From 571e6201695a1b3a5b01c007d1d875adddeecb9b Mon Sep 17 00:00:00 2001
From: greymoth-jp <m.hirakawa07@icloud.com>
Date: Mon, 29 Jun 2026 08:57:16 +0900
Subject: [PATCH] fix(webpack): forward async load hook errors to the loader
 callback

---
 src/webpack/loaders/load.ts                  | 44 ++++++++++++--------
 test/unit-tests/webpack/loaders/load.test.ts | 13 ++++++
 2 files changed, 40 insertions(+), 17 deletions(-)

diff --git a/src/webpack/loaders/load.ts b/src/webpack/loaders/load.ts
index e2fd10fa..4b2f03a6 100644
--- a/src/webpack/loaders/load.ts
+++ b/src/webpack/loaders/load.ts
@@ -17,22 +17,32 @@ export default async function load(this: LoaderContext<any>, source: string, map
 
   const context = createContext(this)
   const { handler } = normalizeObjectHook('load', plugin.load)
-  const res = await handler.call(
-    Object.assign({}, createBuildContext({
-      addWatchFile: (file) => {
-        this.addDependency(file)
-      },
-      getWatchFiles: () => {
-        return this.getDependencies()
-      },
-    }, this._compiler!, this._compilation, this), context),
-    normalizeAbsolutePath(id),
-  )
+  try {
+    const res = await handler.call(
+      Object.assign({}, createBuildContext({
+        addWatchFile: (file) => {
+          this.addDependency(file)
+        },
+        getWatchFiles: () => {
+          return this.getDependencies()
+        },
+      }, this._compiler!, this._compilation, this), context),
+      normalizeAbsolutePath(id),
+    )
 
-  if (res == null)
-    callback(null, source, map)
-  else if (typeof res !== 'string')
-    callback(null, res.code, res.map ?? map)
-  else
-    callback(null, res, map)
+    if (res == null)
+      callback(null, source, map)
+    else if (typeof res !== 'string')
+      callback(null, res.code, res.map ?? map)
+    else
+      callback(null, res, map)
+  }
+  catch (error) {
+    if (error instanceof Error) {
+      callback(error)
+    }
+    else {
+      callback(new Error(String(error)))
+    }
+  }
 }
diff --git a/test/unit-tests/webpack/loaders/load.test.ts b/test/unit-tests/webpack/loaders/load.test.ts
index f8f182ed..9dd35d4a 100644
--- a/test/unit-tests/webpack/loaders/load.test.ts
+++ b/test/unit-tests/webpack/loaders/load.test.ts
@@ -62,4 +62,17 @@ describe('load function', () => {
 
     expect(mockCallback).toHaveBeenCalledWith(null, transformedCode, map)
   })
+
+  it('should call callback with the error if the handler throws', async () => {
+    const source = 'source code'
+    const map = 'source map'
+    const error = new Error('Handler error')
+    const pluginLoadHandler = vi.fn().mockRejectedValue(error)
+    mockLoaderContext.query.plugin.load = pluginLoadHandler
+
+    await load.call(mockLoaderContext as any, source, map)
+
+    expect(pluginLoadHandler).toHaveBeenCalled()
+    expect(mockCallback).toHaveBeenCalledWith(error)
+  })
 })