feat(monorepo): align pdk projen peer dep version with synthesized pr…

…ojects projen version

This change ensures all subprojects of a monorepo have the same projen version as the monorepo
itself for non-runtime dependencies, and sets the default projen version to 0.79.x. This also
provides a single place to change when updating the peer dependency version of projen for PDK, which
will automatically ensure vended PDK projects have that same version and we avoid the "unmet peer"
warning in future.

Fixes #661

packages/monorepo/src/components/projen-dependency.ts

@@ -0,0 +1,29 @@
+/*! Copyright [Amazon.com](http://amazon.com/), Inc. or its affiliates. All Rights Reserved.
+SPDX-License-Identifier: Apache-2.0 */
+import { DependencyType, Project } from "projen";
+import PROJEN_VERSION from "./projen-version";
+
+export const DEFAULT_PROJEN_VERSION = PROJEN_VERSION;
+
+/**
+ * Synchronise all subproject projen versions to the given projen version
+ */
+export const syncProjenVersions = (
+  subProjects: Project[],
+  projenVersion: string = DEFAULT_PROJEN_VERSION
+) => {
+  subProjects.forEach((subProject) => {
+    // Set the projen version to one consistent with the monorepo for any node projects
+    const projenDependencies = subProject.deps.all.filter(
+      (d) => d.name === "projen" && d.type !== DependencyType.RUNTIME
+    );
+    projenDependencies.forEach((d) => {
+      subProject.deps.removeDependency(d.name, d.type);
+      subProject.deps.addDependency(
+        `projen@${projenVersion}`,
+        d.type,
+        d.metadata
+      );
+    });
+  });
+};

packages/monorepo/src/components/projen-version.ts

@@ -0,0 +1 @@
+export default "^0.79.6";

packages/monorepo/src/projects/java/monorepo-java.ts

@@ -11,6 +11,10 @@ import {
   INxProjectCore,
 } from "../../components/nx-configurator";
 import { NxWorkspace } from "../../components/nx-workspace";
+import {
+  DEFAULT_PROJEN_VERSION,
+  syncProjenVersions,
+} from "../../components/projen-dependency";
 import { Nx } from "../../nx-types";
 
 const MVN_PLUGIN_PATH = "./.nx/plugins/nx_plugin.js";
@@ -32,6 +36,11 @@ export class MonorepoJavaProject extends JavaProject implements INxProjectCore {
   public readonly nxConfigurator: NxConfigurator;
   private readonly installTask: Task;
 
+  /**
+   * Version of projen used by the monorepo and its subprojects
+   */
+  private readonly projenVersion: string;
+
   constructor(options: MonorepoJavaOptions) {
     super({
       ...options,
@@ -40,7 +49,14 @@ export class MonorepoJavaProject extends JavaProject implements INxProjectCore {
       version: options.version ?? "0.0.0",
       groupId: options.groupId ?? "com.aws",
       artifactId: options.artifactId ?? "monorepo",
+      projenrcJavaOptions: {
+        ...options.projenrcJavaOptions,
+        projenVersion:
+          options.projenrcJavaOptions?.projenVersion ?? DEFAULT_PROJEN_VERSION,
+      },
     });
+    this.projenVersion =
+      options.projenrcJavaOptions?.projenVersion ?? DEFAULT_PROJEN_VERSION;
 
     this.addTestDependency("software.aws/pdk@^0");
 
@@ -155,6 +171,8 @@ export class MonorepoJavaProject extends JavaProject implements INxProjectCore {
     this.nxConfigurator.preSynthesize();
 
     super.preSynthesize();
+
+    syncProjenVersions(this.subprojects, this.projenVersion);
   }
 
   /**