Enhance output of common FML errors in crash reports and server GUI.

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

@@ -14,6 +14,7 @@ package cpw.mods.fml.client;
 
 import net.minecraft.client.gui.FontRenderer;
 import net.minecraft.client.gui.GuiErrorScreen;
+import cpw.mods.fml.common.EnhancedRuntimeException;
 import cpw.mods.fml.common.IFMLHandledException;
 import cpw.mods.fml.relauncher.Side;
 import cpw.mods.fml.relauncher.SideOnly;
@@ -29,16 +30,16 @@ import cpw.mods.fml.relauncher.SideOnly;
  *
  */
 @SideOnly(Side.CLIENT)
-public abstract class CustomModLoadingErrorDisplayException extends RuntimeException implements IFMLHandledException
+public abstract class CustomModLoadingErrorDisplayException extends EnhancedRuntimeException implements IFMLHandledException
 {
     public CustomModLoadingErrorDisplayException() {
     }
-    
+
     public CustomModLoadingErrorDisplayException(String message, Throwable cause)
     {
         super(message, cause);
     }
-    
+
     private static final long serialVersionUID = 1L;
 
     /**
@@ -62,4 +63,6 @@ public abstract class CustomModLoadingErrorDisplayException extends RuntimeExcep
      * @param tickTime tick time
      */
     public abstract void drawScreen(GuiErrorScreen errorScreen, FontRenderer fontRenderer, int mouseRelX, int mouseRelY, float tickTime);
+
+    @Override public void printStackTrace(EnhancedRuntimeException.WrappedPrintStream s){}; // Do Nothing unless the modder wants to.
 }

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

@@ -13,6 +13,9 @@
 package cpw.mods.fml.common;
 
 import java.io.File;
+import java.util.Map.Entry;
+
+import cpw.mods.fml.common.EnhancedRuntimeException.WrappedPrintStream;
 
 import com.google.common.collect.SetMultimap;
 
@@ -24,4 +27,14 @@ public class DuplicateModsFoundException extends LoaderException {
 		this.dupes = dupes;
 	}
 
+    @Override
+    protected void printStackTrace(WrappedPrintStream stream)
+    {
+        stream.println("Duplicate Mods:");
+        for (Entry<ModContainer, File> e : dupes.entries())
+        {
+            stream.println(String.format("\t%s : %s", e.getKey().getModId(), e.getValue().getAbsolutePath()));
+        }
+        stream.println("");
+    }
 }

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

@@ -0,0 +1,92 @@
+/*
+ * Forge Mod Loader
+ * Copyright (c) 2012-2016 Forge Dev LLC.
+ * 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
+ */
+package cpw.mods.fml.common;
+
+import java.io.PrintStream;
+import java.io.PrintWriter;
+import java.io.StringWriter;
+
+/**
+ * RuntimeException that gives subclasses the simple opportunity to write extra data when printing the stack trace.
+ * Mainly a helper class as printsStackTrace has multiple signatures.
+ */
+public abstract class EnhancedRuntimeException extends RuntimeException
+{
+    private static final long serialVersionUID = 1L;
+
+    public EnhancedRuntimeException() { super(); }
+    public EnhancedRuntimeException(String message) { super(message); }
+    public EnhancedRuntimeException(String message, Throwable cause) { super(message, cause); }
+    public EnhancedRuntimeException(Throwable cause) { super(cause); }
+    protected EnhancedRuntimeException(String message, Throwable cause, boolean enableSuppression, boolean writableStackTrace) {
+        super(message, cause, enableSuppression, writableStackTrace);
+    }
+
+    @Override
+    public String getMessage()
+    {
+        StackTraceElement[] stack = Thread.currentThread().getStackTrace();
+        if (stack.length > 2 && stack[2].getClassName().startsWith("org.apache.logging.log4j."))
+        {
+            // This is a bit of a hack to force ourselves to be able to give a extended description when log4j prints this out.
+            // Sadly this text is displayed AFTER the initial exception line, and before the stack trace. But as the intention
+            // is to print this to the end user this is what we need to do.
+            final StringWriter buf = new StringWriter();
+
+            String msg = super.getMessage();
+            if (msg != null)
+                buf.append(msg);
+
+            buf.append('\n');
+            this.printStackTrace(new WrappedPrintStream()
+            {
+                @Override
+                void println(String line)
+                {
+                    buf.append(line).append('\n');
+                }
+            });
+            return buf.toString();
+        }
+        return super.getMessage();
+    }
+
+    @Override
+    public void printStackTrace(final PrintWriter s)
+    {
+        printStackTrace(new WrappedPrintStream()
+        {
+            @Override
+            void println(String line)
+            {
+                s.println(line);
+            }
+        });
+        super.printStackTrace(s);
+    }
+    public void printStackTrace(final PrintStream s)
+    {
+        printStackTrace(new WrappedPrintStream()
+        {
+            @Override
+            void println(String line)
+            {
+                s.println(line);
+            }
+        });
+        super.printStackTrace(s);
+    }
+
+    protected abstract void printStackTrace(WrappedPrintStream stream);
+
+    public static abstract class WrappedPrintStream
+    {
+        abstract void println(String line);
+    }
+}

