Fix memory leak in `fetch(url)` (#2989)

* Fix memory leak in `fetch(url)`

* Bump those numbers up

---------

Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>

1 files changed, 34 insertions, 0 deletions

diff --git a/test/js/web/fetch/fetch-leak-test-fixture.js b/test/js/web/fetch/fetch-leak-test-fixture.js
new file mode 100644
index 000000000..07275a425
--- /dev/null
+++ b/test/js/web/fetch/fetch-leak-test-fixture.js
@@ -0,0 +1,34 @@
+import { heapStats } from "bun:jsc";
+
+const { SERVER } = process.env;
+
+if (typeof SERVER === "undefined" || !SERVER?.length) {
+  throw new Error("SERVER environment variable is not set");
+}
+
+const COUNT = parseInt(process.env.COUNT || "50", 10);
+await (async function runAll() {
+  var fetches = new Array(COUNT);
+  let i = 0;
+  while (i < Math.max(COUNT - 32, 0)) {
+    for (let j = 0; j < 32; j++) {
+      fetches.push(fetch(SERVER));
+    }
+    await Promise.all(fetches.slice(i, i + 32));
+    i += 32;
+  }
+
+  while (i++ < COUNT) {
+    fetches.push(fetch(SERVER));
+  }
+
+  await Promise.all(fetches);
+  fetches.length = 0;
+  fetches = [];
+})();
+await Bun.sleep(10);
+Bun.gc(true);
+
+if ((heapStats().objectTypeCounts.Response ?? 0) > 10) {
+  throw new Error("Too many Response objects: " + heapStats().objectTypeCounts.Response);
+}