fix(side-effects): respect DefinePlugin purity evaluation (#13628)

Author: ahabhgk

crates/rspack_plugin_javascript/src/parser_plugin/side_effects_parser_plugin.rs

@@ -1661,12 +1661,19 @@ pub fn is_pure_expression<'a>(
         }
         true
       }
-      _ => !expr.may_have_side_effects(ExprCtx {
-        unresolved_ctxt,
-        is_unresolved_ref_safe: true,
-        in_strict: false,
-        remaining_depth: 4,
-      }),
+      _ => {
+        if !expr.may_have_side_effects(ExprCtx {
+          unresolved_ctxt,
+          is_unresolved_ref_safe: true,
+          in_strict: false,
+          remaining_depth: 4,
+        }) {
+          return true;
+        }
+        // could_have_side_effects is true by default, so here we test if it's modified by other plugins to return false.
+        let evaluated = parser.evaluate_expression(expr);
+        !evaluated.could_have_side_effects()
+      }
     }
   }
   _is_pure_expression(

tests/rspack-test/configCases/side-effects/define-plugin/index.js

@@ -0,0 +1,10 @@
+import { f } from "./reexport";
+
+it("should not include reexport modules", async () => {
+	const content = await __non_webpack_require__("fs/promises").readFile(__filename, "utf-8");
+	expect(f()).toBe(42);
+	const sideEffectsFreeModules = ["./lib/index" + ".js", "./reexport" + ".js"];
+	for (const module of sideEffectsFreeModules) {
+		expect(content).not.toContain(module);
+	}
+});

tests/rspack-test/configCases/side-effects/define-plugin/lib/index.js

@@ -0,0 +1,7 @@
+export * from "./module";
+
+const createApp = () => {
+    console.log("__CREATE_APP__");
+}
+
+export { createApp };

tests/rspack-test/configCases/side-effects/define-plugin/lib/module.js

@@ -0,0 +1,3 @@
+export function f() {
+	return 42;
+}

tests/rspack-test/configCases/side-effects/define-plugin/lib/package.json

@@ -0,0 +1,3 @@
+{
+    "sideEffects": false
+}

tests/rspack-test/configCases/side-effects/define-plugin/reexport.js

@@ -0,0 +1,5 @@
+export * from "./lib/index";
+
+if (!!(process.env.NODE_ENV !== "production")) {
+    console.log("This is a side effect");
+}

tests/rspack-test/configCases/side-effects/define-plugin/rspack.config.js

@@ -0,0 +1,15 @@
+const { rspack } = require('@rspack/core');
+
+/** @type {import("@rspack/core").Configuration} */
+module.exports = {
+  optimization: {
+    sideEffects: true,
+    moduleIds: 'named',
+    concatenateModules: false,
+  },
+  plugins: [
+    new rspack.DefinePlugin({
+      'process.env.NODE_ENV': JSON.stringify('production'),
+    }),
+  ],
+};