SSP Worlds updating from 1.6 will now pop a warning message before loading, and will capture a timestamped

zip file in the minecraft dir before starting to load. Allows for people to test updates.

fml/patches/minecraft/net/minecraft/client/gui/GuiSelectWorld.java.patch

@@ -0,0 +1,18 @@
+--- ../src-base/minecraft/net/minecraft/client/gui/GuiSelectWorld.java
++++ ../src-work/minecraft/net/minecraft/client/gui/GuiSelectWorld.java
+@@ -1,5 +1,6 @@
+ package net.minecraft.client.gui;
+ 
++import cpw.mods.fml.client.FMLClientHandler;
+ import cpw.mods.fml.relauncher.Side;
+ import cpw.mods.fml.relauncher.SideOnly;
+ import java.text.DateFormat;
+@@ -179,7 +180,7 @@
+ 
+             if (this.field_146297_k.func_71359_d().func_90033_f(s))
+             {
+-                this.field_146297_k.func_71371_a(s, s1, (WorldSettings)null);
++                FMLClientHandler.instance().tryLoadExistingWorld(this, s, s1);
+             }
+         }
+     }

fml/src/main/java/cpw/mods/fml/client/ExtendedServerListData.java

@@ -1,16 +1,18 @@
 package cpw.mods.fml.client;
 
+import java.util.Map;
+
 public class ExtendedServerListData {
     public final String type;
     public final boolean isCompatible;
-    public final int modCount;
+    public final Map<String,String> modData;
     public final boolean isBlocked;
 
-    public ExtendedServerListData(String type, boolean isCompatible, int modCount, boolean isBlocked)
+    public ExtendedServerListData(String type, boolean isCompatible, Map<String,String> modData, boolean isBlocked)
     {
         this.type = type;
         this.isCompatible = isCompatible;
-        this.modCount = modCount;
+        this.modData = modData;
         this.isBlocked = isBlocked;
     }
 }

fml/src/main/java/cpw/mods/fml/client/FMLClientHandler.java

@@ -12,6 +12,8 @@
  */
 package cpw.mods.fml.client;
 
+import java.io.File;
+import java.io.FileInputStream;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
@@ -28,6 +30,7 @@ import net.minecraft.client.gui.Gui;
 import net.minecraft.client.gui.GuiIngameMenu;
 import net.minecraft.client.gui.GuiMainMenu;
 import net.minecraft.client.gui.GuiScreen;
+import net.minecraft.client.gui.GuiSelectWorld;
 import net.minecraft.client.gui.ServerListEntryNormal;
 import net.minecraft.client.multiplayer.GuiConnecting;
 import net.minecraft.client.multiplayer.ServerData;
@@ -42,6 +45,8 @@ import net.minecraft.crash.CrashReport;
 import net.minecraft.entity.Entity;
 import net.minecraft.entity.player.EntityPlayer;
 import net.minecraft.launchwrapper.Launch;
+import net.minecraft.nbt.CompressedStreamTools;
+import net.minecraft.nbt.NBTTagCompound;
 import net.minecraft.network.INetHandler;
 import net.minecraft.network.NetHandlerPlayServer;
 import net.minecraft.network.NetworkManager;
@@ -56,7 +61,10 @@ import com.google.common.collect.BiMap;
 import com.google.common.collect.HashBiMap;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableMap.Builder;
 import com.google.common.collect.Maps;
+import com.google.gson.JsonArray;
+import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import cpw.mods.fml.client.registry.RenderingRegistry;
 import cpw.mods.fml.common.DummyModContainer;
@@ -559,6 +567,46 @@ public class FMLClientHandler implements IFMLSidedHandler
         playClientBlock = new CountDownLatch(1);
     }
 
