create backup jars for legacy merged mapped minecraft providers (#1230)

* create backup jars for legacy merged mapped mc providers

* only merge jars if remapping occurred

* Cleanup + add logger

* Fixes

---------

Co-authored-by: modmuss50 <modmuss50@gmail.com>

src/main/java/net/fabricmc/loom/configuration/providers/minecraft/mapped/AbstractMappedMinecraftProvider.java

@@ -37,6 +37,8 @@ import java.util.StringJoiner;
 import java.util.function.Function;
 
 import org.gradle.api.Project;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 import net.fabricmc.loom.LoomGradleExtension;
 import net.fabricmc.loom.api.mappings.layered.MappingsNamespace;
@@ -56,6 +58,8 @@ import net.fabricmc.tinyremapper.OutputConsumerPath;
 import net.fabricmc.tinyremapper.TinyRemapper;
 
 public abstract class AbstractMappedMinecraftProvider<M extends MinecraftProvider> implements MappedMinecraftProvider.ProviderImpl {
+	private static final Logger LOGGER = LoggerFactory.getLogger(AbstractMappedMinecraftProvider.class);
+
 	protected final M minecraftProvider;
 	private final Project project;
 	protected final LoomGradleExtension extension;
@@ -68,8 +72,18 @@ public abstract class AbstractMappedMinecraftProvider<M extends MinecraftProvide
 
 	public abstract MappingsNamespace getTargetNamespace();
 
+	/**
+	 * @return A list of jars that should be remapped
+	 */
 	public abstract List<RemappedJars> getRemappedJars();
 
+	/**
+	 * @return A list of output jars that this provider generates
+	 */
+	public List<? extends OutputJar> getOutputJars() {
+		return getRemappedJars();
+	}
+
 	// Returns a list of MinecraftJar.Type's that this provider exports to be used as a dependency
 	public List<MinecraftJar.Type> getDependencyTypes() {
 		return Collections.emptyList();
@@ -85,7 +99,7 @@ public abstract class AbstractMappedMinecraftProvider<M extends MinecraftProvide
 			throw new IllegalStateException("No remapped jars provided");
 		}
 
-		if (!areOutputsValid(remappedJars) || context.refreshOutputs() || !hasBackupJars(minecraftJars)) {
+		if (shouldRefreshOutputs(context)) {
 			try {
 				remapInputs(remappedJars, context.configContext());
 				createBackupJars(minecraftJars);
@@ -116,16 +130,6 @@ public abstract class AbstractMappedMinecraftProvider<M extends MinecraftProvide
 		return outputJarPath.resolveSibling(outputJarPath.getFileName() + ".backup");
 	}
 
-	protected boolean hasBackupJars(List<MinecraftJar> minecraftJars) {
-		for (MinecraftJar minecraftJar : minecraftJars) {
-			if (!Files.exists(getBackupJarPath(minecraftJar))) {
-				return false;
-			}
-		}
-
-		return true;
-	}
-
 	protected void createBackupJars(List<MinecraftJar> minecraftJars) throws IOException {
 		for (MinecraftJar minecraftJar : minecraftJars) {
 			Files.copy(minecraftJar.getPath(), getBackupJarPath(minecraftJar), StandardCopyOption.REPLACE_EXISTING);
@@ -193,14 +197,34 @@ public abstract class AbstractMappedMinecraftProvider<M extends MinecraftProvide
 		return "net.minecraft:%s:%s".formatted(getName(type), getVersion());
 	}
 
