Fix serial console attachment silently disabled by wrong error check

serial_console_test.go

@@ -0,0 +1,27 @@
+package vz_test
+
+import (
+	"errors"
+	"os"
+	"testing"
+
+	"github.com/Code-Hex/vz/v3"
+	"github.com/Code-Hex/vz/v3/internal/objc"
+)
+
+// TestNewFileHandleSerialPortAttachment guards against a regression where the
+// constructor checked the error out-parameter pointer (always non-nil) instead
+// of the duplicated file handle, causing it to return a non-nil wrapper around a
+// NULL Objective-C object with a nil error. The serial console was silently lost.
+func TestNewFileHandleSerialPortAttachment(t *testing.T) {
+	attachment, err := vz.NewFileHandleSerialPortAttachment(os.Stdin, os.Stderr)
+	if errors.Is(err, vz.ErrUnsupportedOSVersion) {
+		t.Skipf("not supported on this macOS version: %v", err)
+	}
+	if err != nil {
+		t.Fatal(err)
+	}
+	if objc.Ptr(attachment) == nil {
+		t.Fatal("attachment wraps a NULL pointer: constructor reported success but built nothing")
+	}
+}

virtualization_11.m

@@ -454,12 +454,12 @@ void setStorageDevicesVZVirtualMachineConfiguration(void *config,
         VZFileHandleSerialPortAttachment *ret;
         @autoreleasepool {
             NSFileHandle *fileHandleForReading = newFileHandleDupFd(readFileDescriptor, error);
-            if (error != nil) {
+            if (fileHandleForReading == nil) {
                 return nil;
             }
 
             NSFileHandle *fileHandleForWriting = newFileHandleDupFd(writeFileDescriptor, error);
-            if (error != nil) {
+            if (fileHandleForWriting == nil) {
                 return nil;
             }
             ret = [[VZFileHandleSerialPortAttachment alloc]