node:net: honor pause() made inside the 'connection' handler

src/js/node/net.ts

@@ -881,9 +881,11 @@
     // after secureConnection event we emmit secure and secureConnect
     self.emit("secure", self);
     self.emit("secureConnect", verifyError);
     if (server?.pauseOnConnect) {
       self.pause();
-    } else {
+    } else if (self.readableFlowing === null) {
+      // See onconnection: honor a pause()/'data'/'readable' touched inside
+      // the secureConnection/secureConnect handlers.
       self.resume();
     }
   },
@@ -1063,8 +1065,11 @@
   }
 
   self.emit("connection", _socket);
-  // the duplex implementation start paused, so we resume when pauseOnConnect is falsy
-  if (!pauseOnConnect && !isTLS) {
+  // Honor a pause()/'data'/'readable' touched inside the handler. null (the
+  // handler left flowing untouched) still resumes so a write-only handler's
+  // peer-close tears down; Node would leave it null and release the loop via
+  // UV_EOF readStop, which needs accepted sockets to hold the loop themselves.
+  if (!pauseOnConnect && !isTLS && _socket.readableFlowing === null) {
     _socket.resume();
   }
 }

test/js/node/net/node-net.test.ts

@@ -1132,3 +1132,24 @@ it.skipIf(isWindows)("connect({ localPort }) succeeds when the local port has TI
     target.close();
   }
 });
+
+// onconnection / ServerHandlers.handshake previously resume()d after emit,
+// stomping a pause() made inside the handler. Subprocess-isolated so nothing
+// in the test runner touches readableFlowing.
+describe.each([
+  ["net.createServer 'connection'", "net-server-accepted-socket-pause-fixture.js"],
+  ["tls.createServer 'secureConnection'", "tls-server-accepted-socket-pause-fixture.js"],
+])("accepted socket honors pause() made inside the %s handler", (_, fixture) => {
+  it("leaves readableFlowing false and delivers every byte after resume()", async () => {
+    await using proc = Bun.spawn({
+      cmd: [bunExe(), join(import.meta.dir, fixture)],
+      env: bunEnv,
+      stdout: "pipe",
+      stderr: "pipe",
+    });
+    const [stdout, stderr, exitCode] = await Promise.all([proc.stdout.text(), proc.stderr.text(), proc.exited]);
+    expect(stderr).toBe("");
+    expect(stdout.trim().split("\n")).toEqual(["flowing false", "backpressured true", "delivered true"]);
+    expect(exitCode).toBe(0);
+  });
+});