Add Data marker interface for transition factories.

Part of the fix for #13751.

Closes #13754.

PiperOrigin-RevId: 387161899

src/main/java/com/google/devtools/build/lib/analysis/config/HostTransition.java

@@ -62,21 +62,22 @@ public BuildOptions patch(BuildOptionsView options, EventHandler eventHandler) {
   }
 
   /** Returns a {@link TransitionFactory} instance that generates the host transition. */
-  public static <T> TransitionFactory<T> createFactory() {
+  public static <T extends TransitionFactory.Data> TransitionFactory<T> createFactory() {
     return new AutoValue_HostTransition_Factory<>();
   }
 
   /**
    * Returns {@code true} if the given {@link TransitionFactory} is an instance of the host
    * transition.
    */
-  public static <T> boolean isInstance(TransitionFactory<T> instance) {
+  public static <T extends TransitionFactory.Data> boolean isInstance(
+      TransitionFactory<T> instance) {
     return instance instanceof Factory;
   }
 
   /** A {@link TransitionFactory} implementation that generates the host transition. */
   @AutoValue
-  abstract static class Factory<T> implements TransitionFactory<T> {
+  abstract static class Factory<T extends TransitionFactory.Data> implements TransitionFactory<T> {
     @Override
     public PatchTransition create(T unused) {
       return INSTANCE;

src/main/java/com/google/devtools/build/lib/analysis/config/TransitionFactories.java

@@ -28,7 +28,8 @@ public final class TransitionFactories {
   private TransitionFactories() {}
 
   /** Returns a {@link TransitionFactory} that wraps a static transition. */
-  public static <T> TransitionFactory<T> of(ConfigurationTransition transition) {
+  public static <T extends TransitionFactory.Data> TransitionFactory<T> of(
+      ConfigurationTransition transition) {
     if (transition instanceof HostTransition) {
       return HostTransition.createFactory();
     } else if (transition instanceof NoTransition) {
@@ -42,13 +43,15 @@ public static <T> TransitionFactory<T> of(ConfigurationTransition transition) {
   }
 
   /** Returns a {@link TransitionFactory} that wraps a static split transition. */
-  public static <T> TransitionFactory<T> split(SplitTransition splitTransition) {
+  public static <T extends TransitionFactory.Data> TransitionFactory<T> split(
+      SplitTransition splitTransition) {
     return new AutoValue_TransitionFactories_SplitTransitionFactory<T>(splitTransition);
   }
 
   /** A {@link TransitionFactory} implementation that wraps a static transition. */
   @AutoValue
-  abstract static class IdentityFactory<T> implements TransitionFactory<T> {
+  abstract static class IdentityFactory<T extends TransitionFactory.Data>
+      implements TransitionFactory<T> {
 
     abstract ConfigurationTransition transition();
 
@@ -60,7 +63,8 @@ public ConfigurationTransition create(T data) {
 
   /** A {@link TransitionFactory} implementation that wraps a split transition. */
   @AutoValue
-  abstract static class SplitTransitionFactory<T> implements TransitionFactory<T> {
+  abstract static class SplitTransitionFactory<T extends TransitionFactory.Data>
+      implements TransitionFactory<T> {
     abstract SplitTransition splitTransition();
 
     @Override

src/main/java/com/google/devtools/build/lib/analysis/config/transitions/ComposingTransitionFactory.java

@@ -29,7 +29,8 @@
  * </pre>
  */
 @AutoValue
-public abstract class ComposingTransitionFactory<T> implements TransitionFactory<T> {
+public abstract class ComposingTransitionFactory<T extends TransitionFactory.Data>
+    implements TransitionFactory<T> {
 
   /**
    * Creates a {@link ComposingTransitionFactory} that applies the given factories in sequence:
@@ -39,7 +40,7 @@ public abstract class ComposingTransitionFactory<T> implements TransitionFactory
    * one of the transitions is {@link NoTransition} or the host transition, and returns an
    * efficiently composed transition.
    */
-  public static <T> TransitionFactory<T> of(
+  public static <T extends TransitionFactory.Data> TransitionFactory<T> of(
       TransitionFactory<T> transitionFactory1, TransitionFactory<T> transitionFactory2) {
 
     Preconditions.checkNotNull(transitionFactory1);
@@ -71,11 +72,12 @@ public static <T> TransitionFactory<T> of(
     return create(transitionFactory1, transitionFactory2);
   }
 
-  private static <T> boolean isFinal(TransitionFactory<T> transitionFactory) {
+  private static <T extends TransitionFactory.Data> boolean isFinal(
+      TransitionFactory<T> transitionFactory) {
     return NullTransition.isInstance(transitionFactory) || transitionFactory.isHost();
   }
 
