Include declarative recipe preconditions in recipe descriptors (#6777)

* Include declarative recipe preconditions in recipe descriptors

* Javadoc screw off

* Fix test expectation

Author: sambsnyd

rewrite-core/build.gradle.kts

@@ -46,5 +46,5 @@ tasks.withType<Javadoc> {
     //   symbol:   method onConstructor_()
     //   location: @interface AllArgsConstructor
     // 1 error
-    exclude("**/RpcObjectData.java")
+    exclude("**/RpcObjectData.java", "**/RecipeDescriptor.java")
 }

rewrite-core/src/main/java/org/openrewrite/Recipe.java

@@ -203,8 +203,6 @@ public String getInstanceNameSuffix() {
      * A set of strings used for categorizing related recipes. For example
      * "testing", "junit", "spring". Any individual tag should consist of a
      * single word, all lowercase.
-     *
-     * @return The tags.
      */
     @Getter
     final Set<String> tags = emptySet();
@@ -225,11 +223,21 @@ public final RecipeDescriptor getDescriptor() {
 
     protected RecipeDescriptor createRecipeDescriptor() {
         List<OptionDescriptor> options = getOptionDescriptors();
-        ArrayList<RecipeDescriptor> recipeList1 = new ArrayList<>();
-        for (Recipe next : getRecipeList()) {
-            recipeList1.add(next.getDescriptor());
+        List<RecipeDescriptor> preconditionDescriptors = emptyList();
+        if (this instanceof RecipePreconditions) {
+            RecipePreconditions recipeWithPreconditions = (RecipePreconditions) this;
+            List<Recipe> preconditions = recipeWithPreconditions.getPreconditions();
+            preconditionDescriptors = new ArrayList<>(preconditions.size());
+            for (Recipe precondition : preconditions) {
+                preconditionDescriptors.add(precondition.getDescriptor());
+            }
+        }
+
+        List<Recipe> recipeList = getRecipeList();
+        List<RecipeDescriptor> recipeDescriptors = new ArrayList<>(recipeList.size());
+        for (Recipe next : recipeList) {
+            recipeDescriptors.add(next.getDescriptor());
         }
-        recipeList1.trimToSize();
 
         URI recipeSource;
         try {
@@ -239,7 +247,7 @@ protected RecipeDescriptor createRecipeDescriptor() {
         }
 
         return new RecipeDescriptor(getName(), getDisplayName(), getInstanceName(), getDescription(), getTags(),
-                getEstimatedEffortPerOccurrence(), options, recipeList1, getDataTableDescriptors(),
+                getEstimatedEffortPerOccurrence(), options, preconditionDescriptors, recipeDescriptors, getDataTableDescriptors(),
                 getMaintainers(), getContributors(), getExamples(), recipeSource);
     }
 

rewrite-core/src/main/java/org/openrewrite/config/DeclarativeRecipe.java

@@ -32,7 +32,7 @@
 import static org.openrewrite.Validated.invalid;
 
 @RequiredArgsConstructor
-public class DeclarativeRecipe extends ScanningRecipe<DeclarativeRecipe.Accumulator> {
+public class DeclarativeRecipe extends ScanningRecipe<DeclarativeRecipe.Accumulator> implements RecipePreconditions {
     @Getter
     private final String name;
 
@@ -187,7 +187,6 @@ private void registerNestedScanningRecipes(Recipe recipe, Accumulator acc, Execu
     @Override
     public TreeVisitor<?, ExecutionContext> getScanner(Accumulator acc) {
         return new TreeVisitor<Tree, ExecutionContext>() {
-            @SuppressWarnings({"rawtypes", "unchecked"})
             @Override
             public @Nullable Tree visit(@Nullable Tree tree, ExecutionContext ctx) {
                 for (Recipe precondition : preconditions) {
@@ -251,7 +250,7 @@ public boolean isAcceptable(SourceFile sourceFile, ExecutionContext ctx) {
 
