Add MVP reconnect snapshots

AGRARIAN_DEVELOPMENT_ROADMAP.md

@@ -725,7 +725,9 @@ Target deliverable: A small group can join a server, spawn into one biome, gathe
 - [x] Add basic latency testing. Added an MVP latency test plan with clean LAN,
   mild WAN, and rough WAN Unreal packet-simulation profiles plus a Windows
   helper script for the test console commands.
-- [ ] Add disconnect/reconnect handling.
+- [x] Add disconnect/reconnect handling. Added MVP player reconnect snapshots:
+  logout saves transform, survival, care history, and inventory for the player,
+  and restart/spawn restores the matching snapshot when the same player returns.
 
 ## 0.1.M Persistence MVP
 

Docs/MultiplayerNetworkingDesign.md

@@ -271,11 +271,14 @@ Initial latency testing should cover:
 
 MVP behavior:
 
-- disconnect removes the player's pawn from active control;
+- disconnect removes the player's pawn from active control and captures a
-- player survival/inventory can be preserved by the current persistence
+  player reconnect snapshot during `AAgrarianGameGameMode::Logout`;
-  mechanism if available;
+- the reconnect snapshot preserves transform, survival, care history, and
-- reconnect may respawn the player at the last saved state or MVP spawn point,
+  inventory through `UAgrarianPersistenceSubsystem::SavePlayerSnapshot`;
-  depending on persistence maturity;
+- reconnect/spawn restores the matching snapshot in
+  `AAgrarianGameGameMode::RestartPlayer` through
+  `UAgrarianPersistenceSubsystem::RestorePlayerSnapshot`;
+- if no matching snapshot exists, the player uses the normal MVP spawn point;
 - server should not crash or leak active interaction/build state when a player
   disconnects mid-action.
 

Scripts/verify_disconnect_reconnect_handling.py

@@ -0,0 +1,82 @@
+#!/usr/bin/env python3
+"""Validate MVP disconnect/reconnect snapshot handling."""
+
+from pathlib import Path
+import sys
+
+ROOT = Path(__file__).resolve().parents[1]
+
+
+def read(relative_path: str) -> str:
+    path = ROOT / relative_path
+    if not path.exists():
+        raise AssertionError(f"Missing required file: {relative_path}")
+    return path.read_text(encoding="utf-8")
+
+
+def require(content: str, needle: str, context: str) -> None:
+    if needle not in content:
+        raise AssertionError(f"Missing {needle!r} in {context}")
+
+
+def main() -> int:
+    errors: list[str] = []
+    checks = {
+        "Source/AgrarianGame/AgrarianPersistenceSubsystem.h": [
+            "SavePlayerSnapshot",
+            "RestorePlayerSnapshot",
+            "CapturePlayerIntoSave",
+            "RestorePlayerFromSave",
+        ],
+        "Source/AgrarianGame/AgrarianPersistenceSubsystem.cpp": [
+            "bool UAgrarianPersistenceSubsystem::SavePlayerSnapshot",
+            "bool UAgrarianPersistenceSubsystem::RestorePlayerSnapshot",
+            "SaveGame->Players.RemoveAll",
+            "SavedPlayer.Transform = Character->GetActorTransform()",
+            "SavedPlayer.Survival = SurvivalComponent->Survival",
+            "SavedPlayer.CareHistory = SurvivalComponent->CareHistory",
+            "SavedPlayer.Inventory = InventoryComponent->Items",
+            "Character->SetActorTransform",
+            "InventoryComponent->RestoreSavedItems",
+        ],
+        "Source/AgrarianGame/AgrarianGameGameMode.h": [
+            "virtual void RestartPlayer(AController* NewPlayer) override;",
+            "virtual void Logout(AController* Exiting) override;",
+        ],
+        "Source/AgrarianGame/AgrarianGameGameMode.cpp": [
+            "RestorePlayerSnapshot(AgrarianCharacter)",
+            "SavePlayerSnapshot(AgrarianCharacter)",
+            "Super::RestartPlayer(NewPlayer)",
+            "Super::Logout(Exiting)",
+        ],
+        "Docs/MultiplayerNetworkingDesign.md": [
+            "player reconnect snapshot",
+            "SavePlayerSnapshot",
+            "RestorePlayerSnapshot",
+            "normal MVP spawn point",
+        ],
+        "AGRARIAN_DEVELOPMENT_ROADMAP.md": [
+            "[x] Add disconnect/reconnect handling.",
+            "MVP player reconnect snapshots",
+        ],
+    }
+
+    for relative_path, needles in checks.items():
+        try:
+            content = read(relative_path)
+            for needle in needles:
+                require(content, needle, relative_path)
+        except AssertionError as exc:
+            errors.append(str(exc))
+
+    if errors:
+        for error in errors:
+            print(f"ERROR: {error}", file=sys.stderr)
+        return 1
+
+    print("PASS: MVP disconnect/reconnect snapshot handling is wired and documented.")
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())

