Fix incorrect remap configuration names for none main source sets.

src/main/java/net/fabricmc/loom/configuration/RemapConfigurations.java

@@ -34,6 +34,7 @@ import org.gradle.api.Project;
 import org.gradle.api.artifacts.Configuration;
 import org.gradle.api.plugins.JavaPlugin;
 import org.gradle.api.tasks.SourceSet;
+import org.jetbrains.annotations.VisibleForTesting;
 
 import net.fabricmc.loom.LoomGradleExtension;
 import net.fabricmc.loom.api.RemapConfigurationSettings;
@@ -161,7 +162,8 @@ public final class RemapConfigurations {
 		return str.substring(0, 1).toUpperCase(Locale.ROOT) + str.substring(1);
 	}
 
-	private record ConfigurationOption(Function<SourceSet, String> targetNameFunc, boolean compileClasspath, boolean runtimeClasspath, RemapConfigurationSettings.PublishingMode publishingMode) {
+	@VisibleForTesting
+	public record ConfigurationOption(Function<SourceSet, String> targetNameFunc, boolean compileClasspath, boolean runtimeClasspath, RemapConfigurationSettings.PublishingMode publishingMode) {
 		String targetName(SourceSet sourceSet) {
 			return targetNameFunc.apply(sourceSet);
 		}
@@ -170,27 +172,25 @@ public final class RemapConfigurations {
 			return targetName(sourceSet) != null;
 		}
 
-		String name(SourceSet sourceSet) {
+		public String name(SourceSet sourceSet) {
 			String targetName = targetName(sourceSet);
 
 			if (targetName == null) {
 				throw new UnsupportedOperationException("Configuration option is not available for sourceset (%s)".formatted(sourceSet.getName()));
 			}
 
-			final StringBuilder builder = new StringBuilder();
-
-			if (!SourceSet.MAIN_SOURCE_SET_NAME.equals(sourceSet.getName())) {
-				builder.append(sourceSet.getName());
+			if (targetName.startsWith(sourceSet.getName())) {
+				targetName = targetName.substring(sourceSet.getName().length());
 			}
 
-			if (builder.isEmpty()) {
-				builder.append("mod");
-			} else {
-				builder.append("Mod");
+			final StringBuilder builder = new StringBuilder();
+			builder.append("mod");
+
+			if (!SourceSet.MAIN_SOURCE_SET_NAME.equals(sourceSet.getName())) {
+				builder.append(capitalise(sourceSet.getName()));
 			}
 
 			builder.append(capitalise(targetName));
-
 			return builder.toString();
 		}
 	}

src/test/groovy/net/fabricmc/loom/test/unit/RemapConfigurationsTest.groovy

@@ -0,0 +1,53 @@
+/*
+ * This file is part of fabric-loom, licensed under the MIT License (MIT).
+ *
+ * Copyright (c) 2022 FabricMC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package net.fabricmc.loom.test.unit
+
+import net.fabricmc.loom.api.RemapConfigurationSettings
+import net.fabricmc.loom.configuration.RemapConfigurations
+import net.fabricmc.loom.test.util.GradleTestUtil
+import org.gradle.api.tasks.SourceSet
+import spock.lang.Specification
+
+class RemapConfigurationsTest extends Specification {
+	private static final RemapConfigurations.ConfigurationOption IMPLEMENTATION_OPTION = new RemapConfigurations.ConfigurationOption(SourceSet::getImplementationConfigurationName, true, true, RemapConfigurationSettings.PublishingMode.RUNTIME_ONLY)
+
+	def "testmod impl name"() {
+		given:
+			def sourceSet = GradleTestUtil.mockSourceSet("testmod")
+		when:
+			def name = IMPLEMENTATION_OPTION.name(sourceSet)
+		then:
+			name == "modTestmodImplementation"
+	}
+
+	def "main impl name"() {
+		given:
+			def sourceSet = GradleTestUtil.mockSourceSet("main")
+		when:
+			def name = IMPLEMENTATION_OPTION.name(sourceSet)
+		then:
+			name == "modImplementation"
+	}
+}

src/test/groovy/net/fabricmc/loom/test/util/GradleTestUtil.groovy

@@ -24,8 +24,15 @@
 
 package net.fabricmc.loom.test.util
 
+import org.gradle.api.file.SourceDirectorySet
+import org.gradle.api.internal.tasks.DefaultSourceSet
+import org.gradle.api.model.ObjectFactory
+import org.gradle.api.plugins.ExtensionContainer
 import org.gradle.api.provider.Property
+import org.gradle.api.tasks.SourceSet
+import org.gradle.api.tasks.util.PatternFilterable
 
+import static org.mockito.ArgumentMatchers.any
 import static org.mockito.Mockito.mock
 import static org.mockito.Mockito.when
 
@@ -35,4 +42,30 @@ class GradleTestUtil {
         when(mock.get()).thenReturn(Objects.requireNonNull(value))
         return mock
     }
+
+	static SourceSet mockSourceSet(String name) {
+		def sourceSet = new DefaultSourceSet(name, mockObjectFactory()) {
+			final ExtensionContainer extensions = null
+		}
+		return sourceSet
+	}
+
+	static ObjectFactory mockObjectFactory() {
+		def mock = mock(ObjectFactory.class)
+		def mockSourceDirectorySet = mockSourceDirectorySet()
+		when(mock.sourceDirectorySet(any(), any())).thenReturn(mockSourceDirectorySet)
+		return mock
+	}
+
+	static SourceDirectorySet mockSourceDirectorySet() {
+		def mock = mock(SourceDirectorySet.class)
+		def mockPatternFilterable = mockPatternFilterable()
+		when(mock.getFilter()).thenReturn(mockPatternFilterable)
+		return mock
+	}
+
+	static PatternFilterable mockPatternFilterable() {
+		def mock = mock(PatternFilterable.class)
+		return mock
+	}
 }