Add fix or 1.12.2 SIDE issue

Author: LexManos

src/main/java/net/minecraftforge/mcmaven/impl/repo/mcpconfig/MCPSide.java

@@ -6,6 +6,7 @@
 
 import net.minecraftforge.mcmaven.impl.repo.mcpconfig.MinecraftTasks.ArtifactFile;
 import net.minecraftforge.mcmaven.impl.util.Artifact;
+import net.minecraftforge.mcmaven.impl.util.StupidHacks;
 import net.minecraftforge.mcmaven.impl.util.Task;
 
 import org.jetbrains.annotations.Nullable;
@@ -93,7 +94,7 @@ public List<Artifact> getMCPConfigLibraries() {
         var artifacts = new ArrayList<Artifact>();
 
         for (var lib : this.mcp.getConfig().getLibraries(this.side)) {
-            var artifact = Artifact.from(lib);
+            var artifact = StupidHacks.fixLegacyTools(Artifact.from(lib));
             artifacts.add(artifact);
         }
 

src/main/java/net/minecraftforge/mcmaven/impl/repo/mcpconfig/MCPTaskFactory.java

@@ -47,6 +47,7 @@
 import net.minecraftforge.util.file.FileUtils;
 import net.minecraftforge.util.hash.HashStore;
 import net.minecraftforge.mcmaven.impl.util.ProcessUtils;
+import net.minecraftforge.mcmaven.impl.util.StupidHacks;
 import net.minecraftforge.mcmaven.impl.util.Task;
 import net.minecraftforge.mcmaven.impl.util.Util;
 import net.minecraftforge.srgutils.IMappingFile;
@@ -838,7 +839,7 @@ private static final boolean isDecompiler(String name, Artifact artifact) {
     private File execute(String name, List<TaskOrArg> jvmArgs, List<TaskOrArg> runArgs, MCPConfig.Function func, File log, File output) {
         // First download the tool
         var maven = new MavenCache("mcp-tools", func.repo, this.side.getMCP().getCache().root());
-        var toolA = Artifact.from(func.version);
+        var toolA = StupidHacks.fixLegacyTools(Artifact.from(func.version));
         var tool = maven.download(toolA);
 
         var isDecompile = isDecompiler(name, toolA);

src/main/java/net/minecraftforge/mcmaven/impl/util/StupidHacks.java

@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) Forge Development LLC and contributors
+ * SPDX-License-Identifier: LGPL-2.1-only
+ */
+package net.minecraftforge.mcmaven.impl.util;
+
+/*
+ * Here be stupid hacks that help us support old versions,
+ * I've decided to stick them all in one place so we can just call
+ * a magic function and never have to actually look at these abominations.
+ */
+public class StupidHacks {
+
+    public static Artifact fixLegacyTools(Artifact artifact) {
+        // Some MCPConfig versions reference a merge tool that has an invlaid 'BUKKIT' side.
+        // This was fixed in 0.2.3.3 https://github.com/MinecraftForge/MergeTool/commit/e68e1b06ba87c68bc1a5c922395286b53a17dddf
+        if ("net.minecraftforge".equals(artifact.getGroup()) && "mergetool".equals(artifact.getName()) && "0.2.3.2".equals(artifact.getVersion()))
+            return artifact.withVersion("0.2.3.3");
+        return artifact;
+    }
+
+}