-	private boolean areOutputsValid(List<RemappedJars> remappedJars) {
-		for (RemappedJars remappedJar : remappedJars) {
-			if (!getMavenHelper(remappedJar.type()).exists(null)) {
-				return false;
+	protected boolean shouldRefreshOutputs(ProvideContext context) {
+		if (context.refreshOutputs()) {
+			LOGGER.info("Refreshing outputs for mapped jar, as refresh outputs was requested");
+			return true;
+		}
+
+		final List<? extends OutputJar> outputJars = getOutputJars();
+
+		if (outputJars.isEmpty()) {
+			throw new IllegalStateException("No output jars provided");
+		}
+
+		for (OutputJar outputJar : outputJars) {
+			if (!getMavenHelper(outputJar.type()).exists(null)) {
+				LOGGER.info("Refreshing outputs for mapped jar, as {} does not exist", outputJar.outputJar());
+				return true;
 			}
 		}
 
-		return true;
+		for (OutputJar outputJar : outputJars) {
+			if (!Files.exists(getBackupJarPath(outputJar.outputJar()))) {
+				LOGGER.info("Refreshing outputs for mapped jar, as backup jar does not exist for {}", outputJar.outputJar());
+				return true;
+			}
+		}
+
+		LOGGER.debug("All outputs are up to date");
+		return false;
 	}
 
 	private void remapInputs(List<RemappedJars> remappedJars, ConfigContext configContext) throws IOException {
@@ -274,7 +298,15 @@ public abstract class AbstractMappedMinecraftProvider<M extends MinecraftProvide
 		return minecraftProvider;
 	}
 
-	public record RemappedJars(Path inputJar, MinecraftJar outputJar, MappingsNamespace sourceNamespace, Path... remapClasspath) {
+	public sealed interface OutputJar permits RemappedJars, SimpleOutputJar {
+		MinecraftJar outputJar();
+
+		default MinecraftJar.Type type() {
+			return outputJar().getType();
+		}
+	}
+
+	public record RemappedJars(Path inputJar, MinecraftJar outputJar, MappingsNamespace sourceNamespace, Path... remapClasspath) implements OutputJar {
 		public Path outputJarPath() {
 			return outputJar().getPath();
 		}
@@ -282,9 +314,8 @@ public abstract class AbstractMappedMinecraftProvider<M extends MinecraftProvide
 		public String name() {
 			return outputJar().getName();
 		}
+	}
 
-		public MinecraftJar.Type type() {
-			return outputJar().getType();
-		}
+	public record SimpleOutputJar(MinecraftJar outputJar) implements OutputJar {
 	}
 }

src/main/java/net/fabricmc/loom/configuration/providers/minecraft/mapped/IntermediaryMinecraftProvider.java

@@ -78,18 +78,30 @@ public abstract sealed class IntermediaryMinecraftProvider<M extends MinecraftPr
 
 		@Override
 		public List<MinecraftJar> provide(ProvideContext context) throws Exception {
+			final List<MinecraftJar> minecraftJars = List.of(getMergedJar());
+
+			// this check must be done before the client and server impls are provided
+			// because the merging only needs to happen if the remapping step is run
+			final boolean refreshOutputs = client.shouldRefreshOutputs(context)
+					|| server.shouldRefreshOutputs(context)
+					|| this.shouldRefreshOutputs(context);
+
 			// Map the client and server jars separately
 			server.provide(context);
 			client.provide(context);
 
-			// then merge them
-			MergedMinecraftProvider.mergeJars(
-						client.getEnvOnlyJar().toFile(),
-						server.getEnvOnlyJar().toFile(),
-						getMergedJar().toFile()
-			);
+			if (refreshOutputs) {
+				// then merge them
+				MergedMinecraftProvider.mergeJars(
+							client.getEnvOnlyJar().toFile(),
+							server.getEnvOnlyJar().toFile(),
+							getMergedJar().toFile()
+				);
 
-			return List.of(getMergedJar());
+				createBackupJars(minecraftJars);
+			}
+
+			return minecraftJars;
 		}
 
 		@Override
@@ -98,6 +110,13 @@ public abstract sealed class IntermediaryMinecraftProvider<M extends MinecraftPr
 			throw new UnsupportedOperationException("LegacyMergedImpl does not support getRemappedJars");
 		}
 
