Support adding excluded dependencies into shadow configuration

api/shadow.api

@@ -156,17 +156,21 @@ public class com/github/jengelman/gradle/plugins/shadow/relocation/SimpleRelocat
 public abstract interface class com/github/jengelman/gradle/plugins/shadow/tasks/DependencyFilter : java/io/Serializable {
 	public abstract fun dependency (Ljava/lang/Object;)Lorg/gradle/api/specs/Spec;
 	public abstract fun exclude (Lorg/gradle/api/specs/Spec;)V
+	public abstract fun getAddExcludedIntoShadowConfiguration ()Lorg/gradle/api/provider/Property;
 	public abstract fun include (Lorg/gradle/api/specs/Spec;)V
 	public abstract fun project (Ljava/lang/Object;)Lorg/gradle/api/specs/Spec;
 	public abstract fun resolve (Ljava/util/Collection;)Lorg/gradle/api/file/FileCollection;
 	public abstract fun resolve (Lorg/gradle/api/artifacts/Configuration;)Lorg/gradle/api/file/FileCollection;
+	public abstract fun resolveExcluded (Ljava/util/Collection;)Lorg/gradle/api/file/FileCollection;
+	public abstract fun resolveExcluded (Lorg/gradle/api/artifacts/Configuration;)Lorg/gradle/api/file/FileCollection;
 }
 
 public abstract class com/github/jengelman/gradle/plugins/shadow/tasks/DependencyFilter$AbstractDependencyFilter : com/github/jengelman/gradle/plugins/shadow/tasks/DependencyFilter {
 	public fun <init> (Lorg/gradle/api/Project;Ljava/util/List;Ljava/util/List;)V
 	public synthetic fun <init> (Lorg/gradle/api/Project;Ljava/util/List;Ljava/util/List;ILkotlin/jvm/internal/DefaultConstructorMarker;)V
 	public fun dependency (Ljava/lang/Object;)Lorg/gradle/api/specs/Spec;
 	public fun exclude (Lorg/gradle/api/specs/Spec;)V
+	public fun getAddExcludedIntoShadowConfiguration ()Lorg/gradle/api/provider/Property;
 	protected final fun getExcludeSpecs ()Ljava/util/List;
 	protected final fun getIncludeSpecs ()Ljava/util/List;
 	public fun include (Lorg/gradle/api/specs/Spec;)V
@@ -175,6 +179,8 @@ public abstract class com/github/jengelman/gradle/plugins/shadow/tasks/Dependenc
 	public fun resolve (Ljava/util/Collection;)Lorg/gradle/api/file/FileCollection;
 	protected abstract fun resolve (Ljava/util/Set;Ljava/util/Set;Ljava/util/Set;)V
 	public fun resolve (Lorg/gradle/api/artifacts/Configuration;)Lorg/gradle/api/file/FileCollection;
+	public fun resolveExcluded (Ljava/util/Collection;)Lorg/gradle/api/file/FileCollection;
+	public fun resolveExcluded (Lorg/gradle/api/artifacts/Configuration;)Lorg/gradle/api/file/FileCollection;
 }
 
 public abstract class com/github/jengelman/gradle/plugins/shadow/tasks/FindResourceInClasspath : org/gradle/api/DefaultTask, org/gradle/api/tasks/util/PatternFilterable {

src/functionalTest/kotlin/com/github/jengelman/gradle/plugins/shadow/JavaPluginsTest.kt

@@ -602,6 +602,33 @@ class JavaPluginsTest : BasePluginTest() {
     assertThat(value).isEqualTo("junit-3.8.2.jar")
   }
 
+  @Issue("https://github.com/GradleUp/shadow/issues/265")
+  @Test
+  fun addExcludedDependencyIntoShadowConfiguration() {
+    projectScript.appendText(
+      """
+        dependencies {
+          shadow 'my:a:1.0'
+          implementation 'my:b:1.0'
+        }
+        $shadowJarTask {
+          dependencies {
+            addExcludedIntoShadowConfiguration = true
+            exclude(dependency('my:b:1.0'))
+          }
+        }
+      """
+        .trimIndent()
+    )
+
+    runWithSuccess(shadowJarPath)
+
+    assertThat(outputShadowedJar).useAll {
+      containsOnly(*manifestEntries)
+      getMainAttr(classPathAttributeKey).isEqualTo("b-1.0.jar a-1.0.jar")
+    }
+  }
+
   @Issue("https://github.com/GradleUp/shadow/issues/203")
   @ParameterizedTest
   @EnumSource(ZipEntryCompression::class)

src/main/kotlin/com/github/jengelman/gradle/plugins/shadow/ShadowJavaPlugin.kt

@@ -46,6 +46,16 @@ constructor(private val softwareComponentFactory: SoftwareComponentFactory) : Pl
         task.configurations.convention(provider { listOf(runtimeConfiguration) })
       }
     artifacts.add(configurations.shadow.name, taskProvider)
+
+    val excludedFiles = taskProvider.map { task ->
+      val filter = task.dependencyFilter.get()
+      if (filter.addExcludedIntoShadowConfiguration.get()) {
+        filter.resolveExcluded(task.configurations.get())
+      } else {
+        files()
+      }
+    }
+    dependencies.add(configurations.shadow.name, excludedFiles)
   }
 
   protected open fun Project.configureConfigurations() {

src/main/kotlin/com/github/jengelman/gradle/plugins/shadow/tasks/DependencyFilter.kt

