Some tweaks around the code base. A functional consumer for networking - return a bool from your consumer function, rather than setPacketHandled.

Tweak the server modloading behaviour to try and be a bit clearer that a mod errored.

Signed-off-by: cpw <cpw+github@weeksfamily.ca>

src/fmllauncher/java/net/minecraftforge/fml/loading/Java9BackportUtils.java

@@ -19,7 +19,9 @@
 
 package net.minecraftforge.fml.loading;
 
+import java.util.Optional;
 import java.util.function.BiConsumer;
+import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.stream.Collector;
 import java.util.stream.Stream;
@@ -40,4 +42,12 @@ public class Java9BackportUtils
                 downstream.combiner(), downstream.finisher(),
                 downstream.characteristics().toArray(new Collector.Characteristics[0]));
     }
+
+    public static <T> void ifPresentOrElse(Optional<T> optional, Consumer<? super T> action, Runnable emptyAction) {
+        if (optional.isPresent()) {
+            action.accept(optional.get());
+        } else {
+            emptyAction.run();
+        }
+    }
 }

src/fmllauncher/java/net/minecraftforge/fml/loading/ModSorter.java

@@ -144,20 +144,31 @@ public class ModSorter
 
     private void buildUniqueList()
     {
-        final Stream<ModInfo> modInfos = modFiles.stream().map(ModFile::getModInfos).flatMap(Collection::stream).map(ModInfo.class::cast);
+        final Stream<ModInfo> modInfos = modFiles.stream()
+                .map(ModFile::getModInfos)
+                .flatMap(Collection::stream)
+                .map(ModInfo.class::cast);
         final Map<String, List<ModInfo>> modIds = modInfos.collect(Collectors.groupingBy(IModInfo::getModId));
 
         // TODO: make this figure out dupe handling better
-        final List<Map.Entry<String, List<ModInfo>>> dupedMods = modIds.entrySet().stream().filter(e -> e.getValue().size() > 1).collect(Collectors.toList());
+        final List<Map.Entry<String, List<ModInfo>>> dupedMods = modIds
+                .entrySet()
+                .stream()
+                .filter(e -> e.getValue().size() > 1)
+                .collect(Collectors.toList());
 
         if (!dupedMods.isEmpty()) {
-            final List<EarlyLoadingException.ExceptionData> duplicateModErrors = dupedMods.stream().
-                    map(dm -> new EarlyLoadingException.ExceptionData("fml.modloading.dupedmod", dm.getValue().get(0))).
-                    collect(Collectors.toList());
+            final List<EarlyLoadingException.ExceptionData> duplicateModErrors = dupedMods
+                    .stream()
+                    .map(dm -> new EarlyLoadingException.ExceptionData("fml.modloading.dupedmod", dm.getValue().get(0)))
+                    .collect(Collectors.toList());
             throw new EarlyLoadingException("Duplicate mods found", null,  duplicateModErrors);
         }
 
-        modIdNameLookup = modIds.entrySet().stream().collect(Collectors.toMap(Map.Entry::getKey, e -> e.getValue().get(0)));
+        modIdNameLookup = modIds
+                .entrySet()
+                .stream()
+                .collect(Collectors.toMap(Map.Entry::getKey, e -> e.getValue().get(0)));
     }
 
     private void verifyDependencyVersions()

src/fmllauncher/java/net/minecraftforge/fml/loading/moddiscovery/Scanner.java

@@ -45,8 +45,10 @@ public class Scanner {
         result.addModFileInfo(fileToScan.getModFileInfo());
         fileToScan.scanFile(p -> fileVisitor(p, result));
         final IModLanguageProvider loader = fileToScan.getLoader();
-        LOGGER.debug(SCAN, "Scanning {} with language loader {}", fileToScan.getFilePath(), loader.name());
-        loader.getFileVisitor().accept(result);
+        if (loader != null) {
+            LOGGER.debug(SCAN, "Scanning {} with language loader {}", fileToScan.getFilePath(), loader.name());
+            loader.getFileVisitor().accept(result);
+        }
         return result;
     }
 

src/main/java/net/minecraftforge/common/DimensionManager.java

@@ -60,6 +60,7 @@ import net.minecraft.world.dimension.DimensionType;
 import net.minecraftforge.event.world.RegisterDimensionsEvent;
 import net.minecraftforge.event.world.WorldEvent;
 import net.minecraftforge.fml.StartupQuery;
+import net.minecraftforge.fml.server.ServerModLoader;
 import net.minecraftforge.registries.ClearableRegistry;
 import net.minecraftforge.registries.ForgeRegistries;
 