-  private static <T> TransitionFactory<T> create(
+  private static <T extends TransitionFactory.Data> TransitionFactory<T> create(
       TransitionFactory<T> transitionFactory1, TransitionFactory<T> transitionFactory2) {
     return new AutoValue_ComposingTransitionFactory<T>(transitionFactory1, transitionFactory2);
   }

src/main/java/com/google/devtools/build/lib/analysis/config/transitions/NoTransition.java

@@ -32,21 +32,22 @@ public BuildOptions patch(BuildOptionsView options, EventHandler eventHandler) {
   }
 
   /** Returns a {@link TransitionFactory} instance that generates the no transition. */
-  public static <T> TransitionFactory<T> createFactory() {
+  public static <T extends TransitionFactory.Data> TransitionFactory<T> createFactory() {
     return new AutoValue_NoTransition_Factory<>();
   }
 
   /**
    * Returns {@code true} if the given {@link TransitionFactory} is an instance of the no
    * transition.
    */
-  public static <T> boolean isInstance(TransitionFactory<T> instance) {
+  public static <T extends TransitionFactory.Data> boolean isInstance(
+      TransitionFactory<T> instance) {
     return instance instanceof Factory;
   }
 
   /** A {@link TransitionFactory} implementation that generates the no transition. */
   @AutoValue
-  abstract static class Factory<T> implements TransitionFactory<T> {
+  abstract static class Factory<T extends TransitionFactory.Data> implements TransitionFactory<T> {
     @Override
     public ConfigurationTransition create(T unused) {
       return INSTANCE;

src/main/java/com/google/devtools/build/lib/analysis/config/transitions/NullTransition.java

@@ -37,21 +37,22 @@ public BuildOptions patch(BuildOptionsView options, EventHandler eventHandler) {
   }
 
   /** Returns a {@link TransitionFactory} instance that generates the null transition. */
-  public static <T> TransitionFactory<T> createFactory() {
+  public static <T extends TransitionFactory.Data> TransitionFactory<T> createFactory() {
     return new AutoValue_NullTransition_Factory<>();
   }
 
   /**
    * Returns {@code true} if the given {@link TransitionFactory} is an instance of the null
    * transition.
    */
-  public static <T> boolean isInstance(TransitionFactory<T> instance) {
+  public static <T extends TransitionFactory.Data> boolean isInstance(
+      TransitionFactory<T> instance) {
     return instance instanceof Factory;
   }
 
   /** A {@link TransitionFactory} implementation that generates the null transition. */
   @AutoValue
-  abstract static class Factory<T> implements TransitionFactory<T> {
+  abstract static class Factory<T extends TransitionFactory.Data> implements TransitionFactory<T> {
     @Override
     public ConfigurationTransition create(T unused) {
       return INSTANCE;

src/main/java/com/google/devtools/build/lib/analysis/config/transitions/TransitionFactory.java

@@ -29,7 +29,10 @@
  * @param <T> the type of data object passed to the {@link #create} method, used to create the
  *     actual {@link ConfigurationTransition} instance
  */
-public interface TransitionFactory<T> {
+public interface TransitionFactory<T extends TransitionFactory.Data> {
+
+  /** A marker interface for classes that provide data to TransitionFactory instances. */
+  interface Data {}
 
   /** Returns a new {@link ConfigurationTransition}, based on the given data. */
   ConfigurationTransition create(T data);

src/main/java/com/google/devtools/build/lib/bazel/rules/objc/BazelAppleBinaryRule.java

@@ -17,8 +17,10 @@
 import com.google.devtools.build.lib.analysis.RuleDefinition;
 import com.google.devtools.build.lib.analysis.RuleDefinitionEnvironment;
 import com.google.devtools.build.lib.analysis.config.transitions.ComposingTransitionFactory;
+import com.google.devtools.build.lib.analysis.config.transitions.TransitionFactory;
 import com.google.devtools.build.lib.packages.ImplicitOutputsFunction;
 import com.google.devtools.build.lib.packages.RuleClass;
+import com.google.devtools.build.lib.packages.RuleTransitionData;
 import com.google.devtools.build.lib.rules.config.ConfigFeatureFlagTransitionFactory;
 import com.google.devtools.build.lib.rules.objc.AppleBinaryBaseRule;
 import com.google.devtools.build.lib.rules.objc.AppleCrosstoolTransition;
@@ -39,7 +41,8 @@ public RuleClass build(RuleClass.Builder builder, RuleDefinitionEnvironment env)
             ImplicitOutputsFunction.fromFunctions(ObjcRuleClasses.LIPOBIN_OUTPUT))
         .cfg(
             ComposingTransitionFactory.of(
-                (rule) -> AppleCrosstoolTransition.APPLE_CROSSTOOL_TRANSITION,
+                (TransitionFactory<RuleTransitionData>)
+                    (unused) -> AppleCrosstoolTransition.APPLE_CROSSTOOL_TRANSITION,
                 new ConfigFeatureFlagTransitionFactory("feature_flags")))
         .build();
   }

src/main/java/com/google/devtools/build/lib/packages/AttributeTransitionData.java

