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);
+        });
+      },
+    },
+  };
+};