@@ -160,6 +161,9 @@ public class DimensionManager
         Validate.notNull(server, "Must provide server when creating world");
         Validate.notNull(dim, "Dimension type must not be null");
 
+        if (ServerModLoader.hasErrors()) {
+            throw new RuntimeException("The server has failed to initialize correctly due to mod loading errors. Examine the crash report for more details.");
+        }
         // If we're in the early stages of loading, we need to return null so CommandSource can work properly for command function
         if (StartupQuery.pendingQuery()) {
             return null;

src/main/java/net/minecraftforge/fml/LoadingFailedException.java

@@ -20,6 +20,7 @@
 package net.minecraftforge.fml;
 
 import java.util.List;
+import java.util.stream.Collectors;
 
 public class LoadingFailedException extends RuntimeException {
     private final List<ModLoadingException> loadingExceptions;
@@ -31,4 +32,9 @@ public class LoadingFailedException extends RuntimeException {
     public List<ModLoadingException> getErrors() {
         return this.loadingExceptions;
     }
+
+    @Override
+    public String getMessage() {
+        return "Loading errors encountered: " + this.loadingExceptions.stream().map(ModLoadingException::getMessage).collect(Collectors.joining(",\n\t", "[\n\t", "\n]"));
+    }
 }

src/main/java/net/minecraftforge/fml/network/simple/SimpleChannel.java

@@ -182,6 +182,23 @@ public class SimpleChannel
             return this;
         }
 
+        public interface ToBooleanBiFunction<T, U> {
+            boolean applyAsBool(T first, U second);
+        }
+
+        /**
+         * Function returning a boolean "packet handled" indication, for simpler channel building.
+         * @param handler a handler
+         * @return this
+         */
+        public MessageBuilder<MSG> consumer(ToBooleanBiFunction<MSG, Supplier<NetworkEvent.Context>> handler) {
+            this.consumer = (msg, ctx) -> {
+                boolean handled = handler.applyAsBool(msg, ctx);
+                ctx.get().setPacketHandled(handled);
+            };
+            return this;
+        }
+
         public void add() {
             final IndexedMessageCodec.MessageHandler<MSG> message = this.channel.registerMessage(this.id, this.type, this.encoder, this.decoder, this.consumer);
             if (this.loginIndexSetter != null) {

src/main/java/net/minecraftforge/fml/server/ServerModLoader.java

@@ -21,10 +21,7 @@ package net.minecraftforge.fml.server;
 
 import net.minecraft.server.dedicated.DedicatedServer;
 import net.minecraftforge.common.MinecraftForge;
-import net.minecraftforge.fml.LogicalSidedProvider;
-import net.minecraftforge.fml.ModLoader;
-import net.minecraftforge.fml.ModLoadingWarning;
-import net.minecraftforge.fml.SidedProvider;
+import net.minecraftforge.fml.*;
 import net.minecraftforge.fml.network.FMLStatusPing;
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
@@ -37,17 +34,31 @@ public class ServerModLoader
 {
     private static final Logger LOGGER = LogManager.getLogger();
     private static DedicatedServer server;
+    private static boolean hasErrors = false;
+
     public static void begin(DedicatedServer dedicatedServer) {
         ServerModLoader.server = dedicatedServer;
         SidedProvider.setServer(()->dedicatedServer);
         LogicalSidedProvider.setServer(()->dedicatedServer);
         LanguageHook.loadForgeAndMCLangs();
-        ModLoader.get().gatherAndInitializeMods(null);
-        ModLoader.get().loadMods(Runnable::run, (a)->{}, (a)->{});
+        try {
+            ModLoader.get().gatherAndInitializeMods(null);
+            ModLoader.get().loadMods(Runnable::run, (a)->{}, (a)->{});
+        } catch (LoadingFailedException e) {
+            ServerModLoader.hasErrors = true;
+            throw e;
+        }
     }
 
+
     public static void end() {
-        ModLoader.get().finishMods(Runnable::run);
+        try {
+            ModLoader.get().finishMods(Runnable::run);
+        } catch (LoadingFailedException e) {
+            ServerModLoader.hasErrors = true;
+            throw e;
+
+        }
         List<ModLoadingWarning> warnings = ModLoader.get().getWarnings();
         if (!warnings.isEmpty()) {
             LOGGER.warn(LOADING, "Mods loaded with {} warnings", warnings.size());
@@ -56,4 +67,8 @@ public class ServerModLoader
         MinecraftForge.EVENT_BUS.start();
         server.getServerStatusResponse().setForgeData(new FMLStatusPing()); //gathers NetworkRegistry data
     }
+
+    public static boolean hasErrors() {
+        return ServerModLoader.hasErrors;
+    }
 }