Add self update

src/cli/aliases.js

@@ -3,4 +3,5 @@
 export default ({
   'upgrade-interactive': 'upgradeInteractive',
   'generate-lock-entry': 'generateLockEntry',
+  'self-upgrade': 'selfUpgrade',
 }: {[key: string]: string});

src/cli/commands/index.js

@@ -36,6 +36,7 @@ import * as policies from './policies.js';
 import * as publish from './publish.js';
 import * as remove from './remove.js';
 import * as run from './run.js';
+import * as selfUpgrade from './self-upgrade.js';
 import * as tag from './tag.js';
 import * as team from './team.js';
 import * as unplug from './unplug.js';
@@ -84,6 +85,7 @@ const commands = {
   publish,
   remove,
   run,
+  selfUpgrade,
   tag,
   team,
   unplug,

src/cli/commands/install.js

@@ -87,7 +87,7 @@ type Flags = {
  * Try and detect the installation method for Yarn and provide a command to update it with.
  */
 
-function getUpdateCommand(installationMethod: InstallationMethod): ?string {
+export function getUpdateCommand(installationMethod: InstallationMethod): ?string {
   if (installationMethod === 'tar') {
     return `curl --compressed -o- -L ${constants.YARN_INSTALLER_SH} | bash`;
   }

src/cli/commands/self-upgrade.js

@@ -0,0 +1,62 @@
+/* @flow */
+
+import semver from 'semver';
+import type Config from '../../config.js';
+import {SELF_UPDATE_VERSION_URL} from '../../constants.js';
+import type {Reporter} from '../../reporters/index.js';
+import {getInstallationMethod} from '../../util/yarn-version.js';
+import {getUpdateCommand} from './install';
+import {execCommand} from '../../util/execute-lifecycle-script.js';
+
+export const noArguments = true;
+export const requireLockfile = false;
+
+export function setFlags(commander: Object) {
+  commander.description('Upgrades yarn according to the installation method');
+}
+
+export function hasWrapper(commander: Object, args: Array<string>): boolean {
+  return true;
+}
+
+export async function run(config: Config, reporter: Reporter, flags: Object, args: Array<string>): Promise<void> {
+  const currentVersion = flags.version();
+  const latestVersion = await config.requestManager.request({
+    url: SELF_UPDATE_VERSION_URL,
+    headers: {
+      Accept: 'text/plain',
+    },
+  });
+
+  // Check if we already use the latest or a newer version
+  if (semver.compare(currentVersion, latestVersion) >= 0) {
+    reporter.info('already on latest version or higher');
+    return;
+  }
+
+  const installationMethod = await getInstallationMethod();
+
+  reporter.info(installationMethod);
+
+  if (installationMethod === 'unknown') {
+    reporter.info('installation method could not be identified');
+    return;
+  }
+
+  const command = getUpdateCommand(installationMethod);
+  if (command) {
+    reporter.info(`installation method: , ${installationMethod}`);
+
+    reporter.info('running');
+
+    await execCommand({
+      stage: 'self-upgrade',
+      config,
+      cmd: command,
+      cwd: config.cwd,
+      isInteractive: true,
+    });
+  } else {
+    reporter.info('could not find command for instalation method');
+  }
+}

src/lockfile/parse.js

@@ -186,7 +186,7 @@ class Parser {
       if (version > LOCKFILE_VERSION) {
         throw new MessageError(
           `Can't install from a lockfile of version ${version} as you're on an old yarn version that only supports ` +
-            `versions up to ${LOCKFILE_VERSION}. Run \`$ yarn self-update\` to upgrade to the latest version.`,
+            `versions up to ${LOCKFILE_VERSION}. Run \`$ yarn self-upgrade\` to upgrade to the latest version.`,
         );
       }
     }