Add connection error handling for NvimApi usage

MsgPackRpc/MsgPackRpc/UnixDomainSocketConnection.m

@@ -89,7 +89,7 @@ static void socket_call_back(
   if ((_native_socket = socket(AF_UNIX, SOCK_STREAM, 0)) == -1) {
     NSLog(@"Error: Unix domain socket NULL!");
     return [NSError errorWithDomain:NSPOSIXErrorDomain code:-1 userInfo:@{
-        NSLocalizedDescriptionKey: @"Unix domain socket is NULL.",
+        NSLocalizedDescriptionKey: @"Could not create unix domain socket.",
     }];
   }
 
@@ -134,7 +134,7 @@ static void socket_call_back(
 }
 
 - (void)disconnectAndStop {
-  if (CFSocketIsValid(_socket)) {
+  if (_socket != NULL && CFSocketIsValid(_socket)) {
     CFRunLoopStop(_run_loop);
     CFSocketInvalidate(_socket);
     [_thread cancel];

NvimView/NvimView/NvimView+Resize.swift

@@ -4,6 +4,7 @@
  */
 
 import Cocoa
+import NvimMsgPack
 
 extension NvimView {
 
@@ -57,7 +58,14 @@ extension NvimView {
     self.logger.info("=== Starting neovim...")
     let noErrorDuringInitialization = self.uiClient.runLocalServerAndNeoVim(withWidth: size.width, height: size.height)
 
-    try? self.nvim.connect()
+    do {
+      try self.nvim.connect()
+    } catch {
+      logger.fault("Could not connect to nvim: \(error)")
+      self.nvim.disconnect()
+      self.ipcBecameInvalid(String(describing: error))
+      return
+    }
 
     if noErrorDuringInitialization == false {
       self.logger.fault("There was an error launching neovim.")

NvimView/NvimView/NvimView+UiBridge.swift

@@ -218,6 +218,7 @@ extension NvimView {
       self.delegate?.ipcBecameInvalid(reason: reason)
 
       self.bridgeLogger.error("Force-closing due to IPC error.")
+      self.nvim.disconnect()
       self.uiClient.forceQuit()
     }
   }