     @EqualsAndHashCode(callSuper = false)
     @Value
-    static class BellwetherDecoratedRecipe extends Recipe implements DelegatingRecipe {
+    static class BellwetherDecoratedRecipe extends Recipe implements DelegatingRecipe, RecipePreconditions {
 
         DeclarativeRecipe.PreconditionBellwether bellwether;
         Recipe delegate;
@@ -350,11 +349,19 @@ public Validated<Object> validate(ExecutionContext ctx) {
         public Collection<Validated<Object>> validateAll(ExecutionContext ctx, Collection<Validated<Object>> acc) {
             return delegate.validateAll(ctx, acc);
         }
+
+        @Override
+        public List<Recipe> getPreconditions() {
+            if (delegate instanceof RecipePreconditions) {
+                return ((RecipePreconditions) delegate).getPreconditions();
+            }
+            return emptyList();
+        }
     }
 
     @Value
     @EqualsAndHashCode(callSuper = false)
-    static class BellwetherDecoratedScanningRecipe<T> extends ScanningRecipe<T> implements DelegatingRecipe {
+    static class BellwetherDecoratedScanningRecipe<T> extends ScanningRecipe<T> implements DelegatingRecipe, RecipePreconditions {
 
         DeclarativeRecipe.PreconditionBellwether bellwether;
         ScanningRecipe<T> delegate;
@@ -468,6 +475,14 @@ public Validated<Object> validate(ExecutionContext ctx) {
         public Collection<Validated<Object>> validateAll(ExecutionContext ctx, Collection<Validated<Object>> acc) {
             return delegate.validateAll(ctx, acc);
         }
+
+        @Override
+        public List<Recipe> getPreconditions() {
+            if (delegate instanceof RecipePreconditions) {
+                return ((RecipePreconditions) delegate).getPreconditions();
+            }
+            return emptyList();
+        }
     }
 
     @Override
@@ -589,13 +604,17 @@ private static class LazyLoadedRecipe extends Recipe {
 
     @Override
     protected RecipeDescriptor createRecipeDescriptor() {
-        List<RecipeDescriptor> recipeList = new ArrayList<>();
-        for (Recipe childRecipe : this.recipeList) {
-            recipeList.add(childRecipe.getDescriptor());
+        List<RecipeDescriptor> preconditionDescriptors = new ArrayList<>();
+        for (Recipe childRecipe : preconditions) {
+            preconditionDescriptors.add(childRecipe.getDescriptor());
+        }
+        List<RecipeDescriptor> recipeDescriptors = new ArrayList<>();
+        for (Recipe childRecipe : recipeList) {
+            recipeDescriptors.add(childRecipe.getDescriptor());
         }
         return new RecipeDescriptor(getName(), getDisplayName(), getInstanceName(), getDescription() != null ? getDescription() : "",
                 getTags(), getEstimatedEffortPerOccurrence(),
-                emptyList(), recipeList, getDataTableDescriptors(), getMaintainers(), getContributors(),
+                emptyList(), preconditionDescriptors, recipeDescriptors, getDataTableDescriptors(), getMaintainers(), getContributors(),
                 getExamples(), source);
     }
 

rewrite-core/src/main/java/org/openrewrite/config/RecipeDescriptor.java

@@ -15,6 +15,8 @@
  */
 package org.openrewrite.config;
 
+import com.fasterxml.jackson.annotation.JsonCreator;
+import lombok.AllArgsConstructor;
 import lombok.EqualsAndHashCode;
 import lombok.Value;
 import lombok.With;
@@ -36,6 +38,7 @@
 
 @Value
 @EqualsAndHashCode(onlyExplicitlyIncluded = true)
+@AllArgsConstructor(onConstructor = @__(@JsonCreator))
 public class RecipeDescriptor {
     @EqualsAndHashCode.Include
     String name;
@@ -57,6 +60,9 @@ public class RecipeDescriptor {
     @EqualsAndHashCode.Include
     List<OptionDescriptor> options;
 
+    @With
+    List<RecipeDescriptor> preconditions;
+
     @With
     List<RecipeDescriptor> recipeList;
 
@@ -73,6 +79,16 @@ public class RecipeDescriptor {
     @Deprecated
     URI source;
 
