5 files changed, 99 insertions, 3 deletions

diff --git a/bench/fetch/bun.js b/bench/fetch/bun.js
new file mode 100644
index 000000000..f61eeb0c6
--- /dev/null
+++ b/bench/fetch/bun.js
@@ -0,0 +1,17 @@
+import { bench, run } from "mitata";
+
+const count = 100;
+
+bench(`fetch(https://example.com) x ${count}`, async () => {
+  const requests = new Array(count);
+
+  for (let i = 0; i < requests.length; i++) {
+    requests[i] = fetch(`https://www.example.com/?cachebust=${i}`).then((r) =>
+      r.text()
+    );
+  }
+
+  await Promise.all(requests);
+});
+
+await run();
diff --git a/bench/fetch/deno.js b/bench/fetch/deno.js
new file mode 100644
index 000000000..929a478a0
--- /dev/null
+++ b/bench/fetch/deno.js
@@ -0,0 +1,17 @@
+import { bench, run } from "https://esm.run/mitata";
+
+const count = 100;
+
+bench(`fetch(https://example.com) x ${count}`, async () => {
+  const requests = new Array(count);
+
+  for (let i = 0; i < requests.length; i++) {
+    requests[i] = fetch(`https://www.example.com/?cachebust=${i}`).then((r) =>
+      r.text()
+    );
+  }
+
+  await Promise.all(requests);
+});
+
+await run();
diff --git a/bench/fetch/node.mjs b/bench/fetch/node.mjs
new file mode 100644
index 000000000..f61eeb0c6
--- /dev/null
+++ b/bench/fetch/node.mjs
@@ -0,0 +1,17 @@
+import { bench, run } from "mitata";
+
+const count = 100;
+
+bench(`fetch(https://example.com) x ${count}`, async () => {
+  const requests = new Array(count);
+
+  for (let i = 0; i < requests.length; i++) {
+    requests[i] = fetch(`https://www.example.com/?cachebust=${i}`).then((r) =>
+      r.text()
+    );
+  }
+
+  await Promise.all(requests);
+});
+
+await run();
diff --git a/src/bun.js/api/server.zig b/src/bun.js/api/server.zig
index 0cb5d4cd1..0adaf8b3b 100644
--- a/src/bun.js/api/server.zig
+++ b/src/bun.js/api/server.zig
@@ -3644,13 +3644,11 @@ pub fn NewServer(comptime ssl_enabled_: bool, comptime debug_mode_: bool) type {
             if (upgrader.aborted) {
                 return JSC.jsBoolean(false);
             }
-            request.upgrader = null;
+
             if (upgrader.upgrade_context == null or @ptrToInt(upgrader.upgrade_context) == std.math.maxInt(usize)) {
                 return JSC.jsBoolean(false);
             }
             var ctx = upgrader.upgrade_context.?;
-            // obviously invalid pointer marks it as used
-            upgrader.upgrade_context = @intToPtr(*uws.uws_socket_context_s, std.math.maxInt(usize));
 
             var sec_websocket_key_str = ZigString.Empty;
 
@@ -3736,6 +3734,13 @@ pub fn NewServer(comptime ssl_enabled_: bool, comptime debug_mode_: bool) type {
                 }
             }
 
+            // --- After this point, do not throw an exception
+            // See https://github.com/oven-sh/bun/issues/1339
+
+            // obviously invalid pointer marks it as used
+            upgrader.upgrade_context = @intToPtr(*uws.uws_socket_context_s, std.math.maxInt(usize));
+            request.upgrader = null;
+
             upgrader.resp.clearAborted();
             var ws = this.vm.allocator.create(ServerWebSocket) catch return .zero;
             ws.* = .{
diff --git a/test/bun.js/websocket-server.test.ts b/test/bun.js/websocket-server.test.ts
index 61cd08f7a..6c2dfa64f 100644
--- a/test/bun.js/websocket-server.test.ts
+++ b/test/bun.js/websocket-server.test.ts
@@ -53,6 +53,46 @@ describe("websocket server", () => {
     });
     server.stop();
   });
+
+  it("headers error doesn't crash", async () => {
+    var resolve, reject;
+    var server = serve({
+      port: getPort(),
+      websocket: {
+        open(ws) {},
+        message(ws, msg) {},
+        close() {
+          resolve();
+        },
+      },
+      error(err) {
+        resolve();
+      },
+      fetch(req, server) {
+        if (
+          server.upgrade(req, {
+            data: "hello world",
+
+            headers: 1238,
+          })
+        ) {
+          reject();
+          return;
+        }
+        reject();
+        return new Response("noooooo hello world");
+      },
+    });
+
+    await new Promise((resolve_, reject) => {
+      resolve = resolve_;
+      const websocket = new WebSocket(`ws://localhost:${server.port}`);
+      websocket.onopen = () => websocket.close();
+      websocket.onmessage = (e) => {};
+      websocket.onerror = (e) => {};
+    });
+    server.stop();
+  });
   it("can do hello world", async () => {
     var server = serve({
       port: getPort(),