+		@Override
+		public List<? extends OutputJar> getOutputJars() {
+			return List.of(
+				new SimpleOutputJar(getMergedJar())
+			);
+		}
+
 		@Override
 		public List<MinecraftJar.Type> getDependencyTypes() {
 			return List.of(MinecraftJar.Type.MERGED);

src/main/java/net/fabricmc/loom/configuration/providers/minecraft/mapped/NamedMinecraftProvider.java

@@ -85,17 +85,28 @@ public abstract class NamedMinecraftProvider<M extends MinecraftProvider> extend
 		@Override
 		public List<MinecraftJar> provide(ProvideContext context) throws Exception {
 			final ProvideContext childContext = context.withApplyDependencies(false);
+			final List<MinecraftJar> minecraftJars = List.of(getMergedJar());
+
+			// this check must be done before the client and server impls are provided
+			// because the merging only needs to happen if the remapping step is run
+			final boolean refreshOutputs = client.shouldRefreshOutputs(childContext)
+					|| server.shouldRefreshOutputs(childContext)
+					|| this.shouldRefreshOutputs(childContext);
 
 			// Map the client and server jars separately
 			server.provide(childContext);
 			client.provide(childContext);
 
-			// then merge them
-			MergedMinecraftProvider.mergeJars(
-						client.getEnvOnlyJar().toFile(),
-						server.getEnvOnlyJar().toFile(),
-						getMergedJar().toFile()
-			);
+			if (refreshOutputs) {
+				// then merge them
+				MergedMinecraftProvider.mergeJars(
+							client.getEnvOnlyJar().toFile(),
+							server.getEnvOnlyJar().toFile(),
+							getMergedJar().toFile()
+				);
+
+				createBackupJars(minecraftJars);
+			}
 
 			getMavenHelper(MinecraftJar.Type.MERGED).savePom();
 
@@ -106,7 +117,7 @@ public abstract class NamedMinecraftProvider<M extends MinecraftProvider> extend
 				);
 			}
 
-			return List.of(getMergedJar());
+			return minecraftJars;
 		}
 
 		@Override
@@ -115,6 +126,13 @@ public abstract class NamedMinecraftProvider<M extends MinecraftProvider> extend
 			throw new UnsupportedOperationException("LegacyMergedImpl does not support getRemappedJars");
 		}
 
+		@Override
+		public List<? extends OutputJar> getOutputJars() {
+			return List.of(
+				new SimpleOutputJar(getMergedJar())
+			);
+		}
+
 		@Override
 		public List<MinecraftJar.Type> getDependencyTypes() {
 			return List.of(MinecraftJar.Type.MERGED);

src/main/java/net/fabricmc/loom/configuration/providers/minecraft/mapped/ProcessedNamedMinecraftProvider.java

@@ -65,7 +65,7 @@ public abstract class ProcessedNamedMinecraftProvider<M extends MinecraftProvide
 
 		parentMinecraftProvider.provide(context.withApplyDependencies(false));
 
-		boolean requiresProcessing = context.refreshOutputs() || !hasBackupJars(minecraftJars) || parentMinecraftJars.stream()
+		boolean requiresProcessing = shouldRefreshOutputs(context) || parentMinecraftJars.stream()
 				.map(this::getProcessedPath)
 				.anyMatch(jarProcessorManager::requiresProcessingJar);
 
@@ -81,6 +81,14 @@ public abstract class ProcessedNamedMinecraftProvider<M extends MinecraftProvide
 		return List.copyOf(minecraftJarOutputMap.values());
 	}
 
+	@Override
+	public List<? extends OutputJar> getOutputJars() {
+		return parentMinecraftProvider.getMinecraftJars().stream()
+				.map(this::getProcessedJar)
+				.map(SimpleOutputJar::new)
+				.toList();
+	}
+
 	@Override
 	public MavenScope getMavenScope() {
 		return MavenScope.LOCAL;