Move builtin transform selection to game provider (#1056)

Co-authored-by: Raik176 <[email protected]>
Co-authored-by: Space Walker <[email protected]>

Author: 3 people

minecraft/src/main/java/net/fabricmc/loader/impl/game/minecraft/MinecraftGameProvider.java

@@ -26,6 +26,7 @@
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
+import java.util.EnumSet;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
@@ -159,6 +160,29 @@ public boolean requiresUrlClassLoader() {
 		return hasModLoader;
 	}
 
+	@Override
+	public Set<BuiltinTransform> getBuiltinTransforms(String className) {
+		boolean isMinecraftClass = className.startsWith("net.minecraft.") // unobf classes in indev and later
+				|| className.startsWith("com.mojang.minecraft.") // unobf classes in classic
+				|| className.startsWith("com.mojang.rubydung.") // unobf classes in pre-classic
+				|| className.startsWith("com.mojang.blaze3d.") // unobf blaze3d classes
+				|| className.indexOf('.') < 0; // obf classes
+
+		if (isMinecraftClass) {
+			if (FabricLoaderImpl.INSTANCE.isDevelopmentEnvironment()) { // combined client+server jar, strip back down to production equivalent
+				return TRANSFORM_WIDENALL_STRIPENV_CLASSTWEAKS;
+			} else { // environment specific jar, inherently env stripped
+				return TRANSFORM_WIDENALL_CLASSTWEAKS;
+			}
+		} else { // mod class TODO: exclude game libs
+			return TRANSFORM_STRIPENV;
+		}
+	}
+
+	private static final Set<BuiltinTransform> TRANSFORM_WIDENALL_STRIPENV_CLASSTWEAKS = EnumSet.of(BuiltinTransform.WIDEN_ALL_PACKAGE_ACCESS, BuiltinTransform.STRIP_ENVIRONMENT, BuiltinTransform.CLASS_TWEAKS);
+	private static final Set<BuiltinTransform> TRANSFORM_WIDENALL_CLASSTWEAKS = EnumSet.of(BuiltinTransform.WIDEN_ALL_PACKAGE_ACCESS, BuiltinTransform.CLASS_TWEAKS);
+	private static final Set<BuiltinTransform> TRANSFORM_STRIPENV = EnumSet.of(BuiltinTransform.STRIP_ENVIRONMENT);
+
 	@Override
 	public boolean isEnabled() {
 		return !SystemProperties.isSet(SystemProperties.SKIP_MC_PROVIDER);

src/main/java/net/fabricmc/loader/impl/game/GameProvider.java

@@ -20,12 +20,15 @@
 import java.util.Collection;
 import java.util.List;
 import java.util.Objects;
+import java.util.Set;
 
+import net.fabricmc.api.Environment;
 import net.fabricmc.loader.api.metadata.ModMetadata;
 import net.fabricmc.loader.impl.game.patch.GameTransformer;
 import net.fabricmc.loader.impl.launch.FabricLauncher;
 import net.fabricmc.loader.impl.util.Arguments;
 import net.fabricmc.loader.impl.util.LoaderUtil;
+import net.fabricmc.loader.impl.util.SystemProperties;
 
 public interface GameProvider { // name directly referenced in net.fabricmc.loader.impl.launch.knot.Knot.findEmbedddedGameProvider() and service loader records
 	String getGameId();
@@ -38,6 +41,24 @@ public interface GameProvider { // name directly referenced in net.fabricmc.load
 	Path getLaunchDirectory();
 	boolean isObfuscated();
 	boolean requiresUrlClassLoader();
+	Set<BuiltinTransform> getBuiltinTransforms(String className);
+
+	enum BuiltinTransform {
+		/**
+		 * Removes classes, fields and methods annotated with a different {@literal @}{@link Environment} from the current runtime.
+		 */
+		STRIP_ENVIRONMENT,
+		/**
+		 * Widens all package-internal access modifiers to public (protected and package-private, but not private).
+		 *
+		 * <p>This only has an effect if the mappings or {@link SystemProperties#FIX_PACKAGE_ACCESS} require these access modifications.
+		 */
+		WIDEN_ALL_PACKAGE_ACCESS,
+		/**
+		 * Applies class tweakers, including access wideners, as supplied by mods.
+		 */
+		CLASS_TWEAKS,
+	}
 
 	boolean isEnabled();
 	boolean locateGame(FabricLauncher launcher, String[] args);

src/main/java/net/fabricmc/loader/impl/transformer/FabricTransformer.java

@@ -16,21 +16,24 @@
 
 package net.fabricmc.loader.impl.transformer;
 
+import java.util.Set;
+
 import org.objectweb.asm.ClassReader;
 import org.objectweb.asm.ClassVisitor;
 import org.objectweb.asm.ClassWriter;
 
 import net.fabricmc.accesswidener.AccessWidenerClassVisitor;
 import net.fabricmc.api.EnvType;
 import net.fabricmc.loader.impl.FabricLoaderImpl;
+import net.fabricmc.loader.impl.game.GameProvider.BuiltinTransform;
 import net.fabricmc.loader.impl.launch.FabricLauncherBase;
 
 public final class FabricTransformer {
 	public static byte[] transform(boolean isDevelopment, EnvType envType, String name, byte[] bytes) {
-		boolean isMinecraftClass = name.startsWith("net.minecraft.") || name.startsWith("com.mojang.blaze3d.") || name.indexOf('.') < 0;
-		boolean transformAccess = isMinecraftClass && FabricLauncherBase.getLauncher().getMappingConfiguration().requiresPackageAccessHack();
-		boolean environmentStrip = !isMinecraftClass || isDevelopment;
-		boolean applyAccessWidener = isMinecraftClass && FabricLoaderImpl.INSTANCE.getAccessWidener().getTargets().contains(name);
+		Set<BuiltinTransform> transforms = FabricLoaderImpl.INSTANCE.getGameProvider().getBuiltinTransforms(name);
+		boolean transformAccess = transforms.contains(BuiltinTransform.WIDEN_ALL_PACKAGE_ACCESS) && FabricLauncherBase.getLauncher().getMappingConfiguration().requiresPackageAccessHack();
+		boolean environmentStrip = transforms.contains(BuiltinTransform.STRIP_ENVIRONMENT);
+		boolean applyAccessWidener = transforms.contains(BuiltinTransform.CLASS_TWEAKS) && FabricLoaderImpl.INSTANCE.getAccessWidener().getTargets().contains(name);
 
 		if (!transformAccess && !environmentStrip && !applyAccessWidener) {
 			return bytes;