Implements "yarn policies set-version"

CHANGELOG.md

@@ -4,6 +4,10 @@ Please add one entry in this file for each change in Yarn's behavior. Use the sa
 
 ## Master
 
+- Implements `yarn policies set-version [range]`. Check [the documentation]() for usage & tips.
+
+  [#6673](https://github.com/yarnpkg/yarn/pull/6673) - [**Maël Nison**](https://twitter.com/arcanis)
+
 - Fixes a resolution issue when a package had an invalid `main` entry
 
   [#6682](https://github.com/yarnpkg/yarn/pull/6682) - [**Maël Nison**](https://twitter.com/arcanis)

src/cli/commands/index.js

@@ -32,6 +32,7 @@ import * as node from './node.js';
 import * as outdated from './outdated.js';
 import * as owner from './owner.js';
 import * as pack from './pack.js';
+import * as policies from './policies.js';
 import * as publish from './publish.js';
 import * as remove from './remove.js';
 import * as run from './run.js';
@@ -78,6 +79,7 @@ const commands = {
   outdated,
   owner,
   pack,
+  policies,
   prune: buildUseless("The prune command isn't necessary. `yarn install` will prune extraneous packages."),
   publish,
   remove,

src/cli/commands/policies.js

@@ -0,0 +1,160 @@
+/* @flow */
+
+import type {Reporter} from '../../reporters/index.js';
+import type Config from '../../config.js';
+import buildSubCommands from './_build-sub-commands.js';
+import {getRcConfigForCwd} from '../../rc.js';
+import * as fs from '../../util/fs.js';
+import {stringify} from '../../lockfile';
+
+const chalk = require('chalk');
+const invariant = require('invariant');
+const path = require('path');
+const semver = require('semver');
+
+type ReleaseAsset = {|
+  id: any,
+
+  name: string,
+  browser_download_url: string,
+|};
+
+type Release = {|
+  id: any,
+
+  draft: boolean,
+  prerelease: boolean,
+
+  tag_name: string,
+  version: {|
+    version: string,
+  |},
+
+  assets: Array<ReleaseAsset>,
+|};
+
+function getBundleAsset(release: Release): ?ReleaseAsset {
+  return release.assets.find(asset => {
+    return asset.name.match(/^yarn-[0-9]+\.[0-9]+\.[0-9]+\.js$/);
+  });
+}
+
+type FetchReleasesOptions = {|
+  includePrereleases: boolean,
+|};
+
+async function fetchReleases(
+  config: Config,
+  {includePrereleases = false}: FetchReleasesOptions = {},
+): Promise<Array<Release>> {
+  const request: Array<Release> = await config.requestManager.request({
+    url: `https://api.github.com/repos/yarnpkg/yarn/releases`,
+    json: true,
+  });
+
+  const releases = request.filter(release => {
+    if (release.draft) {
+      return false;
+    }
+
+    if (release.prerelease && !includePrereleases) {
+      return false;
+    }
+
+    // $FlowFixMe
+    release.version = semver.coerce(release.tag_name);
+
+    if (!release.version) {
+      return false;
+    }
+
+    if (!getBundleAsset(release)) {
+      return false;
+    }
+
+    return true;
+  });
+
+  releases.sort((a, b) => {
+    // $FlowFixMe
+    return -semver.compare(a.version, b.version);
+  });
+
+  return releases;
+}
+
+function fetchBundle(config: Config, url: string): Promise<Buffer> {
+  return config.requestManager.request({
+    url,
+    buffer: true,
+  });
+}
+
+export function hasWrapper(flags: Object, args: Array<string>): boolean {
+  return false;
+}
+
+const {run, setFlags, examples} = buildSubCommands('policies', {
+  async setVersion(config: Config, reporter: Reporter, flags: Object, args: Array<string>): Promise<void> {
+    let range = args[0] || 'latest';
+    let allowRc = flags.rc;
+
+    reporter.log(`Resolving ${chalk.yellow(range)} to a url...`);
+
+    if (range === 'rc') {
+      range = 'latest';
+      allowRc = true;
+    }
+
+    if (range === 'latest') {
+      range = '*';
+    }
+
+    let bundleUrl;
+    let bundleVersion;
+
+    if (range === 'nightly' || range === 'nightlies') {
+      bundleUrl = 'https://nightly.yarnpkg.com/latest.js';
+      bundleVersion = 'nightly';
+    } else {
+      const releases = await fetchReleases(config, {
+        includePrereleases: allowRc,
+      });
+
+      const release = releases.find(release => {
+        // $FlowFixMe
+        return semver.satisfies(release.version, range);
+      });
+
+      if (!release) {
+        throw new Error(`Release not found: ${range}`);
+      }
+
+      const asset = getBundleAsset(release);
+      invariant(asset, 'The bundle asset should exist');
+
+      bundleUrl = asset.browser_download_url;
+      bundleVersion = release.version.version;
+    }
+
+    reporter.log(`Downloading ${chalk.green(bundleUrl)}...`);
+
+    const bundle = await fetchBundle(config, bundleUrl);
+    const rc = getRcConfigForCwd(config.lockfileFolder, []);
+
+    const yarnPath = path.resolve(config.lockfileFolder, `.yarn/releases/yarn-${bundleVersion}.js`);
+    reporter.log(`Saving it into ${chalk.magenta(yarnPath)}...`);
+    await fs.mkdirp(path.dirname(yarnPath));
+    await fs.writeFile(yarnPath, bundle);
+    await fs.chmod(yarnPath, 0o755);
+
+    const rcPath = `${config.lockfileFolder}/.yarnrc`;
+    reporter.log(`Updating ${chalk.magenta(rcPath)}...`);
+    rc['yarn-path'] = path.relative(config.lockfileFolder, yarnPath);
+    await fs.writeFilePreservingEol(rcPath, `${stringify(rc)}\n`);
+
+    reporter.log(`Done!`);
+  },
+});
+
+export {run, setFlags, examples};

