Make shadowJar task cacheable

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,5 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-5.1.1-bin.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-5.6.2-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

src/main/groovy/com/github/jengelman/gradle/plugins/shadow/internal/UnusedTracker.groovy

@@ -6,6 +6,7 @@ import org.gradle.api.artifacts.Dependency
 import org.gradle.api.artifacts.ProjectDependency
 import org.gradle.api.artifacts.SelfResolvingDependency
 import org.gradle.api.file.FileCollection
+import org.gradle.api.tasks.InputFiles
 import org.gradle.api.tasks.SourceSet
 import org.vafer.jdependency.Clazz
 import org.vafer.jdependency.Clazzpath
@@ -50,6 +51,11 @@ class UnusedTracker {
         return new UnusedTracker(classDirs, apiJars, toMinimize)
     }
 
+    @InputFiles
+    FileCollection getToMinimize() {
+        return toMinimize
+    }
+
     private static boolean isProjectDependencyFile(File file, Dependency dep) {
         def fileName = file.name
         def dependencyName = dep.name

src/main/groovy/com/github/jengelman/gradle/plugins/shadow/relocation/CacheableRelocator.groovy

@@ -0,0 +1,17 @@
+package com.github.jengelman.gradle.plugins.shadow.relocation
+
+import java.lang.annotation.ElementType
+import java.lang.annotation.Retention
+import java.lang.annotation.RetentionPolicy
+import java.lang.annotation.Target
+
+/**
+ * Marks that a given instance of {@link Relocator} is is compatible with the Gradle build cache.
+ * In other words, it has its appropriate inputs annotated so that Gradle can consider them when
+ * determining the cache key.
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.TYPE)
+@interface CacheableRelocator {
+
+}

src/main/groovy/com/github/jengelman/gradle/plugins/shadow/relocation/SimpleRelocator.groovy

@@ -20,6 +20,7 @@
 package com.github.jengelman.gradle.plugins.shadow.relocation
 
 import org.codehaus.plexus.util.SelectorUtils
+import org.gradle.api.tasks.Input
 
 import java.util.regex.Pattern
 
@@ -30,6 +31,7 @@ import java.util.regex.Pattern
  * @author Mauro Talevi
  * @author John Engelman
  */
+@CacheableRelocator
 class SimpleRelocator implements Relocator {
 
     private final String pattern
@@ -43,7 +45,7 @@ class SimpleRelocator implements Relocator {
     private final Set<String> includes
 
     private final Set<String> excludes
-
+    
     private final boolean rawString
 
     SimpleRelocator() {
@@ -188,4 +190,39 @@ class SimpleRelocator implements Relocator {
             return sourceContent.replaceAll("\\b" + pattern, shadedPattern)
         }
     }
+
+    @Input
+    String getPattern() {
+        return pattern
+    }
+
+    @Input
+    String getPathPattern() {
+        return pathPattern
+    }
+
+    @Input
+    String getShadedPattern() {
+        return shadedPattern
+    }
+
+    @Input
+    String getShadedPathPattern() {
+        return shadedPathPattern
+    }
+
+    @Input
+    Set<String> getIncludes() {
+        return includes
+    }
+
+    @Input
+    Set<String> getExcludes() {
+        return excludes
+    }
+
+    @Input
+    boolean getRawString() {
+        return rawString
+    }
 }

src/main/groovy/com/github/jengelman/gradle/plugins/shadow/tasks/ShadowJar.java

@@ -2,29 +2,27 @@
 
 import com.github.jengelman.gradle.plugins.shadow.ShadowStats;
 import com.github.jengelman.gradle.plugins.shadow.internal.*;
+import com.github.jengelman.gradle.plugins.shadow.relocation.CacheableRelocator;
 import com.github.jengelman.gradle.plugins.shadow.relocation.Relocator;
 import com.github.jengelman.gradle.plugins.shadow.relocation.SimpleRelocator;
-import com.github.jengelman.gradle.plugins.shadow.transformers.AppendingTransformer;
-import com.github.jengelman.gradle.plugins.shadow.transformers.GroovyExtensionModuleTransformer;
-import com.github.jengelman.gradle.plugins.shadow.transformers.ServiceFileTransformer;
-import com.github.jengelman.gradle.plugins.shadow.transformers.Transformer;
+import com.github.jengelman.gradle.plugins.shadow.transformers.*;
 import org.gradle.api.Action;
+import org.gradle.api.Task;
 import org.gradle.api.artifacts.Configuration;
 import org.gradle.api.file.FileCollection;
 import org.gradle.api.internal.DocumentationRegistry;
 import org.gradle.api.internal.file.FileResolver;
 import org.gradle.api.internal.file.copy.CopyAction;
-import org.gradle.api.tasks.InputFiles;
-import org.gradle.api.tasks.Internal;
-import org.gradle.api.tasks.Optional;
-import org.gradle.api.tasks.TaskAction;
+import org.gradle.api.specs.Spec;
+import org.gradle.api.tasks.*;
 import org.gradle.api.tasks.bundling.Jar;
 import org.gradle.api.tasks.util.PatternSet;
 
 import java.util.ArrayList;
 import java.util.List;
 import java.util.concurrent.Callable;
 