Source/AgrarianGame/AgrarianGameGameMode.cpp

@@ -1,11 +1,37 @@
 // Copyright Epic Games, Inc. All Rights Reserved.
 
 #include "AgrarianGameGameMode.h"
+#include "AgrarianGameCharacter.h"
 #include "AgrarianDebugHUD.h"
 #include "AgrarianGameState.h"
+#include "AgrarianPersistenceSubsystem.h"
 
 AAgrarianGameGameMode::AAgrarianGameGameMode()
 {
 	GameStateClass = AAgrarianGameState::StaticClass();
 	HUDClass = AAgrarianDebugHUD::StaticClass();
 }
+
+void AAgrarianGameGameMode::RestartPlayer(AController* NewPlayer)
+{
+	Super::RestartPlayer(NewPlayer);
+
+	AAgrarianGameCharacter* AgrarianCharacter = NewPlayer ? Cast<AAgrarianGameCharacter>(NewPlayer->GetPawn()) : nullptr;
+	UAgrarianPersistenceSubsystem* Persistence = GetGameInstance() ? GetGameInstance()->GetSubsystem<UAgrarianPersistenceSubsystem>() : nullptr;
+	if (AgrarianCharacter && Persistence && Persistence->RestorePlayerSnapshot(AgrarianCharacter))
+	{
+		UE_LOG(LogTemp, Log, TEXT("Agrarian restored reconnect snapshot for %s."), *AgrarianCharacter->GetName());
+	}
+}
+
+void AAgrarianGameGameMode::Logout(AController* Exiting)
+{
+	AAgrarianGameCharacter* AgrarianCharacter = Exiting ? Cast<AAgrarianGameCharacter>(Exiting->GetPawn()) : nullptr;
+	UAgrarianPersistenceSubsystem* Persistence = GetGameInstance() ? GetGameInstance()->GetSubsystem<UAgrarianPersistenceSubsystem>() : nullptr;
+	if (AgrarianCharacter && Persistence)
+	{
+		Persistence->SavePlayerSnapshot(AgrarianCharacter);
+	}
+
+	Super::Logout(Exiting);
+}

Source/AgrarianGame/AgrarianGameGameMode.h

@@ -18,6 +18,9 @@ public:
 	
 	/** Constructor */
 	AAgrarianGameGameMode();
+
+	virtual void RestartPlayer(AController* NewPlayer) override;
+	virtual void Logout(AController* Exiting) override;
 };
 
 

