feat(master): UPDATE_STATUS from the dashboard, logged when it changes

Appended message ID 50 (dashboard -> master): the update check's state and a
one-line summary. Master logs it whenever the summary changes, so the first
one after master starts says when an update is out.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

dCommon/dEnums/MessageType/Master.h

@@ -102,5 +102,8 @@ namespace MessageType {
 		WORLD_RELOAD,
 		// Master -> dashboard: each running zone's files, whether they changed on disk, and which instances are stale
 		WORLD_FILES_STATUS,
+
+		// Dashboard -> master: what the update check found about this build (see UpdateStatus.h), for master's log
+		UPDATE_STATUS,
 	};
 }

dMasterServer/MasterServer.cpp

@@ -63,6 +63,7 @@
 #include "CDClientReloader.h"
 #include "WorldReloader.h"
 #include "master/WorldFiles.h"
+#include "master/UpdateStatus.h"
 #include "BuildInfo.h"
 
 #ifdef DARKFLAME_PLATFORM_UNIX
@@ -1211,6 +1212,14 @@ namespace {
 		Game::lastSignal = -1;
 	}
 
+	// The dashboard's update check: logged when what it says changes (so the first one after master starts, and news)
+	void OnUpdateStatus(const UpdateStatus& status, const SystemAddress& sysAddr) {
+		static std::string lastSummary;
+		if (sysAddr != dashboardServerMasterPeerSysAddr || status.summary.empty() || status.summary == lastSummary) return;
+		lastSummary = status.summary;
+		LOG("%s", status.summary.c_str());
+	}
+
 	void OnMessageCaptureControl(const MessageCaptureControl& control, const SystemAddress& sysAddr) {
 		// Only the dashboard starts message captures; every world gets it, and the one with the player acts on it
 		if (sysAddr != dashboardServerMasterPeerSysAddr) {
@@ -1270,6 +1279,7 @@ namespace {
 			handlers.On<ConfigReload>(Master::CONFIG_RELOAD, OnConfigReload);
 			handlers.On<InstanceShutdown>(Master::INSTANCE_SHUTDOWN, OnInstanceShutdown);
 			handlers.On<DashboardShutdown>(Master::DASHBOARD_SHUTDOWN, OnDashboardShutdown);
+			handlers.On<UpdateStatus>(Master::UPDATE_STATUS, OnUpdateStatus);
 			// Only world servers report game writes; pass them on unchanged
 			handlers.On<DataChanged>(Master::DATA_CHANGED, ForwardWorldToDashboard<DataChanged>);
 			handlers.On<MessageCaptureControl>(Master::MESSAGE_CAPTURE_CONTROL, OnMessageCaptureControl);

dNet/master/UpdateStatus.h

@@ -0,0 +1,35 @@
+#ifndef __UPDATESTATUS__H__
+#define __UPDATESTATUS__H__
+
+#include <cstdint>
+#include <string>
+
+#include "BitStream.h"
+#include "BitStreamUtils.h"
+#include "DashboardMessages.h"
+#include "MessageType/Master.h"
+
+/**
+ * UPDATE_STATUS (dashboard -> master): what the dashboard's update check found, sent after each check and when the
+ * link to master comes up, so master's log says when a newer release or newer commits are out. Nothing is updated.
+ */
+struct UpdateStatus : public LUBitStream {
+	UpdateStatus() : LUBitStream(ServiceType::MASTER, MessageType::Master::UPDATE_STATUS) {}
+
+	static constexpr uint16_t MAX_SUMMARY = 1024;
+
+	// UpdateCheck::eState: 0 not checked, 1 up to date, 2 update available, 3 the check failed
+	uint8_t state{};
+	std::string summary; // one line for the log
+
+	void Serialize(RakNet::BitStream& stream) const override {
+		stream.Write(state);
+		DashboardMessages::WriteText(stream, summary, MAX_SUMMARY);
+	}
+
+	bool Deserialize(RakNet::BitStream& stream) override {
+		return stream.Read(state) && DashboardMessages::ReadText(stream, summary, MAX_SUMMARY);
+	}
+};
+
+#endif //!__UPDATESTATUS__H__

tests/dCommonTests/MessageIdPinTests.cpp

@@ -1816,6 +1816,7 @@ static_assert(static_cast<int64_t>(MessageType::Master::CDCLIENT_RELOAD) == 46);
 static_assert(static_cast<int64_t>(MessageType::Master::WORLD_FILES) == 47);
 static_assert(static_cast<int64_t>(MessageType::Master::WORLD_RELOAD) == 48);
 static_assert(static_cast<int64_t>(MessageType::Master::WORLD_FILES_STATUS) == 49);
+static_assert(static_cast<int64_t>(MessageType::Master::UPDATE_STATUS) == 50);
 
 // MessageType::Server: 3 enumerators
 static_assert(static_cast<int64_t>(MessageType::Server::VERSION_CONFIRM) == 0);

tests/dGameTests/dNetTests/MasterPacketsTests.cpp

@@ -6,6 +6,7 @@
 #include "master/WorldFiles.h"
 #include "master/MessageCapture.h"
 #include "master/PlayerAction.h"
+#include "master/UpdateStatus.h"
 #include "PacketDispatcher.h"
 #include "PacketTestUtils.h"
 #include "Game.h"
@@ -672,6 +673,31 @@ TEST(MasterPacketsTests, WorldFilesStatus) {
 	EXPECT_EQ(read.zones, status.zones);
 }
 
+TEST(MasterPacketsTests, UpdateStatus) {
+	UpdateStatus status;
+	status.state = 2;
+	status.summary = "Update available: release v3.1.0 (this server is running release v3.0.0)";
+	ExpectHeaderThenSerialize(status, MessageType::Master::UPDATE_STATUS);
+
+	RakNet::BitStream stream;
+	status.Serialize(stream);
+	UpdateStatus read;
+	ASSERT_TRUE(read.Deserialize(stream));
+	EXPECT_EQ(read.state, 2);
+	EXPECT_EQ(read.summary, status.summary);
+
+	// Longer than the cap: cut on the way out, refused on the way in
+	status.summary.assign(UpdateStatus::MAX_SUMMARY + 10, 'x');
+	RakNet::BitStream cut;
+	status.Serialize(cut);
+	ASSERT_TRUE(read.Deserialize(cut));
+	EXPECT_EQ(read.summary.size(), UpdateStatus::MAX_SUMMARY);
+	RakNet::BitStream tooLong;
+	tooLong.Write<uint8_t>(1);
+	tooLong.Write<uint16_t>(UpdateStatus::MAX_SUMMARY + 1);
+	EXPECT_FALSE(read.Deserialize(tooLong));
+}
+
 // A master without the outdated flags (written after the endpoints) still reads: nothing is outdated
 TEST(MasterPacketsTests, ServerListWithoutOutdatedFlags) {
 	MasterPackets::ServerListResponse response;