perf(module-concat): cache incoming analysis across roots

Cache runtime-dependent incoming module analysis across root searches while keeping root-specific chunk and ESM checks outside the cache. Add runtime-isolation coverage for multi-runtime builds.

Co-authored-by: ScriptedAlchemy <zackary.l.jackson@gmail.com>

Author: LingyuCoder

crates/rspack_plugin_javascript/src/plugin/module_concatenation_plugin.rs

@@ -0,0 +1,21 @@
+import { getValue as getRootAValue } from "./root-a";
+import { stable } from "./root-shared";
+
+it("should keep runtime-specific concatenation results isolated", () => {
+  expect(getRootAValue()).toBe(42);
+  expect(stable).toBe(1);
+
+  const rootAGroup = __STATS__.modules.find(module =>
+    module.modules?.some(nested => nested.name.endsWith("root-a.js"))
+  );
+  expect(rootAGroup).toBeDefined();
+
+  const shared = __STATS__.modules.find(module => module.name.endsWith("root-shared.js"));
+  expect(shared).toBeDefined();
+  const expectedBailout = globalThis.__RSPACK_TEST_RUNTIME_MODE_RSPACK
+    ? "runtime-dependent referenced"
+    : "not in the same chunk(s)";
+  expect(shared.optimizationBailout).toEqual(
+    expect.arrayContaining([expect.stringContaining(expectedBailout)])
+  );
+});

tests/rspack-test/configCases/concatenate-modules/runtime-cache-isolation/a.js

@@ -0,0 +1,5 @@
+import { getValue } from "./root-shared";
+
+it("should preserve the runtime-dependent export", () => {
+  expect(getValue()).toBe(42);
+});

tests/rspack-test/configCases/concatenate-modules/runtime-cache-isolation/b.js

@@ -0,0 +1 @@
+export let value = 42;

tests/rspack-test/configCases/concatenate-modules/runtime-cache-isolation/leaf.js

@@ -0,0 +1,3 @@
+import { value } from "./leaf";
+
+export const getValue = () => value;

tests/rspack-test/configCases/concatenate-modules/runtime-cache-isolation/root-a.js

@@ -0,0 +1,4 @@
+import { value } from "./leaf";
+
+export const stable = 1;
+export const getValue = () => value;

tests/rspack-test/configCases/concatenate-modules/runtime-cache-isolation/root-shared.js

@@ -0,0 +1,42 @@
+/** @type {import("@rspack/core").Configuration} */
+module.exports = {
+  mode: 'production',
+  entry: {
+    a: './a.js',
+    b: './b.js',
+  },
+  output: {
+    filename: '[name].js',
+  },
+  module: {
+    rules: [
+      {
+        test: /\.js$/,
+        sideEffects: false,
+      },
+    ],
+  },
+  optimization: {
+    concatenateModules: true,
+    innerGraph: true,
+    minimize: false,
+    sideEffects: true,
+    splitChunks: {
+      chunks: 'all',
+      minSize: 0,
+      cacheGroups: {
+        shared: {
+          enforce: true,
+          name: 'shared',
+          test: /root-shared/,
+        },
+      },
+    },
+    usedExports: true,
+  },
+  stats: {
+    modules: true,
+    nestedModules: true,
+    optimizationBailout: true,
+  },
+};

tests/rspack-test/configCases/concatenate-modules/runtime-cache-isolation/rspack.config.js

@@ -0,0 +1,5 @@
+module.exports = {
+  findBundle() {
+    return ["shared.js", "a.js", "b.js"];
+  },
+};