+    public File getSavesDir()
+    {
+        return new File(client.field_71412_D, "saves");
+    }
+    public void tryLoadExistingWorld(GuiSelectWorld selectWorldGUI, String dirName, String saveName)
+    {
+        File dir = new File(getSavesDir(), dirName);
+        NBTTagCompound leveldat;
+        try
+        {
+            leveldat = CompressedStreamTools.func_74796_a(new FileInputStream(new File(dir, "level.dat")));
+        }
+        catch (Exception e)
+        {
+            try
+            {
+                leveldat = CompressedStreamTools.func_74796_a(new FileInputStream(new File(dir, "level.dat_old")));
+            }
+            catch (Exception e1)
+            {
+                FMLLog.warning("There appears to be a problem loading the save %s, both level files are unreadable.", dirName);
+                return;
+            }
+        }
+        NBTTagCompound fmlData = leveldat.func_74775_l("FML");
+        if (fmlData.func_74764_b("ModItemData"))
+        {
+            showGuiScreen(new GuiOldSaveLoadConfirm(dirName, saveName, selectWorldGUI));
+        }
+        else
+        {
+            launchIntegratedServerCallback(dirName, saveName);
+        }
+    }
+
+    public void launchIntegratedServerCallback(String dirName, String saveName)
+    {
+        client.func_71371_a(dirName, saveName, (WorldSettings)null);
+    }
+
     public void showInGameModOptions(GuiIngameMenu guiIngameMenu)
     {
         showGuiScreen(new GuiIngameModOptions(guiIngameMenu));
@@ -590,9 +638,16 @@ public class FMLClientHandler implements IFMLSidedHandler
         {
             JsonObject jsonData = extraServerListData.get(originalResponse);
             String type = jsonData.get("type").getAsString();
-            int modCount = jsonData.get("modList").getAsJsonArray().size();
+            JsonArray modDataArray = jsonData.get("modList").getAsJsonArray();
             boolean moddedClientAllowed = jsonData.has("clientModsAllowed") ? jsonData.get("clientModsAllowed").getAsBoolean() : true;
-            serverDataTag.put(data, new ExtendedServerListData(type, true, modCount, !moddedClientAllowed));
+            Builder<String, String> modListBldr = ImmutableMap.<String,String>builder();
+            for (JsonElement obj : modDataArray)
+            {
+                JsonObject modObj = obj.getAsJsonObject();
+                modListBldr.put(modObj.get("modid").getAsString(), modObj.get("version").getAsString());
+            }
+
+            serverDataTag.put(data, new ExtendedServerListData(type, true, modListBldr.build(), !moddedClientAllowed));
         }
         else
         {
@@ -602,7 +657,7 @@ public class FMLClientHandler implements IFMLSidedHandler
             {
                 moddedClientAllowed = !serverDescription.endsWith(":NOFML§r");
             }
-            serverDataTag.put(data, new ExtendedServerListData("VANILLA", false, -1, !moddedClientAllowed));
+            serverDataTag.put(data, new ExtendedServerListData("VANILLA", false, ImmutableMap.<String,String>of(), !moddedClientAllowed));
         }
         startupConnectionData.countDown();
     }
@@ -621,12 +676,12 @@ public class FMLClientHandler implements IFMLSidedHandler
             if ("FML".equals(extendedData.type) && extendedData.isCompatible)
             {
                 idx = 0;
-                tooltip = String.format("Compatible FML modded server\n%d mods present", extendedData.modCount);
+                tooltip = String.format("Compatible FML modded server\n%d mods present", extendedData.modData.size());
             }
             else if ("FML".equals(extendedData.type) && !extendedData.isCompatible)
             {
                 idx = 16;
-                tooltip = String.format("Incompatible FML modded server\n%d mods present", extendedData.modCount);
+                tooltip = String.format("Incompatible FML modded server\n%d mods present", extendedData.modData.size());
             }
             else if ("BUKKIT".equals(extendedData.type))
             {

