Test if it leaks when the given signal never aborts and connection succeeds

.changeset/seven-forks-tease.md

@@ -0,0 +1,11 @@
+---
+'@whatwg-node/node-fetch': patch
+---
+
+Remove the event listener on the provided `AbortSignal` when `node-libcurl` is used, the connection finishes to prevent
+potential memory leaks;
+
+```ts
+const res = await fetch(URL, { signal: new AbortController().signal });
+// AbortController is never aborted, and HTTP request is done as expected successfully
+```

packages/node-fetch/src/fetchCurl.ts

@@ -83,23 +83,27 @@ export function fetchCurl<TResponseJSON = any, TRequestJSON = any>(
 
   const deferredPromise = createDeferredPromise<PonyfillResponse<TResponseJSON>>();
   let streamResolved: Readable | undefined;
-  if (fetchRequest['_signal']) {
-    fetchRequest['_signal'].onabort = () => {
-      if (curlHandle.isOpen) {
-        try {
-          curlHandle.pause(CurlPause.Recv);
-        } catch (e) {
-          deferredPromise.reject(e);
-        }
+  function onAbort() {
+    if (curlHandle.isOpen) {
+      try {
+        curlHandle.pause(CurlPause.Recv);
+      } catch (e) {
+        deferredPromise.reject(e);
       }
-    };
+    }
+  }
+  if (fetchRequest['_signal']) {
+    fetchRequest['_signal'].addEventListener('abort', onAbort, { once: true });
   }
   curlHandle.once('end', function endListener() {
     try {
       curlHandle.close();
     } catch (e) {
       deferredPromise.reject(e);
     }
+    if (fetchRequest['_signal']) {
+      fetchRequest['_signal'].removeEventListener('abort', onAbort);
+    }
   });
   curlHandle.once('error', function errorListener(error: any) {
     if (streamResolved && !streamResolved.closed && !streamResolved.destroyed) {

packages/node-fetch/tests/fetch.spec.ts

@@ -254,6 +254,14 @@ describe('Node Fetch Ponyfill', () => {
         expect(response.status).toBe(200);
         expect(response.url === 'https://github.com' || response.redirected).toBeTruthy();
       });
+      it('does not leak when signal is not used', async () => {
+        const res = await fetchPonyfill(baseUrl, { signal: new AbortController().signal });
+        await res.text();
+      });
+      it('does not leak when timeout signal is not used', async () => {
+        const res = await fetchPonyfill(baseUrl, { signal: AbortSignal.timeout(10_000) });
+        await res.text();
+      });
     },
   );
 });

yarn.lock

@@ -319,7 +319,7 @@
   dependencies:
     "@babel/helper-plugin-utils" "^7.25.9"
 
-"@babel/plugin-syntax-import-meta@7.10.4", "@babel/plugin-syntax-import-meta@^7.10.4":
+"@babel/plugin-syntax-import-meta@^7.10.4":
   version "7.10.4"
   resolved "https://registry.yarnpkg.com/@babel/plugin-syntax-import-meta/-/plugin-syntax-import-meta-7.10.4.tgz#ee601348c370fa334d2207be158777496521fd51"
   integrity sha512-Yqfm+XDx0+Prh3VSeEQCPU81yC+JWZ2pDPFSS4ZdpfZhp4MkFMaDC1UqseovEKwSUpnIL7+vK+Clp7bfh0iD7g==