fix copySendRight() for send rights that become dead names

Author: glessard

Sources/System/MachPort.swift

@@ -309,7 +309,7 @@ extension Mach.Port where RightType == Mach.SendRight {
 
     // name is the same because send rights are coalesced
     let kr = mach_port_insert_right(mach_task_self_, _name, _name, mach_msg_type_name_t(how))
-    if kr == KERN_INVALID_NAME {
+    if kr == KERN_INVALID_NAME || kr == KERN_INVALID_CAPABILITY {
       throw Mach.PortRightError.deadName
     }
     _machPrecondition(kr)

Tests/SystemTests/MachPortTests.swift

@@ -185,13 +185,24 @@ final class MachPortTests: XCTestCase {
     }
 
     func testCopyDeadName() throws {
+        let recv = Mach.Port<Mach.ReceiveRight>()
+        let send = recv.makeSendRight()
+        _ = consume recv // and turn `send` into a dead name
+        do {
+            let copy = try send.copySendRight()
+            _ = copy
+        }
+        catch Mach.PortRightError.deadName {
+        }
+    }
+
+    func testCopyDeadName2() throws {
         let send = Mach.Port<Mach.SendRight>(name: 0xffffffff)
         do {
             let copy = try send.copySendRight()
             _ = copy
         }
         catch Mach.PortRightError.deadName {
-            _ = send.relinquish()
         }
     }