6 +579,11 @@
           "type": "string",
           "description": "Specifies the PowerShell version name, as displayed by the 'PowerShell: Show Session Menu' command, used when the extension loads e.g \"Windows PowerShell (x86)\" or \"PowerShell Core 6 (x64)\"."
         },
+        "powershell.promptToUpdatePowerShell": {
+          "type": "boolean",
+          "description": "Specifies whether you should be prompted to update your version of PowerShell.",
+          "default": true
+        },
         "powershell.startAutomatically": {
           "type": "boolean",
           "default": true,

src/features/UpdatePowerShell.ts

@@ -0,0 +1,112 @@
+/*---------------------------------------------------------
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ *--------------------------------------------------------*/
+
+import fetch from "node-fetch";
+import { compare, parse, prerelease, SemVer } from "semver";
+import { MessageItem, window } from "vscode";
+import Settings = require("../settings");
+import { EvaluateRequestType } from "./Console";
+
+const PowerShellGitHubReleasesUrl =
+        "https://api.github.com/repos/PowerShell/PowerShell/releases/latest";
+const PowerShellGitHubRPrereleasesUrl =
+    "https://api.github.com/repos/PowerShell/PowerShell/releases";
+
+export class GitHubReleaseInformation {
+    public static async FetchLatestRelease(preview: boolean): Promise<GitHubReleaseInformation> {
+        // Fetch the latest PowerShell releases from GitHub.
+        let releaseJson: any;
+        if (preview) {
+            // This gets all releases and the first one is the latest prerelease if
+            // there is a prerelease version.
+            releaseJson = (await fetch(PowerShellGitHubRPrereleasesUrl)
+                .then((res) => res.json()))[0];
+        } else {
+            releaseJson = await fetch(PowerShellGitHubReleasesUrl)
+                .then((res) => res.json());
+        }
+
+        return new GitHubReleaseInformation(
+            releaseJson.tag_name, releaseJson.assets);
+    }
+
+    public version: SemVer;
+    public isPreview: boolean = false;
+    public assets: any[];
+
+    public constructor(version: string | SemVer, assets: any[] = []) {
+        this.version = parse(version);
+
+        if (prerelease(this.version)) {
+            this.isPreview = true;
+        }
+
+        this.assets = assets;
+    }
+}
+
+interface IUpdateMessageItem extends MessageItem {
+    id: number;
+}
+
+export async function InvokePowerShellUpdateCheck(
+    localVersion: SemVer, arch: string, release: GitHubReleaseInformation) {
+    const options: IUpdateMessageItem[] = [
+        {
+            id: 0,
+            title: "Yes!",
+        },
+        {
+            id: 1,
+            title: "Not now.",
+        },
+        {
+            id: 2,
+            title: "Never...",
+        },
+    ];
+
+    if (compare(release.version, localVersion) > 0) {
+        const result = await window.showInformationMessage(
+            `You have an old version of PowerShell (${
+            localVersion.raw
+        }). The current latest release is ${
+            release.version.raw
+        }. Would you like to update the version?`, ...options);
+
+        // Yes choice.
+        if (result.id === 0) {
+            let script: string;
+            if (process.platform === "win32") {
+                const msiMatcher = arch === "x86" ?
+                    "win-x86.msi" : "win-x64.msi";
+
+                const assetUrl = release.assets.filter((asset: any) =>
+                    asset.name.indexOf(msiMatcher) >= 0)[0].url;
+
+                // Grab MSI and run it.
+                // tslint:disable-next-line: max-line-length
+                script = `$tmpMsiPath = Microsoft.PowerShell.Management\\Join-Path ([System.IO.Path]::GetTempPath()) "pwsh.msi";
+Microsoft.PowerShell.Utility\\Invoke-RestMethod -Uri ${assetUrl} -OutFile $tmpMsiPath;
+Microsoft.PowerShell.Management\\Invoke-Item $tmpMsiPath;`;
+
+            } else if (process.platform === "darwin") {
+                script = "brew cask upgrade powershell";
+                if (release.isPreview) {
+                    script = "brew cask upgrade powershell-preview";
+                }
+            } else if (process.platform === "linux") {
+                window.showWarningMessage(
+                    "Update through VS Code not supported on Linux.");
+                return;
+            }
+            await this.languageServerClient.sendRequest(EvaluateRequestType, {
+                expression: script,
+            });
+        // Never choice.
+        } else if (result.id === 2) {
+            await Settings.change("promptToUpdatePowerShell", false, true);
+        }
+    }
+}