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

@@ -96,7 +96,7 @@ public interface ILanguageAdapter {
 
             // If we come here we could not find a setter for this proxy.
             FMLLog.severe("Failed loading proxy into %s.%s, could not find setter function. Did you declare the field with 'val' instead of 'var'?", proxyTarget.getSimpleName(), target.getName());
-            throw new LoaderException();
+            throw new LoaderException(String.format("Failed loading proxy into %s.%s, could not find setter function. Did you declare the field with 'val' instead of 'var'?", proxyTarget.getSimpleName(), target.getName()));
         }
 
         @Override
@@ -141,7 +141,7 @@ public interface ILanguageAdapter {
                             if (!target.getType().isAssignableFrom(proxy.getClass()))
                             {
                                 FMLLog.severe("Attempted to load a proxy type %s into %s.%s, but the types don't match", targetType, proxyTarget.getSimpleName(), target.getName());
-                                throw new LoaderException();
+                                throw new LoaderException(String.format("Attempted to load a proxy type %s into %s.%s, but the types don't match", targetType, proxyTarget.getSimpleName(), target.getName()));
                             }
 
                             setProxy(target, proxyTarget, proxy);

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

@@ -182,7 +182,7 @@ public class Loader
         if (!mccversion.equals(MC_VERSION))
         {
             FMLLog.severe("This version of FML is built for Minecraft %s, we have detected Minecraft %s in your minecraft jar file", mccversion, MC_VERSION);
-            throw new LoaderException();
+            throw new LoaderException(String.format("This version of FML is built for Minecraft %s, we have detected Minecraft %s in your minecraft jar file", mccversion, MC_VERSION));
         }
 
         minecraft = new MinecraftDummyContainer(MC_VERSION);
@@ -418,7 +418,7 @@ public class Loader
             if (!dirMade)
             {
                 FMLLog.severe("Unable to create the mod directory %s", canonicalModsPath);
-                throw new LoaderException();
+                throw new LoaderException(String.format("Unable to create the mod directory %s", canonicalModsPath));
             }
             FMLLog.info("Mod directory created successfully");
         }
@@ -676,7 +676,7 @@ public class Loader
         if (parseFailure)
         {
             FMLLog.log(Level.WARN, "Unable to parse dependency string %s", dependencyString);
-            throw new LoaderException();
+            throw new LoaderException(String.format("Unable to parse dependency string %s", dependencyString));
         }
     }
 

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

@@ -5,14 +5,14 @@
  * 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.common;
 
-public class LoaderException extends RuntimeException
+public class LoaderException extends EnhancedRuntimeException
 {
     /**
      *
@@ -27,4 +27,10 @@ public class LoaderException extends RuntimeException
     public LoaderException()
     {
     }
+    public LoaderException(String message)
+    {
+        super(message);
+    }
+
+    @Override protected void printStackTrace(WrappedPrintStream stream){}
 }

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

@@ -16,7 +16,7 @@ import java.util.Set;
 
 import cpw.mods.fml.common.versioning.ArtifactVersion;
 
