In CAP messages, handle the last arg as a list of capabilities

Instead of just one. This fixes the issue of the "trailing whitespace" since we
now split it on ' '

Fix #3442

src/irc/irc_client.cpp

@@ -1340,19 +1340,22 @@ long int IrcClient::get_throttle_limit() const
 void IrcClient::on_cap(const IrcMessage &message)
 {
   const auto& sub_command = message.arguments[1];
-  const auto& cap = message.arguments[2];
+  const auto& caps = utils::split(message.arguments[2], ' ', false);
-  auto it = this->capabilities.find(cap);
+  for (const auto& cap: caps)
-  if (it == this->capabilities.end())
     {
-      log_warning("Received a CAP message for something we didn’t ask, or that we already handled.");
+      auto it = this->capabilities.find(cap);
-      return;
+      if (it == this->capabilities.end())
+        {
+          log_warning("Received a CAP message for something we didn’t ask, or that we already handled: [", cap, "]");
+          return;
+        }
+      Capability& capability = it->second;
+      if (sub_command == "ACK")
+        capability.on_ack();
+      else if (sub_command == "NACK")
+        capability.on_nack();
+      this->capabilities.erase(it);
     }
-  Capability& capability = it->second;
-  if (sub_command == "ACK")
-    capability.on_ack();
-  else if (sub_command == "NACK")
-    capability.on_nack();
-  this->capabilities.erase(it);
   if (this->capabilities.empty())
     this->cap_end();
 }

tests/utils.cpp

@@ -28,6 +28,9 @@ TEST_CASE("String split")
   CHECK(splitted.size() == 2);
   CHECK(splitted[0] == "");
   CHECK(splitted[1] == "a");
+  splitted = utils::split("multi-prefix ", ' ');
+  CHECK(splitted[0] == "multi-prefix");
+  CHECK(splitted.size() == 1);
 }
 
 TEST_CASE("tolower")