Source/AgrarianGame/AgrarianPersistenceSubsystem.cpp

@@ -173,24 +173,7 @@ int32 UAgrarianPersistenceSubsystem::CapturePlayers(UAgrarianSaveGame* SaveGame)
 	SaveGame->Players.Reset();
 	for (const AAgrarianGameCharacter* Character : Players)
 	{
-		const UAgrarianSurvivalComponent* SurvivalComponent = Character ? Character->GetSurvivalComponent() : nullptr;
+		CapturePlayerIntoSave(Character, SaveGame);
-		if (!Character || !SurvivalComponent)
-		{
-			continue;
-		}
-
-		FAgrarianSavedPlayer SavedPlayer;
-		SavedPlayer.PlayerId = GetPlayerPersistenceId(Character);
-		SavedPlayer.Transform = Character->GetActorTransform();
-		SavedPlayer.Survival = SurvivalComponent->Survival;
-		SavedPlayer.CareHistory = SurvivalComponent->CareHistory;
-
-		if (const UAgrarianInventoryComponent* InventoryComponent = Character->GetInventoryComponent())
-		{
-			SavedPlayer.Inventory = InventoryComponent->Items;
-		}
-
-		SaveGame->Players.Add(SavedPlayer);
 	}
 
 	return SaveGame->Players.Num();
@@ -209,38 +192,32 @@ int32 UAgrarianPersistenceSubsystem::RestorePlayers(const UAgrarianSaveGame* Sav
 	int32 RestoredCount = 0;
 	for (AAgrarianGameCharacter* Character : Players)
 	{
-		UAgrarianSurvivalComponent* SurvivalComponent = Character ? Character->GetSurvivalComponent() : nullptr;
+		if (RestorePlayerFromSave(Character, SaveGame))
-		if (!Character || !SurvivalComponent)
 		{
-			continue;
-		}
-
-		const FString PlayerId = GetPlayerPersistenceId(Character);
-		const FAgrarianSavedPlayer* SavedPlayer = SaveGame->Players.FindByPredicate(
-			[&PlayerId](const FAgrarianSavedPlayer& Candidate)
-			{
-				return Candidate.PlayerId == PlayerId;
-			});
-
-		if (!SavedPlayer)
-		{
-			continue;
-		}
-
-		Character->SetActorTransform(SavedPlayer->Transform, false, nullptr, ETeleportType::TeleportPhysics);
-		SurvivalComponent->ApplySavedState(SavedPlayer->Survival, SavedPlayer->CareHistory);
-
-		if (UAgrarianInventoryComponent* InventoryComponent = Character->GetInventoryComponent())
-		{
-			InventoryComponent->RestoreSavedItems(SavedPlayer->Inventory);
-		}
-
 			RestoredCount++;
 		}
+	}
 
 	return RestoredCount;
 }
 
+bool UAgrarianPersistenceSubsystem::SavePlayerSnapshot(const AAgrarianGameCharacter* Character) const
+{
+	UAgrarianSaveGame* SaveGame = LoadOrCreateSave();
+	if (!SaveGame || !CapturePlayerIntoSave(Character, SaveGame))
+	{
+		return false;
+	}
+
+	return WriteSave(SaveGame);
+}
+
+bool UAgrarianPersistenceSubsystem::RestorePlayerSnapshot(AAgrarianGameCharacter* Character) const
+{
+	const UAgrarianSaveGame* SaveGame = LoadOrCreateSave();
+	return SaveGame ? RestorePlayerFromSave(Character, SaveGame) : false;
+}
+
 int32 UAgrarianPersistenceSubsystem::CaptureResourceNodes(UAgrarianSaveGame* SaveGame) const
 {
 	if (!SaveGame)
@@ -339,6 +316,64 @@ bool UAgrarianPersistenceSubsystem::LoadCurrentWorld(int32& RestoredPlayerCount,
 	return bRestoredWorldState;
 }
 
