From c663ccd83bd2dad8c54151d64831ebbb368f77cb Mon Sep 17 00:00:00 2001
From: Alistair Smith <hi@alistair.sh>
Date: Fri, 30 May 2025 15:09:56 -0700
Subject: [PATCH] 1

---
 .../bindings/ScriptExecutionContext.cpp       | 19 +++++++++++++++++++
 src/bun.js/bindings/ScriptExecutionContext.h  |  2 ++
 src/bun.js/bindings/webcore/MessagePort.cpp   | 10 ++++++++++
 3 files changed, 31 insertions(+)

diff --git a/src/bun.js/bindings/ScriptExecutionContext.cpp b/src/bun.js/bindings/ScriptExecutionContext.cpp
index fbd519eada..0c573408af 100644
--- a/src/bun.js/bindings/ScriptExecutionContext.cpp
+++ b/src/bun.js/bindings/ScriptExecutionContext.cpp
@@ -122,6 +122,25 @@ void ScriptExecutionContext::unrefEventLoop()
     Bun__eventLoop__incrementRefConcurrently(WebCore::clientData(vm())->bunVM, -1);
 }
 
+bool ScriptExecutionContext::canSendMessage()
+{
+    us_loop_t* loop = (us_loop_t*)uws_get_loop();
+    uint32_t currentTickNr = static_cast<uint32_t>(us_loop_iteration_number(loop));
+    
+    if (lastSendTickNr != currentTickNr) {
+        messagesSentThisTick = 0;
+        lastSendTickNr = currentTickNr;
+    }
+
+    constexpr uint32_t MAX_MESSAGES_PER_TICK = 1000;
+    if (messagesSentThisTick >= MAX_MESSAGES_PER_TICK) {
+        return false;
+    }
+
+    messagesSentThisTick++;
+    return true;
+}
+
 ScriptExecutionContext::~ScriptExecutionContext()
 {
     checkConsistency();
diff --git a/src/bun.js/bindings/ScriptExecutionContext.h b/src/bun.js/bindings/ScriptExecutionContext.h
index 874f3a3892..4d36305f2a 100644
--- a/src/bun.js/bindings/ScriptExecutionContext.h
+++ b/src/bun.js/bindings/ScriptExecutionContext.h
@@ -63,6 +63,8 @@ public:
     uint32_t lastSendTickNr = -1; // Will be updated to the us_loop_t->data.iteration_nr every tick we send a message in
                                   // https://github.com/oven-sh/bun/blob/d7a517cdfc31705a6b4fb696dc834ba8d98d5d3a/packages/bun-usockets/src/internal/loop_data.h#L58
 
+    bool canSendMessage();
+
     template<bool isSSL>
     us_socket_context_t* webSocketContext()
     {
diff --git a/src/bun.js/bindings/webcore/MessagePort.cpp b/src/bun.js/bindings/webcore/MessagePort.cpp
index f70a7b5bdf..f0973054c2 100644
--- a/src/bun.js/bindings/webcore/MessagePort.cpp
+++ b/src/bun.js/bindings/webcore/MessagePort.cpp
@@ -184,6 +184,16 @@ ExceptionOr<void> MessagePort::postMessage(JSC::JSGlobalObject& state, JSC::JSVa
 
     MessageWithMessagePorts message { messageData.releaseReturnValue(), WTFMove(transferredPorts) };
 
+    auto* context = scriptExecutionContext();
+    if (!context->canSendMessage()) {
+        context->postImmediateCppTask([protectedThis = Ref { *this }, message = WTFMove(message)](ScriptExecutionContext& ctx) mutable {
+            if (protectedThis->isEntangled()) {
+                MessagePortChannelProvider::fromContext(ctx).postMessageToRemote(WTFMove(message), protectedThis->m_remoteIdentifier);
+            }
+        });
+        return {};
+    }
+
     MessagePortChannelProvider::fromContext(*protectedScriptExecutionContext()).postMessageToRemote(WTFMove(message), m_remoteIdentifier);
     return {};
 }