fml/src/main/java/cpw/mods/fml/client/GuiBackupFailed.java

@@ -0,0 +1,55 @@
+/*
+ * Forge Mod Loader
+ * Copyright (c) 2012-2013 cpw.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Lesser Public License v2.1
+ * which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
+ *
+ * Contributors:
+ *     cpw - implementation
+ */
+
+package cpw.mods.fml.client;
+
+import java.io.File;
+import net.minecraft.client.gui.GuiButton;
+import net.minecraft.client.gui.GuiScreen;
+import net.minecraft.client.resources.I18n;
+
+public class GuiBackupFailed extends GuiScreen
+{
+    private GuiScreen parent;
+    private File zipName;
+    public GuiBackupFailed(GuiScreen parent, File zipName)
+    {
+        this.parent = parent;
+        this.zipName = zipName;
+    }
+
+    @SuppressWarnings("unchecked")
+    @Override
+    public void func_73866_w_()
+    {
+        this.field_146292_n.add(new GuiButton(1, this.field_146294_l / 2 - 75, this.field_146295_m - 38, I18n.func_135052_a("gui.done")));
+    }
+
+    @Override
+    protected void func_146284_a(GuiButton p_73875_1_)
+    {
+        if (p_73875_1_.field_146124_l && p_73875_1_.field_146127_k == 1)
+        {
+            FMLClientHandler.instance().showGuiScreen(parent);
+        }
+    }
+    @Override
+    public void func_73863_a(int p_73863_1_, int p_73863_2_, float p_73863_3_)
+    {
+        this.func_146276_q_();
+        int offset = Math.max(85 - 2 * 10, 10);
+        this.func_73732_a(this.field_146289_q, String.format("There was an error saving the archive %s", zipName.getName()), this.field_146294_l / 2, offset, 0xFFFFFF);
+        offset += 10;
+        this.func_73732_a(this.field_146289_q, String.format("Please fix the problem and try again"), this.field_146294_l / 2, offset, 0xFFFFFF);
+        super.func_73863_a(p_73863_1_, p_73863_2_, p_73863_3_);
+    }
+}

fml/src/main/java/cpw/mods/fml/client/GuiOldSaveLoadConfirm.java

@@ -0,0 +1,73 @@
+package cpw.mods.fml.client;
+
+import java.io.File;
+import java.io.IOException;
+import net.minecraft.client.gui.GuiButton;
+import net.minecraft.client.gui.GuiLabel;
+import net.minecraft.client.gui.GuiScreen;
+import net.minecraft.client.gui.GuiSelectWorld;
+import net.minecraft.client.gui.GuiYesNo;
+import org.apache.logging.log4j.Level;
+import cpw.mods.fml.common.FMLLog;
+import cpw.mods.fml.common.ObfuscationReflectionHelper;
+import cpw.mods.fml.common.ZipperUtil;
+
+public class GuiOldSaveLoadConfirm extends GuiYesNo {
+
+    private String dirName;
+    private String saveName;
+    private File zip;
+    public GuiOldSaveLoadConfirm(String dirName, String saveName, GuiScreen parent)
+    {
+        super(parent, "", "", 0);
+        this.dirName = dirName;
+        this.saveName = saveName;
+        this.zip = new File(FMLClientHandler.instance().getClient().field_71412_D,String.format("%s-%2$td%2$tm%2$ty%2$tH%2$tM%2$tS.zip", saveName, System.currentTimeMillis()));
+    }
+    @Override
+    public void func_73863_a(int p_73863_1_, int p_73863_2_, float p_73863_3_)
+    {
+        this.func_146276_q_();
+        this.func_73732_a(this.field_146289_q, String.format("The world %s contains pre-update modding data", saveName), this.field_146294_l / 2, 50, 16777215);
+        this.func_73732_a(this.field_146289_q, String.format("There may be problems updating it to this version"), this.field_146294_l / 2, 70, 16777215);
+        this.func_73732_a(this.field_146289_q, String.format("FML will save a zip to %s", zip.getName()), this.field_146294_l / 2, 90, 16777215);
+        this.func_73732_a(this.field_146289_q, String.format("Do you wish to continue loading?"), this.field_146294_l / 2, 110, 16777215);
+        int k;
+
+        for (k = 0; k < this.field_146292_n.size(); ++k)
+        {
+            ((GuiButton)this.field_146292_n.get(k)).func_146112_a(this.field_146297_k, p_73863_1_, p_73863_2_);
+        }
+
+        for (k = 0; k < this.field_146293_o.size(); ++k)
+        {
+            ((GuiLabel)this.field_146293_o.get(k)).func_146159_a(this.field_146297_k, p_73863_1_, p_73863_2_);
+        }
+    }
+    @Override
+    protected void func_146284_a(GuiButton p_146284_1_)
+    {
+        if (p_146284_1_.field_146127_k == 1)
+        {
+            ObfuscationReflectionHelper.setPrivateValue(GuiSelectWorld.class, (GuiSelectWorld)field_146355_a, false, "field_"+"146634_i");
+            FMLClientHandler.instance().showGuiScreen(field_146355_a);
+        }
+        else
+        {
+            FMLLog.info("Capturing current state of world %s into file %s", saveName, zip.getAbsolutePath());
+            try
+            {
+                ZipperUtil.zip(new File(FMLClientHandler.instance().getSavesDir(), dirName), zip);
+            } catch (IOException e)
+            {
+                FMLLog.log(Level.WARN, e, "There was a problem saving the backup %s. Please fix and try again", zip.getName());
+                FMLClientHandler.instance().showGuiScreen(new GuiBackupFailed(field_146355_a, zip));
+                return;
+            }
+            FMLClientHandler.instance().showGuiScreen(null);
+            FMLClientHandler.instance().launchIntegratedServerCallback(dirName, saveName);
+        }
+
+    }
+
+}