-public class MissingModsException extends RuntimeException
+public class MissingModsException extends EnhancedRuntimeException
 {
     private static final long serialVersionUID = 1L;
     public final Set<ArtifactVersion> missingMods;
@@ -25,4 +25,15 @@ public class MissingModsException extends RuntimeException
     {
         this.missingMods = missingMods;
     }
+
+    @Override
+    protected void printStackTrace(WrappedPrintStream stream)
+    {
+        stream.println("Missing Mods:");
+        for (ArtifactVersion v : missingMods)
+        {
+            stream.println(String.format("\t%s : %s", v.getLabel(), v.getRangeString()));
+        }
+        stream.println("");
+    }
 }

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

@@ -45,7 +45,7 @@ public class ProxyInjector
                 {
                     // Impossible?
                     FMLLog.severe("Attempted to load a proxy type into %s.%s but the field was not found", targ.getClassName(), targ.getObjectName());
-                    throw new LoaderException();
+                    throw new LoaderException(String.format("Attempted to load a proxy type into %s.%s but the field was not found", targ.getClassName(), targ.getObjectName()));
                 }
                 target.setAccessible(true);
 
@@ -61,12 +61,12 @@ public class ProxyInjector
                 if (languageAdapter.supportsStatics() && (target.getModifiers() & Modifier.STATIC) == 0 )
                 {
                     FMLLog.severe("Attempted to load a proxy type %s into %s.%s, but the field is not static", targetType, targ.getClassName(), targ.getObjectName());
-                    throw new LoaderException();
+                    throw new LoaderException(String.format("Attempted to load a proxy type %s into %s.%s, but the field is not static", targetType, targ.getClassName(), targ.getObjectName()));
                 }
                 if (!target.getType().isAssignableFrom(proxy.getClass()))
                 {
                     FMLLog.severe("Attempted to load a proxy type %s into %s.%s, but the types don't match", targetType, targ.getClassName(), targ.getObjectName());
-                    throw new LoaderException();
+                    throw new LoaderException(String.format("Attempted to load a proxy type %s into %s.%s, but the types don't match", targetType, targ.getClassName(), targ.getObjectName()));
                 }
                 languageAdapter.setProxy(target, proxyTarget, proxy);
             }

fml/src/main/java/cpw/mods/fml/common/network/internal/EntitySpawnHandler.java

@@ -59,6 +59,11 @@ public class EntitySpawnHandler extends SimpleChannelInboundHandler<FMLMessage.E
     {
         ModContainer mc = Loader.instance().getIndexedModList().get(spawnMsg.modId);
         EntityRegistration er = EntityRegistry.instance().lookupModSpawn(mc, spawnMsg.modEntityTypeId);
+        if (er == null)
+        {
+            throw new RuntimeException( "Could not spawn mod entity ModID: " + spawnMsg.modId + " EntityID: " + spawnMsg.modEntityTypeId +
+                    " at ( " + spawnMsg.scaledX + "," + spawnMsg.scaledY + ", " + spawnMsg.scaledZ + ") Please contact mod author or server admin.");
+        }
         WorldClient wc = FMLClientHandler.instance().getWorldClient();
         Class<? extends Entity> cls = er.getEntityClass();
         try
@@ -117,7 +122,7 @@ public class EntitySpawnHandler extends SimpleChannelInboundHandler<FMLMessage.E
             wc.addEntityToWorld(spawnMsg.entityId, entity);
         } catch (Exception e)
         {
-            FMLLog.log(Level.ERROR, e, "A severe problem occurred during the spawning of an entity");
+            FMLLog.log(Level.ERROR, e, "A severe problem occurred during the spawning of an entity at ( " + spawnMsg.scaledX + "," + spawnMsg.scaledY + ", " + spawnMsg.scaledZ +")");
             throw Throwables.propagate(e);
         }
     }

fml/src/main/java/cpw/mods/fml/common/registry/IncompatibleSubstitutionException.java

@@ -3,6 +3,7 @@ package cpw.mods.fml.common.registry;
 public class IncompatibleSubstitutionException extends RuntimeException {
     public IncompatibleSubstitutionException(String fromName, Object replacement, Object original)
     {
+        super(String.format("The substitute %s for %s (type %s) is type incompatible.", replacement.getClass().getName(), fromName, original.getClass().getName()));
     }
 
     private static final long serialVersionUID = 1L;