src/registries/yarn-registry.js

@@ -31,7 +31,8 @@ export const DEFAULTS = {
   'user-agent': [`yarn/${version}`, 'npm/?', `node/${process.version}`, process.platform, process.arch].join(' '),
 };
 
-const RELATIVE_KEYS = ['yarn-offline-mirror', 'cache-folder', 'offline-cache-folder'];
+const RELATIVE_KEYS = ['yarn-offline-mirror', 'cache-folder', 'offline-cache-folder', 'yarn-path'];
+const FOLDER_KEY = ['yarn-offline-mirror', 'cache-folder', 'offline-cache-folder'];
 
 const npmMap = {
   'version-git-sign': 'sign-git-tag',
@@ -96,7 +97,10 @@ export default class YarnRegistry extends NpmRegistry {
 
         if (!this.config[key] && valueLoc) {
           const resolvedLoc = (config[key] = path.resolve(path.dirname(loc), valueLoc));
-          await fs.mkdirp(resolvedLoc);
+
+          if (FOLDER_KEY.includes(key)) {
+            await fs.mkdirp(resolvedLoc);
+          }
         }
       }
 

src/util/fs.js

@@ -28,7 +28,9 @@ export const lockQueue = new BlockingQueue('fs lock');
 
 export const readFileBuffer = promisify(fs.readFile);
 export const open: (path: string, flags: string, mode?: number) => Promise<Array<string>> = promisify(fs.open);
-export const writeFile: (path: string, data: string, options?: Object) => Promise<void> = promisify(fs.writeFile);
+export const writeFile: (path: string, data: string | Buffer, options?: Object) => Promise<void> = promisify(
+  fs.writeFile,
+);
 export const readlink: (path: string, opts: void) => Promise<string> = promisify(fs.readlink);
 export const realpath: (path: string, opts: void) => Promise<string> = promisify(fs.realpath);
 export const readdir: (path: string, opts: void) => Promise<Array<string>> = promisify(fs.readdir);