fml/src/main/java/cpw/mods/fml/common/FMLCommonHandler.java

@@ -371,7 +371,7 @@ public class FMLCommonHandler
         }
         handlerSet.add(handler);
         Map<String,NBTBase> additionalProperties = Maps.newHashMap();
-//        worldInfo.setAdditionalProperties(additionalProperties);
+        worldInfo.setAdditionalProperties(additionalProperties);
         for (ModContainer mc : Loader.instance().getModList())
         {
             if (mc instanceof InjectedModContainer)

fml/src/main/java/cpw/mods/fml/common/ZipperUtil.java

@@ -0,0 +1,58 @@
+package cpw.mods.fml.common;
+
+import java.io.Closeable;
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.URI;
+import java.util.Deque;
+import java.util.LinkedList;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
+import com.google.common.io.Files;
+
+/**
+ * Copied from http://stackoverflow.com/questions/1399126/java-util-zip-recreating-directory-structure
+ * because the code looked very tidy and neat. Thanks, McDowell!
+ *
+ * @author McDowell
+ *
+ */
+public class ZipperUtil {
+    public static void zip(File directory, File zipfile) throws IOException
+    {
+        URI base = directory.toURI();
+        Deque<File> queue = new LinkedList<File>();
+        queue.push(directory);
+        OutputStream out = new FileOutputStream(zipfile);
+        Closeable res = null;
+        try
+        {
+            ZipOutputStream zout = new ZipOutputStream(out);
+            res = zout;
+            while (!queue.isEmpty())
+            {
+                directory = queue.pop();
+                for (File kid : directory.listFiles())
+                {
+                    String name = base.relativize(kid.toURI()).getPath();
+                    if (kid.isDirectory())
+                    {
+                        queue.push(kid);
+                        name = name.endsWith("/") ? name : name + "/";
+                        zout.putNextEntry(new ZipEntry(name));
+                    } else
+                    {
+                        zout.putNextEntry(new ZipEntry(name));
+                        Files.copy(kid, zout);
+                        zout.closeEntry();
+                    }
+                }
+            }
+        } finally
+        {
+            res.close();
+        }
+    }
+}