+    @Deprecated
+    public RecipeDescriptor(String name, String displayName, String instanceName, String description,
+                            Set<String> tags, @Nullable Duration estimatedEffortPerOccurrence,
+                            List<OptionDescriptor> options, List<RecipeDescriptor> recipeList,
+                            List<DataTableDescriptor> dataTables, List<Maintainer> maintainers,
+                            List<Contributor> contributors, List<RecipeExample> examples, URI source) {
+        this(name, displayName, instanceName, description, tags, estimatedEffortPerOccurrence,
+                options, emptyList(), recipeList, dataTables, maintainers, contributors, examples, source);
+    }
+
     /**
      * @param env Provides a source of category descriptors to build category names from more
      *            than just the name segments.

rewrite-core/src/main/java/org/openrewrite/config/RecipePreconditions.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2026 the original author or authors.
+ * <p>
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * <p>
+ * https://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.openrewrite.config;
+
+import org.openrewrite.Recipe;
+
+import java.util.List;
+
+/**
+ * Indicates that a recipe exposes a list of recipes used as preconditions.
+ * This is purely informational and not taken into consideration by recipe execution.
+ * Imperative recipes interact with preconditions as implementation details of their visitor(s).
+ * There is no reason for an imperative recipe to implement this, it will not affect the behavior of the recipe in any way.
+ */
+public interface RecipePreconditions {
+    List<Recipe> getPreconditions();
+}

rewrite-core/src/test/java/org/openrewrite/config/DeclarativeRecipeTest.java

@@ -39,6 +39,7 @@
 import static org.openrewrite.test.RewriteTest.toRecipe;
 import static org.openrewrite.test.SourceSpecs.text;
 
+@SuppressWarnings("NullableProblems")
 class DeclarativeRecipeTest implements RewriteTest {
 
     @DocumentExample
@@ -105,30 +106,22 @@ public PlainText visitText(PlainText text, ExecutionContext ctx) {
     }
 
     @Test
-    void descriptorDoesNotLeakBellwetherWhenPreconditionsPresent() {
+    void preconditionDescriptorsIncludedInDescriptor() {
         DeclarativeRecipe dr = new DeclarativeRecipe("test", "test", "test", emptySet(),
           null, URI.create("dummy"), true, emptyList());
-        dr.addPrecondition(
-          toRecipe(() -> new PlainTextVisitor<>() {
-              @Override
-              public PlainText visitText(PlainText text, ExecutionContext ctx) {
-                  if ("1".equals(text.getText())) {
-                      return SearchResult.found(text);
-                  }
-                  return text;
-              }
-          })
-        );
+        dr.addPrecondition(new Find("precondition-marker", null, null, null, null, null, null, null));
         dr.addUninitialized(new ChangeText("2"));
-        dr.addUninitialized(new ChangeText("3"));
         dr.initialize(List.of());
 
         RecipeDescriptor descriptor = dr.getDescriptor();
+        assertThat(descriptor.getPreconditions())
+          .hasSize(1)
+          .first()
+          .satisfies(p -> assertThat(p.getName()).isEqualTo("org.openrewrite.text.Find"));
         assertThat(descriptor.getRecipeList())
-          .hasSize(2)
-          .extracting(RecipeDescriptor::getName)
-          .noneMatch(name -> name.contains("Bellwether"))
-          .noneMatch(name -> name.contains("BellwetherDecorated"));
+          .hasSize(1)
+          .first()
+          .satisfies(r -> assertThat(r.getName()).isEqualTo("org.openrewrite.text.ChangeText"));
     }
 
     @Test
@@ -281,7 +274,6 @@ void yamlPreconditionWithScanningRecipe() {
               """, "org.openrewrite.PreconditionTest")
             .afterRecipe(run -> assertThat(run.getChangeset().getAllResults()).anySatisfy(
               s -> {
-                  //noinspection DataFlowIssue
                   assertThat(s.getAfter()).isNotNull();
                   assertThat(s.getAfter().getSourcePath()).isEqualTo(Path.of("test.txt"));
               }