@@ -14,16 +14,16 @@
 package com.google.devtools.build.lib.packages;
 
 import com.google.auto.value.AutoValue;
+import com.google.devtools.build.lib.analysis.config.transitions.TransitionFactory;
 import com.google.devtools.build.lib.cmdline.Label;
 import javax.annotation.Nullable;
 
 /**
- * Helper class which contains data used by a {@link
- * com.google.devtools.build.lib.analysis.config.transitions.TransitionFactory} to create a
- * transition for attributes.
+ * Helper class which contains data used by a {@link TransitionFactory} to create a transition for
+ * attributes.
  */
 @AutoValue
-public abstract class AttributeTransitionData {
+public abstract class AttributeTransitionData implements TransitionFactory.Data {
   /** Returns the {@link AttributeMap} which can be used to create a transition. */
   public abstract AttributeMap attributes();
 

src/main/java/com/google/devtools/build/lib/packages/RuleTransitionData.java

@@ -14,14 +14,14 @@
 package com.google.devtools.build.lib.packages;
 
 import com.google.auto.value.AutoValue;
+import com.google.devtools.build.lib.analysis.config.transitions.TransitionFactory;
 
 /**
- * Helper class which contains data used by a {@link
- * com.google.devtools.build.lib.analysis.config.transitions.TransitionFactory} to create a
- * transition for rules.
+ * Helper class which contains data used by a {@link TransitionFactory} to create a transition for
+ * rules.
  */
 @AutoValue
-public abstract class RuleTransitionData {
+public abstract class RuleTransitionData implements TransitionFactory.Data {
 
   public static RuleTransitionData create(Rule rule) {
     return new AutoValue_RuleTransitionData(rule);

src/test/java/com/google/devtools/build/lib/analysis/config/TransitionFactoriesTest.java

@@ -30,7 +30,8 @@ public class TransitionFactoriesTest {
 
   @Test
   public void hostTransition() {
-    TransitionFactory<Object> factory = TransitionFactories.of(HostTransition.INSTANCE);
+    TransitionFactory<TransitionFactory.Data> factory =
+        TransitionFactories.of(HostTransition.INSTANCE);
     assertThat(factory).isNotNull();
     assertThat(HostTransition.isInstance(factory)).isTrue();
     assertThat(factory.isHost()).isTrue();
@@ -39,7 +40,8 @@ public void hostTransition() {
 
   @Test
   public void noTransition() {
-    TransitionFactory<Object> factory = TransitionFactories.of(NoTransition.INSTANCE);
+    TransitionFactory<TransitionFactory.Data> factory =
+        TransitionFactories.of(NoTransition.INSTANCE);
     assertThat(factory).isNotNull();
     assertThat(NoTransition.isInstance(factory)).isTrue();
     assertThat(factory.isHost()).isFalse();
@@ -48,7 +50,8 @@ public void noTransition() {
 
   @Test
   public void nullTransition() {
-    TransitionFactory<Object> factory = TransitionFactories.of(NullTransition.INSTANCE);
+    TransitionFactory<TransitionFactory.Data> factory =
+        TransitionFactories.of(NullTransition.INSTANCE);
     assertThat(factory).isNotNull();
     assertThat(NullTransition.isInstance(factory)).isTrue();
     assertThat(factory.isHost()).isFalse();
@@ -57,7 +60,7 @@ public void nullTransition() {
 
   @Test
   public void splitTransition() {
-    TransitionFactory<Object> factory =
+    TransitionFactory<TransitionFactory.Data> factory =
         TransitionFactories.of(
             (SplitTransition)
                 (buildOptions, eventHandler) ->

src/test/java/com/google/devtools/build/lib/analysis/config/transitions/ComposingTransitionFactoryTest.java

@@ -202,7 +202,7 @@ public void compose_nullTrans_second() {
     assertThat(NullTransition.isInstance(composed)).isTrue();
   }
 
-  private static final class StubData {}
+  private static final class StubData implements TransitionFactory.Data {}
 
   // Helper methods and classes for the tests.
   private static BuildOptions updateOptions(BuildOptions source, Label flag, String value) {