feat(enhanced): compose the runtime bootstrap behind experiments.composedRuntime

.changeset/composed-runtime-enhanced.md

@@ -0,0 +1,6 @@
+---
+'@module-federation/enhanced': minor
+'@module-federation/sdk': minor
+---
+
+Add `experiments.composedRuntime` to `ModuleFederationPlugin`. When the installed runtime exports its capability subpaths, the plugin generates a federation bootstrap that imports only the runtime parts the build uses, and checks the module graph for federation modules whose adapter is missing. Builds without the flag are unchanged.

packages/enhanced/src/lib/container/ContainerPlugin.ts

@@ -16,6 +16,9 @@ import type {
 } from 'webpack';
 import type { containerPlugin } from '@module-federation/sdk';
 import FederationRuntimePlugin from './runtime/FederationRuntimePlugin';
+import FederationCompositionPlugin, {
+  type CoveredByOptions,
+} from './runtime/FederationCompositionPlugin';
 import FederationModulesPlugin from './runtime/FederationModulesPlugin';
 import FederationRuntimeDependency from './runtime/FederationRuntimeDependency';
 import type { OptimizationSplitChunksCacheGroup } from 'webpack/lib/optimize/SplitChunksPlugin';
@@ -34,8 +37,13 @@ const PLUGIN_NAME = 'ContainerPlugin';
 class ContainerPlugin {
   _options: containerPlugin.ContainerPluginOptions;
   name: string;
+  private _covered?: CoveredByOptions;
 
-  constructor(options: containerPlugin.ContainerPluginOptions) {
+  constructor(
+    options: containerPlugin.ContainerPluginOptions,
+    covered?: CoveredByOptions,
+  ) {
+    this._covered = covered;
     // validate(options);
     this.name = PLUGIN_NAME;
 
@@ -164,6 +172,12 @@ class ContainerPlugin {
       ContainerPlugin.patchChunkSplit(compiler, this._options.name);
     }
 
+    if (!this._covered) {
+      FederationCompositionPlugin.register(compiler, {
+        kind: 'needs',
+        needs: ['container'],
+      });
+    }
     const federationRuntimePluginInstance = new FederationRuntimePlugin();
     federationRuntimePluginInstance.apply(compiler);
 

packages/enhanced/src/lib/container/ContainerReferencePlugin.ts

@@ -18,6 +18,9 @@ import type {
   moduleFederationPlugin,
 } from '@module-federation/sdk';
 import FederationRuntimePlugin from './runtime/FederationRuntimePlugin';
+import FederationCompositionPlugin, {
+  type CoveredByOptions,
+} from './runtime/FederationCompositionPlugin';
 import FederationModulesPlugin from './runtime/FederationModulesPlugin';
 
 const { ExternalsPlugin } = require(
@@ -30,9 +33,13 @@ class ContainerReferencePlugin {
   private _remoteType: moduleFederationPlugin.ExternalsType;
   private _remotes: [string, moduleFederationPlugin.RemotesConfig][];
 
+  private _covered?: CoveredByOptions;
+
   constructor(
     options: containerReferencePlugin.ContainerReferencePluginOptions,
+    covered?: CoveredByOptions,
   ) {
+    this._covered = covered;
     // validate(options);
 
     this._remoteType = options.remoteType;
@@ -58,6 +65,12 @@ class ContainerReferencePlugin {
    */
   apply(compiler: Compiler): void {
     const { _remotes: remotes, _remoteType: remoteType } = this;
+    if (!this._covered) {
+      FederationCompositionPlugin.register(compiler, {
+        kind: 'needs',
+        needs: ['remotes'],
+      });
+    }
     new FederationRuntimePlugin().apply(compiler);
     /** @type {Record<string, string>} */
     const remoteExternals: Record<string, string> = {};

packages/enhanced/src/lib/container/ModuleFederationPlugin.ts

@@ -21,6 +21,11 @@ import SharePlugin from '../sharing/SharePlugin';
 import ContainerPlugin from './ContainerPlugin';
 import ContainerReferencePlugin from './ContainerReferencePlugin';
 import FederationRuntimePlugin from './runtime/FederationRuntimePlugin';
+import FederationCompositionPlugin, {
+  COVERED_BY_OPTIONS,
+  composedEntryOf,
+  optionsParticipant,
+} from './runtime/FederationCompositionPlugin';
 import { RemoteEntryPlugin } from '@module-federation/rspack/remote-entry-plugin';
 import StartupChunkDependenciesPlugin from '../startup/MfStartupChunkDependenciesPlugin';
 import FederationModulesPlugin from './runtime/FederationModulesPlugin';
@@ -155,6 +160,16 @@ class ModuleFederationPlugin implements WebpackPluginInstance {
     // No inference for ENV_TARGET. If not manually set and valid, it's not defined.
 
     new compiler.webpack.DefinePlugin(definePluginOptions).apply(compiler);
+
+    if (experiments?.composedRuntime) {
+      // DefinePlugin reads its definitions per compilation, after the plan picked a mode.
+      compiler.hooks.compile.tap('ModuleFederationPlugin', () => {
+        if (!composedEntryOf(compiler)) return;
+        for (const key of Object.keys(definePluginOptions)) {
+          if (key !== 'ENV_TARGET') delete definePluginOptions[key];
+        }
+      });
+    }
   }
 
   /**
@@ -200,6 +215,7 @@ class ModuleFederationPlugin implements WebpackPluginInstance {
 
     // federation hooks
     new FederationModulesPlugin().apply(compiler);
+    FederationCompositionPlugin.register(compiler, optionsParticipant(options));
 
     if (experiments?.asyncStartup) {
       new StartupChunkDependenciesPlugin({
@@ -251,36 +267,45 @@ class ModuleFederationPlugin implements WebpackPluginInstance {
 
     compiler.hooks.afterPlugins.tap('ModuleFederationPlugin', () => {
       if (useContainerPlugin) {
-        new ContainerPlugin({
-          name,
-          library,
-          filename: options.filename,
-          runtime: options.runtime,
-          shareScope: options.shareScope,
-          exposes: options.exposes!,
-          runtimePlugins: options.runtimePlugins,
-        }).apply(compiler);
+        new ContainerPlugin(
+          {
+            name,
+            library,
+            filename: options.filename,
+            runtime: options.runtime,
+            shareScope: options.shareScope,
+            exposes: options.exposes!,
+            runtimePlugins: options.runtimePlugins,
+          },
+          COVERED_BY_OPTIONS,
+        ).apply(compiler);
       }
       if (
         remotes &&
         (Array.isArray(remotes)
           ? remotes.length > 0
           : Object.keys(remotes).length > 0)
       ) {
-        new ContainerReferencePlugin({
-          remoteType: containerRemoteType,
-          shareScope,
-          remotes,
-        }).apply(compiler);
+        new ContainerReferencePlugin(
+          {
+            remoteType: containerRemoteType,
+            shareScope,
+            remotes,
+          },
+          COVERED_BY_OPTIONS,
+        ).apply(compiler);
       }
       if (shared) {
         new TreeShakingSharedPlugin({
           mfConfig: options,
         }).apply(compiler);
-        new SharePlugin({
-          shared,
-          shareScope,
-        }).apply(compiler);
+        new SharePlugin(
+          {
+            shared,
+            shareScope,
+          },
+          COVERED_BY_OPTIONS,
+        ).apply(compiler);
       }
     });