[Qt] make PaymentServer::ipcParseCommandLine void

- the function only returned true, so make it void
- add a comment about payment request network detection

src/qt/paymentserver.cpp

@@ -184,7 +184,7 @@ void PaymentServer::LoadRootCAs(X509_STORE* _store)
 // Warning: ipcSendCommandLine() is called early in init,
 // so don't use "emit message()", but "QMessageBox::"!
 //
-bool PaymentServer::ipcParseCommandLine(int argc, char* argv[])
+void PaymentServer::ipcParseCommandLine(int argc, char* argv[])
 {
     for (int i = 1; i < argc; i++)
     {
@@ -192,6 +192,10 @@ bool PaymentServer::ipcParseCommandLine(int argc, char* argv[])
         if (arg.startsWith("-"))
             continue;
 
+        // If the bitcoin: URI contains a payment request, we are not able to detect the
+        // network as that would require fetching and parsing the payment request.
+        // That means clicking such an URI which contains a testnet payment request
+        // will start a mainnet instance and throw a "wrong network" error.
         if (arg.startsWith(BITCOIN_IPC_PREFIX, Qt::CaseInsensitive)) // bitcoin: URI
         {
             savedPaymentRequests.append(arg);
@@ -235,7 +239,6 @@ bool PaymentServer::ipcParseCommandLine(int argc, char* argv[])
             qWarning() << "PaymentServer::ipcSendCommandLine : Payment request file does not exist: " << arg;
         }
     }
-    return true;
 }
 
 //