[lldb] Fix crash when launching in terminal

[JDevlieghere]

Summary

This patch fixes a crash when using process launch -t to launch the inferior from a TTY. The issue is that on Darwin, Host.mm is calling ConnectionFileDescriptor::Connect without a socket_id_callback_type. The overload passes nullptr as the function ref, which gets called unconditionally as the socket_id_callback. One potential way to fix this is to change all the lambdas to include a null check, but instead I went with a NOOP.

The patch doesn't include a test even though it's trivial to write one. The reason is that we really don't want the test suite spawning (and leaving around) Terminal.app instances on every run.

[labath]

One could add a unit test for the CFD overload, though, as this appears to be the only callsite (or other callsites were equally untested and broken), we could also remove it altogether.

lldb/source/Host/posix/ConnectionFileDescriptorPosix.cpp

 }
 
 bool ConnectionFileDescriptor::IsConnected() const {
   return m_io_sp && m_io_sp->IsValid();
 }
 
 ConnectionStatus ConnectionFileDescriptor::Connect(llvm::StringRef path,
                                                    Status *error_ptr) {
-  return Connect(path, nullptr, error_ptr);
+  return Connect(
+      path, [](llvm::StringRef) {}, error_ptr);
 }
 
 ConnectionStatus
 ConnectionFileDescriptor::Connect(llvm::StringRef path,
                                   socket_id_callback_type socket_id_callback,
                                   Status *error_ptr) {
   std::lock_guard<std::recursive_mutex> guard(m_mutex);
   Log *log = GetLog(LLDBLog::Connection);

lldb/unittests/Host/ConnectionFileDescriptorTest.cpp

 class ConnectionFileDescriptorTest : public testing::Test {
 public:
   SubsystemRAII<Socket> subsystems;
 
   void TestGetURI(std::string ip) {
     std::unique_ptr<TCPSocket> socket_a_up;
     std::unique_ptr<TCPSocket> socket_b_up;
     CreateTCPConnectedSockets(ip, &socket_a_up, &socket_b_up);
-    auto socket = socket_a_up.release();
+    auto *socket = socket_a_up.release();
     ConnectionFileDescriptor connection_file_descriptor(socket);
 
     std::string uri(connection_file_descriptor.GetURI());
     EXPECT_EQ((URI{"connect", ip, socket->GetRemotePortNumber(), "/"}),
               URI::Parse(uri).getValue());
   }
+
+  void TestConnect(std::string ip, std::string path) {
+    std::unique_ptr<TCPSocket> socket_a_up;
+    std::unique_ptr<TCPSocket> socket_b_up;
+    CreateTCPConnectedSockets(ip, &socket_a_up, &socket_b_up);
+    auto *socket = socket_a_up.release();
+    ConnectionFileDescriptor connection_file_descriptor(socket);
+    connection_file_descriptor.Connect(path, nullptr);
+  }
 };
 
 TEST_F(ConnectionFileDescriptorTest, TCPGetURIv4) {
   if (!HostSupportsIPv4())
     return;
   TestGetURI("127.0.0.1");
 }
 
 TEST_F(ConnectionFileDescriptorTest, TCPGetURIv6) {
   if (!HostSupportsIPv6())
     return;
   TestGetURI("::1");
 }
+
+TEST_F(ConnectionFileDescriptorTest, Connectv4) {
+  if (!HostSupportsIPv4())
+    return;
+  TestConnect("127.0.0.1", "accept://127.0.0.1");
+}
+
+TEST_F(ConnectionFileDescriptorTest, Connectv6) {
+  if (!HostSupportsIPv6())
+    return;
+  TestConnect("::1", "accept://::1");
+}