Correctly handle failing to connect to the given session in client mode

src/main.cc

@@ -228,6 +228,11 @@ int run_client(const String& session, const String& init_command)
         fputs("disconnected from server\n", stderr);
         return -1;
     }
+    catch (connection_failed& e)
+    {
+        fputs(e.what(), stderr);
+        return -1;
+    }
     return 0;
 }
 
@@ -254,7 +259,15 @@ int kakoune(const ParametersParser& parser)
             }
             command += String{buf, buf + count};
         }
-        send_command(parser.option_value("p"), command);
+        try
+        {
+            send_command(parser.option_value("p"), command);
+        }
+        catch (connection_failed& e)
+        {
+            fputs(e.what(), stderr);
+            return -1;
+        }
         return 0;
     }
 

src/remote.cc

@@ -448,7 +448,7 @@ std::unique_ptr<RemoteClient> connect_to(const String& session, std::unique_ptr<
     addr.sun_family = AF_UNIX;
     strncpy(addr.sun_path, filename.c_str(), sizeof(addr.sun_path) - 1);
     if (connect(sock, (sockaddr*)&addr, sizeof(addr.sun_path)) == -1)
-        throw runtime_error("connect to " + filename + " failed");
+        throw connection_failed(filename);
 
     return std::unique_ptr<RemoteClient>{new RemoteClient{sock, std::move(ui), init_command}};
 }
@@ -463,7 +463,7 @@ void send_command(const String& session, const String& command)
     addr.sun_family = AF_UNIX;
     strncpy(addr.sun_path, filename.c_str(), sizeof(addr.sun_path) - 1);
     if (connect(sock, (sockaddr*)&addr, sizeof(addr.sun_path)) == -1)
-        throw runtime_error("connect to " + filename + " failed");
+        throw connection_failed(filename);
 
     {
         Message msg(sock);

src/remote.hh

@@ -10,6 +10,13 @@ namespace Kakoune
 
 struct peer_disconnected {};
 
+struct connection_failed : runtime_error
+{
+    connection_failed(const String& filename)
+        : runtime_error{"connect to " + filename + " failed"}
+    {}
+};
+
 // A remote client handle communication between a client running on the server
 // and a user interface running on the local process.
 class RemoteClient