fix(runtime): improve IPC reliability + organization pass on that code (#6475)

* dfghj

* Handle messages that did not finish

* tidy

* ok

* a

* Merge remote-tracking branch 'origin/main' into dave/ipc-fixes

* test failures

---------

Co-authored-by: Jarred Sumner <jarred@jarredsumner.com>

src/bun.js/javascript.zig

@@ -294,13 +294,8 @@ pub export fn Bun__Process__send(
         return .zero;
     }
     var vm = globalObject.bunVM();
-    if (vm.ipc) |ipc| {
-        const fd = ipc.socket.fd();
-        const success = IPC.serializeJSValueForSubprocess(
-            globalObject,
-            callFrame.argument(0),
-            fd,
-        );
+    if (vm.ipc) |ipc_instance| {
+        const success = ipc_instance.ipc.serializeAndSend(globalObject, callFrame.argument(0));
         return if (success) .undefined else .zero;
     } else {
         globalObject.throw("IPC Socket is no longer open.", .{});
@@ -373,6 +368,14 @@ pub export fn Bun__onDidAppendPlugin(jsc_vm: *VirtualMachine, globalObject: *JSG
     jsc_vm.bundler.linker.plugin_runner = &jsc_vm.plugin_runner.?;
 }
 
+// pub fn getGlobalExitCodeForPipeFailure() u8 {
+//     if (VirtualMachine.is_main_thread_vm) {
+//         return VirtualMachine.get().exit_handler.exit_code;
+//     }
+
+//     return 0;
+// }
+
 pub const ExitHandler = struct {
     exit_code: u8 = 0,
 
@@ -2803,9 +2806,8 @@ pub const VirtualMachine = struct {
 
     pub const IPCInstance = struct {
         globalThis: ?*JSGlobalObject,
-        socket: IPC.Socket,
         uws_context: *uws.SocketContext,
-        ipc_buffer: bun.ByteList,
+        ipc: IPC.IPCData,
 
         pub fn handleIPCMessage(
             this: *IPCInstance,
@@ -2855,13 +2857,13 @@ pub const VirtualMachine = struct {
         var instance = bun.default_allocator.create(IPCInstance) catch @panic("OOM");
         instance.* = .{
             .globalThis = this.global,
-            .socket = socket,
             .uws_context = context,
-            .ipc_buffer = bun.ByteList{},
+            .ipc = .{ .socket = socket },
         };
         var ptr = socket.ext(*IPCInstance);
         ptr.?.* = instance;
         this.ipc = instance;
+        instance.ipc.writeVersionPacket();
     }
     comptime {
         if (!JSC.is_bindgen)