Split userdev data entry point into it's own provider to fix duplicate mod issue.

build.gradle

@@ -335,6 +335,14 @@ project(':forge') {
                 'Implementation-Title':     'FML Launcher',
                 'Implementation-Version':   SPEC_VERSION,
                 'Implementation-Vendor':    'Forge'
+            ] as LinkedHashMap,
+            'net/minecraftforge/fml/userdev/': [
+                'Specification-Title':      'Forge User Development',
+                'Specification-Vendor':     'Forge Development LLC',
+                'Specification-Version':    SPEC_VERSION,
+                'Implementation-Title':     project.group,
+                'Implementation-Version':   project.version.substring(MC_VERSION.length() + 1),
+                'Implementation-Vendor':    'Forge Development LLC'
             ] as LinkedHashMap
         ]
     }
@@ -881,7 +889,7 @@ project(':forge') {
             data {
                 main 'net.minecraftforge.userdev.LaunchTesting'
 
-                environment 'target', 'fmldevdata'
+                environment 'target', 'fmluserdevdata'
 
                 environment 'MC_VERSION', "${MC_VERSION}"
                 environment 'FORGE_GROUP', "${project.group}"

mdk/build.gradle

@@ -64,6 +64,24 @@ minecraft {
                 }
             }
         }
+
+        data {
+            workingDirectory project.file('run')
+
+            // Recommended logging data for a userdev environment
+            property 'forge.logging.markers', 'SCAN,REGISTRIES,REGISTRYDUMP'
+
+            // Recommended logging level for the console
+            property 'forge.logging.console.level', 'debug'
+
+            args '--mod', 'examplemod', '--all', '--output', file('src/generated/resources/')
+
+            mods {
+                examplemod {
+                    source sourceSets.main
+                }
+            }
+        }
     }
 }
 

mdk/src/main/resources/META-INF/mods.toml

@@ -42,7 +42,7 @@ Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed mollis lacinia magn
     # Does this dependency have to exist - if not, ordering below must be specified
     mandatory=true #mandatory
     # The version range of the dependency
-    versionRange="[26,)" #mandatory
+    versionRange="[27,)" #mandatory
     # An ordering relationship for the dependency - BEFORE or AFTER required if the relationship is not mandatory
     ordering="NONE"
     # Side this dependency is applied on - BOTH, CLIENT or SERVER
@@ -51,6 +51,6 @@ Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed mollis lacinia magn
 [[dependencies.examplemod]]
     modId="minecraft"
     mandatory=true
-    versionRange="[1.14.2]"
+    versionRange="[1.14.3]"
     ordering="NONE"
     side="BOTH"

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

@@ -52,6 +52,7 @@ public class ExplodedDirectoryLocator implements IModLocator {
             Path resources = pathPathPair.getLeft();
             Path modtoml = resources.resolve(modstoml);
             if (Files.exists(modtoml)) {
+                LOGGER.debug(LOADING, "Found exploded directory mod manifest at {}", modtoml.toString());
                 ModFile mf = new ModFile(pathPathPair.getLeft(), this);
                 mods.put(mf, pathPathPair);
             } else {

src/userdev/java/net/minecraftforge/userdev/ClasspathLocator.java

@@ -67,6 +67,7 @@ public class ClasspathLocator extends AbstractJarFileLocator {
                 if (Files.isDirectory(path))
                     continue;
 
+                LOGGER.debug(CORE, "Found classpath mod: {}", path);
                 this.modCoords.add(path);
             }
         } catch (IOException e) {

src/userdev/java/net/minecraftforge/userdev/FMLUserdevDataLaunchProvider.java

@@ -0,0 +1,61 @@
+/*
+ * Minecraft Forge
+ * Copyright (c) 2016-2019.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation version 2.1
+ * of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+package net.minecraftforge.userdev;
+
+import cpw.mods.modlauncher.api.ILaunchHandlerService;
+import cpw.mods.modlauncher.api.ITransformingClassLoader;
+import net.minecraftforge.api.distmarker.Dist;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+import java.util.concurrent.Callable;
+
+import static net.minecraftforge.fml.loading.LogMarkers.CORE;
+
+public class FMLUserdevDataLaunchProvider extends FMLUserdevLaunchProvider implements ILaunchHandlerService
+{
+    private static final Logger LOGGER = LogManager.getLogger();
+
+    @Override
+    public String name()
+    {
+        return "fmluserdevdata";
+    }
+
+    @Override
+    public Callable<Void> launchService(String[] arguments, ITransformingClassLoader launchClassLoader)
+    {
+        return () -> {
+            LOGGER.debug(CORE, "Launching minecraft in {} with arguments {}", launchClassLoader, arguments);
+            super.beforeStart(launchClassLoader);
+            launchClassLoader.addTargetPackageFilter(getPackagePredicate());
+            Thread.currentThread().setContextClassLoader(launchClassLoader.getInstance());
+            Class.forName("net.minecraft.data.Main", true, launchClassLoader.getInstance()).getMethod("main", String[].class).invoke(null, (Object)arguments);
+            return null;
+        };
+    }
+
+    @Override
+    public Dist getDist()
+    {
+        return Dist.CLIENT;
+    }
+}

src/userdev/resources/META-INF/services/cpw.mods.modlauncher.api.ILaunchHandlerService

@@ -1,5 +1,6 @@
 net.minecraftforge.userdev.FMLUserdevClientLaunchProvider
 net.minecraftforge.userdev.FMLUserdevServerLaunchProvider
+net.minecraftforge.userdev.FMLUserdevDataLaunchProvider
 net.minecraftforge.userdev.FMLDevClientLaunchProvider
 net.minecraftforge.userdev.FMLDevServerLaunchProvider
 net.minecraftforge.userdev.FMLDevDataLaunchProvider