+bool UAgrarianPersistenceSubsystem::CapturePlayerIntoSave(const AAgrarianGameCharacter* Character, UAgrarianSaveGame* SaveGame) const
+{
+	const UAgrarianSurvivalComponent* SurvivalComponent = Character ? Character->GetSurvivalComponent() : nullptr;
+	if (!Character || !SurvivalComponent || !SaveGame)
+	{
+		return false;
+	}
+
+	FAgrarianSavedPlayer SavedPlayer;
+	SavedPlayer.PlayerId = GetPlayerPersistenceId(Character);
+	SavedPlayer.Transform = Character->GetActorTransform();
+	SavedPlayer.Survival = SurvivalComponent->Survival;
+	SavedPlayer.CareHistory = SurvivalComponent->CareHistory;
+
+	if (const UAgrarianInventoryComponent* InventoryComponent = Character->GetInventoryComponent())
+	{
+		SavedPlayer.Inventory = InventoryComponent->Items;
+	}
+
+	SaveGame->Players.RemoveAll([&SavedPlayer](const FAgrarianSavedPlayer& Candidate)
+	{
+		return Candidate.PlayerId == SavedPlayer.PlayerId;
+	});
+	SaveGame->Players.Add(SavedPlayer);
+	return true;
+}
+
+bool UAgrarianPersistenceSubsystem::RestorePlayerFromSave(AAgrarianGameCharacter* Character, const UAgrarianSaveGame* SaveGame) const
+{
+	UAgrarianSurvivalComponent* SurvivalComponent = Character ? Character->GetSurvivalComponent() : nullptr;
+	if (!Character || !SurvivalComponent || !SaveGame)
+	{
+		return false;
+	}
+
+	const FString PlayerId = GetPlayerPersistenceId(Character);
+	const FAgrarianSavedPlayer* SavedPlayer = SaveGame->Players.FindByPredicate(
+		[&PlayerId](const FAgrarianSavedPlayer& Candidate)
+		{
+			return Candidate.PlayerId == PlayerId;
+		});
+
+	if (!SavedPlayer)
+	{
+		return false;
+	}
+
+	Character->SetActorTransform(SavedPlayer->Transform, false, nullptr, ETeleportType::TeleportPhysics);
+	SurvivalComponent->ApplySavedState(SavedPlayer->Survival, SavedPlayer->CareHistory);
+
+	if (UAgrarianInventoryComponent* InventoryComponent = Character->GetInventoryComponent())
+	{
+		InventoryComponent->RestoreSavedItems(SavedPlayer->Inventory);
+	}
+
+	return true;
+}
+
 void UAgrarianPersistenceSubsystem::FindPersistentComponents(TArray<UAgrarianPersistentActorComponent*>& OutComponents) const
 {
 	OutComponents.Reset();

Source/AgrarianGame/AgrarianPersistenceSubsystem.h

@@ -59,6 +59,12 @@ public:
 	UFUNCTION(BlueprintCallable, Category = "Agrarian|Persistence")
 	int32 RestorePlayers(const UAgrarianSaveGame* SaveGame) const;
 
+	UFUNCTION(BlueprintCallable, Category = "Agrarian|Persistence")
+	bool SavePlayerSnapshot(const AAgrarianGameCharacter* Character) const;
+
+	UFUNCTION(BlueprintCallable, Category = "Agrarian|Persistence")
+	bool RestorePlayerSnapshot(AAgrarianGameCharacter* Character) const;
+
 	UFUNCTION(BlueprintCallable, Category = "Agrarian|Persistence")
 	int32 CaptureResourceNodes(UAgrarianSaveGame* SaveGame) const;
 
@@ -72,6 +78,8 @@ public:
 	bool LoadCurrentWorld(int32& RestoredPlayerCount, int32& RestoredWorldActorCount, bool bClearExistingActors = true) const;
 
 protected:
+	bool CapturePlayerIntoSave(const AAgrarianGameCharacter* Character, UAgrarianSaveGame* SaveGame) const;
+	bool RestorePlayerFromSave(AAgrarianGameCharacter* Character, const UAgrarianSaveGame* SaveGame) const;
 	void FindPersistentComponents(TArray<UAgrarianPersistentActorComponent*>& OutComponents) const;
 	void FindAgrarianPlayers(TArray<AAgrarianGameCharacter*>& OutPlayers) const;
 	void FindResourceNodes(TArray<AAgrarianResourceNode*>& OutResourceNodes) const;