+@CacheableTask
 public class ShadowJar extends Jar implements ShadowSpec {
 
     private List<Transformer> transformers;
@@ -46,6 +44,29 @@ public ShadowJar() {
         transformers = new ArrayList<>();
         relocators = new ArrayList<>();
         configurations = new ArrayList<>();
+
+        this.getInputs().property("minimize", new Callable<Boolean>() {
+            @Override
+            public Boolean call() throws Exception {
+                return minimizeJar;
+            }
+        });
+        this.getOutputs().doNotCacheIf("Has one or more transforms or relocators that are not cacheable", new Spec<Task>() {
+            @Override
+            public boolean isSatisfiedBy(Task task) {
+                for (Transformer transformer : transformers) {
+                    if (!isCacheableTransform(transformer.getClass())) {
+                        return true;
+                    }
+                }
+                for (Relocator relocator : relocators) {
+                    if (!isCacheableRelocator(relocator.getClass())) {
+                        return true;
+                    }
+                }
+                return false;
+            }
+        });
     }
 
     public ShadowJar minimize() {
@@ -93,7 +114,7 @@ protected void copy() {
         getLogger().info(shadowStats.toString());
     }
 
-    @InputFiles
+    @Classpath
     public FileCollection getIncludedDependencies() {
         return getProject().files(new Callable<FileCollection>() {
 
@@ -146,24 +167,33 @@ public ShadowJar transform(Class<? extends Transformer> clazz) throws Instantiat
      */
     public <T extends Transformer> ShadowJar transform(Class<T> clazz, Action<T> c) throws InstantiationException, IllegalAccessException {
         T transformer = clazz.newInstance();
-        if (c != null) {
-            c.execute(transformer);
-        }
-        transformers.add(transformer);
+        addTransform(transformer, c);
         return this;
     }
 
+    private boolean isCacheableTransform(Class<? extends Transformer> clazz) {
+        return clazz.isAnnotationPresent(CacheableTransformer.class);
+    }
+
     /**
      * Add a preconfigured transformer instance.
      *
      * @param transformer the transformer instance to add
      * @return this
      */
     public ShadowJar transform(Transformer transformer) {
-        transformers.add(transformer);
+        addTransform(transformer, null);
         return this;
     }
 
+    private <T extends Transformer> void addTransform(T transformer, Action<T> c) {
+        if (c != null) {
+            c.execute(transformer);
+        }
+
+        transformers.add(transformer);
+    }
+
     /**
      * Syntactic sugar for merging service files in JARs.
      *
@@ -266,10 +296,7 @@ public ShadowJar relocate(String pattern, String destination) {
      */
     public ShadowJar relocate(String pattern, String destination, Action<SimpleRelocator> configure) {
         SimpleRelocator relocator = new SimpleRelocator(pattern, destination, new ArrayList<String>(), new ArrayList<String>());
-        if (configure != null) {
-            configure.execute(relocator);
-        }
-        relocators.add(relocator);
+        addRelocator(relocator, configure);
         return this;
     }
 
@@ -280,7 +307,7 @@ public ShadowJar relocate(String pattern, String destination, Action<SimpleReloc
      * @return this
      */
     public ShadowJar relocate(Relocator relocator) {
-        relocators.add(relocator);
+        addRelocator(relocator, null);
         return this;
     }
 
@@ -294,6 +321,14 @@ public ShadowJar relocate(Class<? extends Relocator> relocatorClass) throws Inst
         return relocate(relocatorClass, null);
     }
 
+    private <R extends Relocator> void addRelocator(R relocator, Action<R> configure) {
+        if (configure != null) {
+            configure.execute(relocator);
+        }
+
+        relocators.add(relocator);
+    }
+
     /**
      * Add a relocator of the provided class and configure.
      *
@@ -303,14 +338,15 @@ public ShadowJar relocate(Class<? extends Relocator> relocatorClass) throws Inst
      */
     public <R extends Relocator> ShadowJar relocate(Class<R> relocatorClass, Action<R> configure) throws InstantiationException, IllegalAccessException {
         R relocator = relocatorClass.newInstance();
-        if (configure != null) {
-            configure.execute(relocator);
-        }
-        relocators.add(relocator);
+        addRelocator(relocator, configure);
         return this;
     }
 
