fix for sonar

application/application.cpp

@@ -31,6 +31,7 @@ http://mozilla.org/MPL/2.0/.
 #include "utilities/dictionary.h"
 #include "version_info.h"
 #include <chrono>
+#include <format>
 #include "utilities/translation.h"
 
 #if WITH_DISCORD_RPC
@@ -320,9 +321,11 @@ int eu07_application::init(int Argc, char *Argv[])
 		return result;
 	}
 
-	// the run's seed, settled once and kept in Globals: the engines come out of it
+	// the run's seed, settled once and kept in Globals: the engines come out of it.
+	// narrowed on purpose - mt19937 and seed_of() both work on 32 bits, and that is
+	// the seed somebody can write down and pass on
 	if (!Global.random_seed)
-		Global.random_seed = true_random_seed();
+		Global.random_seed = static_cast<std::uint32_t>(true_random_seed());
 	Global.random_engine.seed(Global.random_seed);
 	Global.local_random_engine.seed(Global.random_seed);
 
@@ -1149,7 +1152,7 @@ int eu07_application::init_settings(int Argc, char *Argv[])
 			if (i + 1 < Argc)
 			{
 				Global.random_seed = seed_of(Argv[++i]);
-				WriteLog("seed given on the command line: " + std::string(Argv[i]) + " -> " + std::to_string(Global.random_seed));
+				WriteLog(std::format("seed given on the command line: {} -> {}", Argv[i], Global.random_seed));
 			}
 		}
 		else
@@ -1434,7 +1437,7 @@ int eu07_application::init_data()
 
 int eu07_application::init_modes()
 {
-	Global.local_random_engine.seed(true_random_seed());
+	Global.local_random_engine.seed(static_cast<std::mt19937::result_type>(true_random_seed()));
 
 	if ((!Global.network_servers.empty() || Global.network_client) && Global.SceneryFile.empty())
 	{

utilities/utilities.cpp

@@ -29,6 +29,7 @@ Copyright (C) 2007-2014 Maciej Cierniak
 #include "utilities/Globals.h"
 #include "utilities/parser.h"
 #include "utilities/U8.h"
+#include "utilities/Logs.h"
 
 
 
@@ -142,21 +143,28 @@ std::uint64_t true_random_seed()
 	try
 	{
 		std::random_device rd;
-		if (rd.entropy()  > 0.0)
+		if (rd.entropy() > 0.0)
 		{
-			std::uint32_t high = rd();
+			// NOTE: both halves have to be 64 bit wide before the shift - shifting a std::uint32_t
-			std::uint32_t low = rd();
+			// by 32 is undefined behaviour, and drops the high half of the seed
+			std::uint64_t const high{rd()};
+			std::uint64_t const low{rd()};
 			return (high << 32) | low;
 		}
 	}
-	catch (...) {}
+	catch (std::exception const &Error)
+	{
+		// std::random_device throws when the machine has no usable hardware entropy source;
+		// the clock below stands in for it, which is worth saying out loud since it is a
+		// weaker seed than the caller asked for
+		WriteLog(std::format("random: no hardware entropy source ({}), seeding from the clock instead", Error.what()));
+	}
 	return static_cast<std::uint64_t>(std::chrono::high_resolution_clock::now().time_since_epoch().count());
 }
 
 std::uint32_t seed_of(std::string const &Text)
 {
-	std::uint32_t number{};
+	if (std::uint32_t number{}; std::from_chars(Text.data(), Text.data() + Text.size(), number).ec == std::errc{})
-	if (std::from_chars(Text.data(), Text.data() + Text.size(), number).ec == std::errc{})
 	{
 		return number;
 	}