@@ -1,5 +1,6 @@
 package com.github.jengelman.gradle.plugins.shadow.tasks
 
+import com.github.jengelman.gradle.plugins.shadow.internal.property
 import java.io.Serializable
 import org.gradle.api.Project
 import org.gradle.api.artifacts.Configuration
@@ -8,11 +9,22 @@ import org.gradle.api.artifacts.ProjectDependency
 import org.gradle.api.artifacts.ResolvedArtifact
 import org.gradle.api.artifacts.ResolvedDependency
 import org.gradle.api.file.FileCollection
+import org.gradle.api.provider.Property
 import org.gradle.api.provider.Provider
 import org.gradle.api.specs.Spec
+import org.gradle.api.tasks.Input
 
 // DependencyFilter is used as Gradle Input in ShadowJar, so it must be Serializable.
 public interface DependencyFilter : Serializable {
+  /**
+   * When `true`, excluded dependencies will be added to the `shadow` configuration. This is useful
+   * when you want to exclude a dependency from the shadowed JAR, but still want it to be available
+   * at the `Class-Path` manifest attribute.
+   *
+   * Default is `false`.
+   */
+  @get:Input public val addExcludedIntoShadowConfiguration: Property<Boolean>
+
   /** Resolve a [configuration] against the [include]/[exclude] rules in the filter. */
   public fun resolve(configuration: Configuration): FileCollection
 
@@ -22,6 +34,18 @@ public interface DependencyFilter : Serializable {
    */
   public fun resolve(configurations: Collection<Configuration>): FileCollection
 
+  /**
+   * Resolve the excluded files of a [configuration] against the [include]/[exclude] rules in the
+   * filter.
+   */
+  public fun resolveExcluded(configuration: Configuration): FileCollection
+
+  /**
+   * Resolve the excluded files of all [configurations] against the [include]/[exclude] rules in the
+   * filter and combine the results.
+   */
+  public fun resolveExcluded(configurations: Collection<Configuration>): FileCollection
+
   /** Exclude dependencies that match the provided [spec]. */
   public fun exclude(spec: Spec<ResolvedDependency>)
 
@@ -39,6 +63,9 @@ public interface DependencyFilter : Serializable {
     @Transient protected val includeSpecs: MutableList<Spec<ResolvedDependency>> = mutableListOf(),
     @Transient protected val excludeSpecs: MutableList<Spec<ResolvedDependency>> = mutableListOf(),
   ) : DependencyFilter {
+    @Transient
+    override val addExcludedIntoShadowConfiguration: Property<Boolean> =
+      project.objects.property(false)
 
     protected abstract fun resolve(
       dependencies: Set<ResolvedDependency>,
@@ -47,19 +74,7 @@ public interface DependencyFilter : Serializable {
     )
 
     override fun resolve(configuration: Configuration): FileCollection {
-      return configuration -
-        project.files(
-          project.provider {
-            val includes = mutableSetOf<ResolvedDependency>()
-            val excludes = mutableSetOf<ResolvedDependency>()
-            resolve(
-              dependencies = configuration.resolvedConfiguration.firstLevelModuleDependencies,
-              includedDependencies = includes,
-              excludedDependencies = excludes,
-            )
-            excludes.flatMap { it.moduleArtifacts.map(ResolvedArtifact::getFile) }
-          }
-        )
+      return configuration - resolveExcluded(configuration)
     }
 
     override fun resolve(configurations: Collection<Configuration>): FileCollection {
@@ -68,6 +83,27 @@ public interface DependencyFilter : Serializable {
         .reduceOrNull { acc, fileCollection -> acc + fileCollection } ?: project.files()
     }
 
+    override fun resolveExcluded(configuration: Configuration): FileCollection {
+      return project.files(
+        project.provider {
+          val includes = mutableSetOf<ResolvedDependency>()
+          val excludes = mutableSetOf<ResolvedDependency>()
+          resolve(
+            dependencies = configuration.resolvedConfiguration.firstLevelModuleDependencies,
+            includedDependencies = includes,
+            excludedDependencies = excludes,
+          )
+          excludes.flatMap { it.moduleArtifacts.map(ResolvedArtifact::getFile) }
+        }
+      )
+    }
+
+    override fun resolveExcluded(configurations: Collection<Configuration>): FileCollection {
+      return configurations
+        .map { resolveExcluded(it) }
+        .reduceOrNull { acc, fileCollection -> acc + fileCollection } ?: project.files()
+    }
+
     override fun exclude(spec: Spec<ResolvedDependency>) {
       excludeSpecs.add(spec)
     }