-    @Internal
+    private boolean isCacheableRelocator(Class<? extends Relocator> relocatorClass) {
+        return relocatorClass.isAnnotationPresent(CacheableRelocator.class);
+    }
+
+    @Nested
     public List<Transformer> getTransformers() {
         return this.transformers;
     }
@@ -319,7 +355,7 @@ public void setTransformers(List<Transformer> transformers) {
         this.transformers = transformers;
     }
 
-    @Internal
+    @Nested
     public List<Relocator> getRelocators() {
         return this.relocators;
     }
@@ -328,7 +364,7 @@ public void setRelocators(List<Relocator> relocators) {
         this.relocators = relocators;
     }
 
-    @InputFiles @Optional
+    @Classpath @Optional
     public List<Configuration> getConfigurations() {
         return this.configurations;
     }

src/main/groovy/com/github/jengelman/gradle/plugins/shadow/transformers/AppendingTransformer.groovy

@@ -23,6 +23,7 @@ import org.apache.tools.zip.ZipEntry
 import org.apache.tools.zip.ZipOutputStream
 import org.codehaus.plexus.util.IOUtil
 import org.gradle.api.file.FileTreeElement
+import org.gradle.api.tasks.Input
 
 /**
  * A resource processor that appends content for a resource, separated by a newline.
@@ -32,6 +33,7 @@ import org.gradle.api.file.FileTreeElement
  * Modifications
  * @author John Engelman
  */
+@CacheableTransformer
 class AppendingTransformer implements Transformer {
     String resource
 
@@ -65,4 +67,9 @@ class AppendingTransformer implements Transformer {
         IOUtil.copy(new ByteArrayInputStream(data.toByteArray()), os)
         data.reset()
     }
+
+    @Input
+    String getResource() {
+        return resource
+    }
 }

src/main/groovy/com/github/jengelman/gradle/plugins/shadow/transformers/CacheableTransformer.groovy

@@ -0,0 +1,17 @@
+package com.github.jengelman.gradle.plugins.shadow.transformers
+
+import java.lang.annotation.ElementType
+import java.lang.annotation.Retention
+import java.lang.annotation.RetentionPolicy
+import java.lang.annotation.Target
+
+/**
+ * Marks that a given instance of {@link Transformer} is is compatible with the Gradle build cache.
+ * In other words, it has its appropriate inputs annotated so that Gradle can consider them when
+ * determining the cache key.
+ */
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.TYPE)
+@interface CacheableTransformer {
+
+}

src/main/groovy/com/github/jengelman/gradle/plugins/shadow/transformers/GroovyExtensionModuleTransformer.groovy

@@ -32,6 +32,7 @@ import org.codehaus.plexus.util.IOUtil
  * entries will all be merged into a single META-INF/services/org.codehaus.groovy.runtime.ExtensionModule resource
  * packaged into the resultant JAR produced by the shadowing process.
  */
+@CacheableTransformer
 class GroovyExtensionModuleTransformer implements Transformer {
 
     private static final GROOVY_EXTENSION_MODULE_DESCRIPTOR_PATH =

src/main/groovy/com/github/jengelman/gradle/plugins/shadow/transformers/ServiceFileTransformer.groovy

@@ -25,6 +25,7 @@ import org.apache.tools.zip.ZipEntry
 import org.apache.tools.zip.ZipOutputStream
 import org.gradle.api.file.FileTreeElement
 import org.gradle.api.specs.Spec
+import org.gradle.api.tasks.Input
 import org.gradle.api.tasks.util.PatternFilterable
 import org.gradle.api.tasks.util.PatternSet
 import org.codehaus.plexus.util.IOUtil
@@ -42,6 +43,7 @@ import org.codehaus.plexus.util.IOUtil
  * @author Charlie Knudsen
  * @author John Engelman
  */
+@CacheableTransformer
 class ServiceFileTransformer implements Transformer, PatternFilterable {
 
     private static final String SERVICES_PATTERN = "META-INF/services/**"
@@ -193,6 +195,7 @@ class ServiceFileTransformer implements Transformer, PatternFilterable {
      * {@inheritDoc}
      */
     @Override
+    @Input
     Set<String> getIncludes() {
         return patternSet.includes
     }
@@ -210,6 +213,7 @@ class ServiceFileTransformer implements Transformer, PatternFilterable {
      * {@inheritDoc}
      */
     @Override
+    @Input
     Set<String> getExcludes() {
         return patternSet.excludes
     }
@@ -222,5 +226,4 @@ class ServiceFileTransformer implements Transformer, PatternFilterable {
         patternSet.excludes = excludes
         return this
     }
-
 }