From 5395d95fbcaa40088c1b546ccbbbbdcead76a289 Mon Sep 17 00:00:00 2001
From: Jakub Romanczyk <jakub.romanczyk@callstack.com>
Date: Wed, 5 Feb 2025 18:35:56 +0100
Subject: [PATCH 1/2] fix: avoid falsy values or plugin functions in
 checkSingleton

---
 packages/rspack/src/ModuleFederationPlugin.ts | 26 ++++++++++++-------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/packages/rspack/src/ModuleFederationPlugin.ts b/packages/rspack/src/ModuleFederationPlugin.ts
index 5142f895661..82c9bca7e38 100644
--- a/packages/rspack/src/ModuleFederationPlugin.ts
+++ b/packages/rspack/src/ModuleFederationPlugin.ts
@@ -1,6 +1,8 @@
 import type {
   Compiler,
+  Falsy,
   ModuleFederationPluginOptions,
+  RspackPluginFunction,
   RspackPluginInstance,
 } from '@rspack/core';
 import {
@@ -48,16 +50,22 @@ export class ModuleFederationPlugin implements RspackPluginInstance {
 
   private _checkSingleton(compiler: Compiler): void {
     let count = 0;
-    compiler.options.plugins.forEach((p: any) => {
-      if (p.name === this.name) {
-        count++;
-        if (count > 1) {
-          throw new Error(
-            `Detect duplicate register ${this.name},please ensure ${this.name} is singleton!`,
-          );
+    compiler.options.plugins.forEach(
+      (p: Falsy | RspackPluginInstance | RspackPluginFunction) => {
+        if (typeof p !== 'object' || !p) {
+          return;
         }
-      }
-    });
+
+        if (p['name'] === this.name) {
+          count++;
+          if (count > 1) {
+            throw new Error(
+              `Detect duplicate register ${this.name},please ensure ${this.name} is singleton!`,
+            );
+          }
+        }
+      },
+    );
   }
 
   apply(compiler: Compiler): void {

From 991d333bae9b84ce485a67e3a9a7da1391163a82 Mon Sep 17 00:00:00 2001
From: Jakub Romanczyk <jakub.romanczyk@callstack.com>
Date: Wed, 5 Feb 2025 18:45:47 +0100
Subject: [PATCH 2/2] chore: add changeset

---
 .changeset/red-ads-flow.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/red-ads-flow.md

diff --git a/.changeset/red-ads-flow.md b/.changeset/red-ads-flow.md
new file mode 100644
index 00000000000..2d41e6d5140
--- /dev/null
+++ b/.changeset/red-ads-flow.md
@@ -0,0 +1,5 @@
+---
+'@module-federation/rspack': patch
+---
+
+Check for falsy values when looking for duplicate ModuleFederationPlugin entries