Update yarn to the latest stable version and add dynamic-extensions plugin

.yarn/plugins/@rnx-kit/yarn-plugin-dynamic-extensions.cjs

@@ -0,0 +1,96 @@
+// @ts-check
+
+/**
+ * @import { Configuration, Hooks, Manifest, PackageExtensionData, Plugin } from "@yarnpkg/core";
+ * @import { PortablePath } from "@yarnpkg/fslib";
+ * @typedef {{ cwd: string; manifest: Manifest["raw"]; }} Workspace;
+ */
+
+const DYNAMIC_PACKAGE_EXTENSIONS_KEY = "dynamicPackageExtensions";
+
+// This module *must* be CommonJS because `actions/setup-node` (and probably
+// other GitHub actions) does not support ESM. Yarn itself does.
+exports.name = "@rnx-kit/yarn-plugin-dynamic-extensions";
+
+/** @type {(require: NodeJS.Require) => Plugin<Hooks>} */
+exports.factory = (require) => {
+  const { Project, SettingsType, structUtils } = require("@yarnpkg/core");
+  const { npath } = require("@yarnpkg/fslib");
+
+  /**
+   * @param {Configuration} configuration
+   * @param {PortablePath} projectRoot
+   * @returns {Promise<((ws: Workspace) => PackageExtensionData | undefined) | void>}
+   */
+  async function loadUserExtensions(configuration, projectRoot) {
+    const packageExtensions = configuration.get(DYNAMIC_PACKAGE_EXTENSIONS_KEY);
+    if (typeof packageExtensions !== "string") {
+      return;
+    }
+
+    const path = require("node:path");
+    const { pathToFileURL } = require("node:url");
+
+    // Make sure we resolve user extensions relative to the source config
+    const source = configuration.sources.get(DYNAMIC_PACKAGE_EXTENSIONS_KEY);
+    const sourceDir = source ? npath.dirname(source) : projectRoot;
+
+    // On Windows, import paths must include the `file:` protocol.
+    const root = npath.fromPortablePath(sourceDir);
+    const url = pathToFileURL(path.resolve(root, packageExtensions));
+    const external = await import(url.toString());
+    return external?.default ?? external;
+  }
+
+  /** @type {Plugin<Hooks>["configuration"] & Record<string, unknown>} */
+  const configuration = {};
+  configuration[DYNAMIC_PACKAGE_EXTENSIONS_KEY] = {
+    description: "Path to module providing package extensions",
+    type: SettingsType.STRING,
+  };
+
+  return {
+    configuration,
+    hooks: {
+      registerPackageExtensions: async (
+        configuration,
+        registerPackageExtension
+      ) => {
+        const { projectCwd } = configuration;
+        if (!projectCwd) {
+          return;
+        }
+
+        const getUserExtensions = await loadUserExtensions(
+          configuration,
+          projectCwd
+        );
+        if (!getUserExtensions) {
+          return;
+        }
+
+        const { workspace } = await Project.find(configuration, projectCwd);
+        if (!workspace) {
+          return;
+        }
+
+        workspace.project.workspacesByCwd.forEach(({ cwd, manifest }) => {
+          const { name, version, raw } = manifest;
+          if (!name || !version) {
+            return;
+          }
+
+          /** @type {Workspace} */
+          const workspace = { cwd: npath.fromPortablePath(cwd), manifest: raw };
+          const data = getUserExtensions(workspace);
+          if (!data) {
+            return;
+          }
+
+          const descriptor = structUtils.makeDescriptor(name, version);
+          registerPackageExtension(descriptor, data);
+        });
+      },
+    },
+  };
+};

.yarnrc.yml

@@ -1,5 +1,12 @@
+dynamicPackageExtensions: ./scripts/dynamic.extensions.mjs
+
 enableGlobalCache: false
 
 nodeLinker: node-modules
 
-yarnPath: .yarn/releases/yarn-4.6.0.cjs
+plugins:
+  - checksum: 672e525b81762c6162366bd3ffec5e86ab8fac2655ef0267047e86a0f32e79a4bde0f170bc30479663f40aa3f006d91f8dc3289f679dd4dc5ae5a5d12ba3ad0b
+    path: .yarn/plugins/@rnx-kit/yarn-plugin-dynamic-extensions.cjs
+    spec: "https://raw.githubusercontent.com/microsoft/rnx-kit/main/incubator/yarn-plugin-dynamic-extensions/index.js"
+
+yarnPath: .yarn/releases/yarn-4.9.2.cjs

package.json

@@ -100,5 +100,5 @@
       ]
     }
   },
-  "packageManager": "yarn@4.6.0"
+  "packageManager": "yarn@4.9.2"
 }

scripts/dynamic.extensions.mjs

@@ -0,0 +1,46 @@
+import fs from 'fs';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+/**
+ * @param {Object} workspace           The package currently being processed
+ * @param {string} workspace.cwd       Path of the current package
+ * @param {Object} workspace.manifest  The content of `package.json`
+ * @returns {{
+ *   dependencies?: Record<string, string>;
+ *   peerDependencies?: Record<string, string>;
+ *   peerDependenciesMeta?: Record<string, { optional?: boolean }>;
+ * }}
+ */
+
+/**
+ * These are the dependencies we want to ensure exist in each folder. They will not override
+ * the dependencies in the package.json if already present.
+ */
+const scriptDependencies = getScriptFolderDependencies(['typescript', 'eslint', 'just-scripts']);
+
+/**
+ * Get the dependencies for the script folder, both `devDependencies` and `dependencies`
+ * @param {string[]} keys - The keys of the dependencies to include
+ * @returns {Record<string, string>} A map of dependencies for the script folder
+ */
+function getScriptFolderDependencies(keys) {
+  const pkgJsonName = path.join(path.dirname(fileURLToPath(import.meta.url)), './package.json');
+  const pkgJson = JSON.parse(fs.readFileSync(pkgJsonName, 'utf-8'));
+  const mergedDeps = { ...pkgJson.devDependencies, ...pkgJson.dependencies };
+  return Object.fromEntries(Object.entries(mergedDeps).filter(([key]) => keys.includes(key)));
+}
+
+export default function ({ cwd, manifest }) {
+  const dependenciesToAdd = {};
+  Object.keys(scriptDependencies).forEach((key) => {
+    if ((manifest?.dependencies && manifest.dependencies[key]) || (manifest?.devDependencies && manifest.devDependencies[key])) {
+      // If the dependency already exists in the package.json, skip it
+      return;
+    }
+    dependenciesToAdd[key] = scriptDependencies[key];
+  });
+  return {
+    dependencies: dependenciesToAdd,
+  };
+}

tester_deps/.yarnrc.yml

@@ -1 +1 @@
-yarnPath: ../.yarn/releases/yarn-4.6.0.cjs
+yarnPath: ../.yarn/releases/yarn-4.9.2.cjs