From b1ed6a46068f867f86dc7d637fb21d76aafeeed0 Mon Sep 17 00:00:00 2001
From: Juuz <6596629+Juuxel@users.noreply.github.com>
Date: Mon, 1 Jul 2024 23:39:33 +0300
Subject: [PATCH] MappingConfiguration: Remove optimised merged v2 code path

This was leaving the broken "intermediary, named, official"
namespace order from layered mappings. While it could've been
fixed there, the optimised code path also lacked some fixes
to enclosing classes from MappingsMerger, so it's better to
use the "vanilla" code from Fabric.
---
 .../mappings/MappingConfiguration.java        | 23 +++----------------
 1 file changed, 3 insertions(+), 20 deletions(-)

diff --git a/src/main/java/net/fabricmc/loom/configuration/providers/mappings/MappingConfiguration.java b/src/main/java/net/fabricmc/loom/configuration/providers/mappings/MappingConfiguration.java
index 2a256b30..2e52b85b 100644
--- a/src/main/java/net/fabricmc/loom/configuration/providers/mappings/MappingConfiguration.java
+++ b/src/main/java/net/fabricmc/loom/configuration/providers/mappings/MappingConfiguration.java
@@ -37,16 +37,15 @@ import java.nio.file.Path;
 import java.nio.file.StandardCopyOption;
 import java.nio.file.StandardOpenOption;
 import java.util.ArrayList;
-import java.util.Arrays;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 
-import org.apache.tools.ant.util.StringUtils;
 import com.google.common.base.Stopwatch;
 import com.google.gson.JsonObject;
 import dev.architectury.loom.util.MappingOption;
+import org.apache.tools.ant.util.StringUtils;
 import org.gradle.api.Project;
 import org.gradle.api.artifacts.Configuration;
 import org.jetbrains.annotations.Nullable;
@@ -69,8 +68,8 @@ import net.fabricmc.loom.util.FileSystemUtil;
 import net.fabricmc.loom.util.ZipUtils;
 import net.fabricmc.loom.util.service.ScopedSharedServiceManager;
 import net.fabricmc.loom.util.service.SharedServiceManager;
-import net.fabricmc.loom.util.srg.MCPReader;
 import net.fabricmc.loom.util.srg.ForgeMappingsMerger;
+import net.fabricmc.loom.util.srg.MCPReader;
 import net.fabricmc.loom.util.srg.SrgNamedWriter;
 import net.fabricmc.mappingio.MappingReader;
 import net.fabricmc.mappingio.format.MappingFormat;
@@ -334,12 +333,7 @@ public class MappingConfiguration {
 			extractExtras(delegate.fs());
 		}
 
-		if (areMappingsMergedV2(baseTinyMappings)) {
-			// Architectury Loom Patch
-			// If a merged tiny v2 mappings file is provided
-			// Skip merging, should save a lot of time
-			Files.copy(baseTinyMappings, tinyMappings, StandardCopyOption.REPLACE_EXISTING);
-		} else if (areMappingsV2(baseTinyMappings)) {
+		if (areMappingsV2(baseTinyMappings)) {
 			// These are unmerged v2 mappings
 			IntermediateMappingsService intermediateMappingsService = IntermediateMappingsService.getInstance(serviceManager, project, minecraftProvider);
 
@@ -406,17 +400,6 @@ public class MappingConfiguration {
 		}
 	}
 
-	private static boolean areMappingsMergedV2(Path path) throws IOException {
-		try (BufferedReader reader = Files.newBufferedReader(path)) {
-			reader.mark(4096); // == DETECT_HEADER_LEN
-			boolean isTinyV2 = MappingReader.detectFormat(reader) == MappingFormat.TINY_2_FILE;
-			reader.reset();
-			return isTinyV2 && MappingReader.getNamespaces(reader, MappingFormat.TINY_2_FILE).containsAll(Arrays.asList("named", "intermediary", "official"));
-		} catch (NoSuchFileException e) {
-			return false;
-		}
-	}
-
 	public static void extractMappings(Path jar, Path extractTo) throws IOException {
 		try (FileSystemUtil.Delegate delegate = FileSystemUtil.getJarFileSystem(jar)) {
 			extractMappings(delegate.fs(), extractTo);