2 files changed, 49 insertions, 3 deletions

diff --git a/src/Root.cpp b/src/Root.cpp
index 99dabc099..36fd067b3 100644
--- a/src/Root.cpp
+++ b/src/Root.cpp
@@ -347,7 +347,6 @@ void cRoot::LoadGlobalSettings()
 void cRoot::LoadWorlds(cSettingsRepositoryInterface & a_Settings, bool a_IsNewIniFile)
 {
 	// First get the default world
-	AString DefaultWorldName = a_Settings.GetValueSet("Worlds", "DefaultWorld", "world");
 	if (a_IsNewIniFile)
 	{
 		a_Settings.AddValue("Worlds", "World", "world_nether");
@@ -359,11 +358,58 @@ void cRoot::LoadWorlds(cSettingsRepositoryInterface & a_Settings, bool a_IsNewIn
 		return;
 	}
 
+	AString DefaultWorldName = a_Settings.GetValueSet("Worlds", "DefaultWorld", "world");
 	m_pDefaultWorld = new cWorld(DefaultWorldName.c_str());
 	m_WorldsByName[ DefaultWorldName ] = m_pDefaultWorld;
+	auto Worlds = a_Settings.GetValues("Worlds");
+
+	// Fix servers that have default world configs created prior to #2815. See #2810.
+	// This can probably be removed several years after 2016
+	// We start by inspecting the world linkage and determining if it's the default one
+	if (DefaultWorldName == "world")
+	{
+		auto DefaultWorldIniFile= cpp14::make_unique<cIniFile>();
+		assert(DefaultWorldIniFile->ReadFile("world/world.ini"));
+		AString NetherName = DefaultWorldIniFile->GetValue("LinkedWorlds", "NetherWorldName", "");
+		AString EndName = DefaultWorldIniFile->GetValue("LinkedWorlds", "EndWorldName", "");
+		if ((NetherName.compare("world_nether") == 0) && (EndName.compare("world_end") == 0))
+		{
+			// This is a default world linkage config, see if the nether and end are in settings.ini
+			// If both of them are not in settings.ini, then this is a pre-#2815 default config
+			// so we add them to settings.ini
+			// Note that if only one of them is not in settings.ini, it's nondefault and we don't touch it
+
+			bool NetherInSettings = false;
+			bool EndInSettings = false;
+
+			for (auto WorldNameValue : Worlds)
+			{
+				AString ValueName = WorldNameValue.first;
+				if (ValueName.compare("World") != 0)
+				{
+					continue;
+				}
+				AString WorldName = WorldNameValue.second;
+				if (WorldName.compare("world_nether") == 0)
+				{
+					NetherInSettings = true;
+				}
+				else if (WorldName.compare("world_end") == 0)
+				{
+					EndInSettings = true;
+				}
+			}
+
+			if ((!NetherInSettings) && (!EndInSettings))
+			{
+				a_Settings.AddValue("Worlds", "World", "world_nether");
+				a_Settings.AddValue("Worlds", "World", "world_end");
+				Worlds = a_Settings.GetValues("Worlds");  // Refresh the Worlds list so that the rest of the function works as usual
+			}
+		}
+	}
 
 	// Then load the other worlds
-	auto Worlds = a_Settings.GetValues("Worlds");
 	if (Worlds.size() <= 0)
 	{
 		return;
diff --git a/src/Root.h b/src/Root.h
index 064752ab4..261dac29f 100644
--- a/src/Root.h
+++ b/src/Root.h
@@ -224,7 +224,7 @@ private:
 	void LoadGlobalSettings();
 
 	/** Loads the worlds from settings.ini, creates the worldmap */
-	void LoadWorlds(cSettingsRepositoryInterface & a_Settings, bool a_NewIniFile);
+	void LoadWorlds(cSettingsRepositoryInterface & a_Settings, bool a_IsNewIniFile);
 
 	/** Starts each world's life */
 	void StartWorlds(void);