Allow direct Kotlin recipe instantiation in tests (#6578)

Author: timtebeek

…otlin/KotlinFromDeclarativeRecipeTest.kt …g/openrewrite/kotlin/KotlinRecipeTest.ktrewrite-kotlin/src/test/java/org/openrewrite/kotlin/KotlinFromDeclarativeRecipeTest.kt renamed to rewrite-kotlin/src/test/java/org/openrewrite/kotlin/KotlinRecipeTest.kt rewrite-kotlin/src/test/java/org/openrewrite/kotlin/KotlinFromDeclarativeRecipeTest.kt renamed to rewrite-kotlin/src/test/java/org/openrewrite/kotlin/KotlinRecipeTest.kt

@@ -22,35 +22,49 @@ import org.openrewrite.ExecutionContext
 import org.openrewrite.Option
 import org.openrewrite.Recipe
 import org.openrewrite.TreeVisitor
-import org.openrewrite.test.RecipeSpec
 import org.openrewrite.test.RewriteTest
 import org.openrewrite.test.SourceSpecs.text
 import org.openrewrite.text.PlainText
 import org.openrewrite.text.PlainTextVisitor
 
+class KotlinRecipeTest : RewriteTest {
 
-class KotlinFromDeclarativeRecipeTest : RewriteTest {
-    override fun defaults(spec: RecipeSpec) {
-        spec.recipeFromYaml(
-            """
-            type: specs.openrewrite.org/v1beta/recipe
-            name: org.openrewrite.kotlin.KotlinReplaceAllRecipeWrapper
-            displayName: Kotlin Replace All Wrapper
-            description: Tests a simple Kotlin recipe that replaces all text with the provided option.
-            recipeList:
-              - org.openrewrite.kotlin.KotlinReplaceAllRecipeJackson:
-                  replacementText: "REPLACED_WITH_JACKSON"
-              - org.openrewrite.kotlin.KotlinReplaceAllRecipe:
-                  replacementText: "REPLACED_WITH_KOTLIN"
-            """, "org.openrewrite.kotlin.KotlinReplaceAllRecipeWrapper"
+    @Test
+    fun `replaces all text with provided replacement argument text`() =
+        rewriteRun(
+            { spec ->
+                spec.cycles(1)
+                    .expectedCyclesThatMakeChanges(1)
+                    .recipeFromYaml(
+                    """
+                    type: specs.openrewrite.org/v1beta/recipe
+                    name: org.openrewrite.kotlin.KotlinReplaceAllRecipeWrapper
+                    displayName: Kotlin Replace All Wrapper
+                    description: Tests a simple Kotlin recipe that replaces all text with the provided option.
+                    recipeList:
+                      - org.openrewrite.kotlin.KotlinReplaceAllRecipeJackson:
+                          replacementText: "REPLACED_WITH_JACKSON"
+                      - org.openrewrite.kotlin.KotlinReplaceAllRecipe:
+                          replacementText: "REPLACED_WITH_KOTLIN"
+                    """,
+                    "org.openrewrite.kotlin.KotlinReplaceAllRecipeWrapper"
+                )
+            },
+            text("Some Text", "REPLACED_WITH_KOTLIN")
         )
-            .cycles(1)
-            .expectedCyclesThatMakeChanges(1)
-    }
 
+    /**
+     * This test directly uses a Kotlin recipe with required options (without the declarative wrapper).
+     * Before the fix in RewriteTest.java, this test would fail because Jackson's Kotlin module
+     * enforces non-nullability when trying to instantiate with null arguments via RecipeLoader.
+     * Now the RecipeLoader null-instantiation validation is skipped for Kotlin recipes with required options.
+     */
     @Test
-    fun `replaces all text with provided replacement argument text`() =
-        rewriteRun(text("Some Text", "REPLACED_WITH_KOTLIN"))
+    fun `directly uses kotlin recipe with required options`() =
+        rewriteRun(
+            { spec -> spec.recipe(KotlinReplaceAllRecipe("DIRECT_REPLACEMENT")) },
+            text("Some Text", "DIRECT_REPLACEMENT")
+        )
 }
 
 @Suppress("unused")

rewrite-test/src/main/java/org/openrewrite/test/RewriteTest.java

@@ -29,6 +29,8 @@
 import org.openrewrite.tree.ParseError;
 import org.openrewrite.tree.ParsingExecutionContextView;
 
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Field;
 import java.nio.charset.StandardCharsets;
 import java.nio.file.Path;
 import java.util.*;
@@ -174,19 +176,25 @@ default void rewriteRun(Consumer<RecipeSpec> spec, SourceSpec<?>... sourceSpecs)
             assertThat(recipeSerializer.read(recipeSerializer.write(recipe)))
                     .as("Recipe must be serializable/deserializable")
                     .isEqualTo(recipe);
-            assertThatCode(() -> {
-                Recipe r = new RecipeLoader(recipe.getClass().getClassLoader())
-                        .load(recipe.getClass(), null);
-                // getRecipeList should not fail with default parameters from RecipeLoader.
-                r.getRecipeList();
-                // We add recipes to HashSet in some places, we need to validate that hashCode and equals does not fail.
-                //noinspection ResultOfMethodCallIgnored
-                r.hashCode();
-                //noinspection EqualsWithItself,ResultOfMethodCallIgnored
-                r.equals(r);
-            })
-                    .as("Recipe must be able to instantiate via RecipeLoader")
-                    .doesNotThrowAnyException();
+            // Skip RecipeLoader null-instantiation test for Kotlin recipes with required options,
+            // as Jackson's Kotlin module enforces non-nullability and will fail when trying to
+            // instantiate with null arguments. The serialization round-trip test above still
+            // validates that actual recipe instances work correctly.
+            if (!RewriteTestUtils.isKotlinRecipeWithRequiredOptions(recipe.getClass())) {
+                assertThatCode(() -> {
+                    Recipe r = new RecipeLoader(recipe.getClass().getClassLoader())
+                            .load(recipe.getClass(), null);
+                    // getRecipeList should not fail with default parameters from RecipeLoader.
+                    r.getRecipeList();
+                    // We add recipes to HashSet in some places, we need to validate that hashCode and equals does not fail.
+                    //noinspection ResultOfMethodCallIgnored
+                    r.hashCode();
+                    //noinspection EqualsWithItself,ResultOfMethodCallIgnored
+                    r.equals(r);
+                })
+                        .as("Recipe must be able to instantiate via RecipeLoader")
+                        .doesNotThrowAnyException();
+            }
             validateRecipeNameAndDescription(recipe);
             validateRecipeOptions(recipe);
         }
@@ -709,6 +717,30 @@ default void validateRecipeOptions(Recipe recipe) {
 }
 
 class RewriteTestUtils {
+
+    /**
+     * Checks if a Kotlin recipe class has required options that will fail when
+     * instantiated with null arguments via Jackson. This is because Jackson's
+     * Kotlin module enforces non-nullability for Kotlin classes.
+     * <p>
+     * This check only applies to Kotlin classes since Java classes can have
+     * null values for any parameter type.
+     */
+    static boolean isKotlinRecipeWithRequiredOptions(Class<?> recipeClass) {
+        for (Annotation a : recipeClass.getDeclaredAnnotations()) {
+            if ("kotlin.Metadata".equals(a.annotationType().getName())) {
+                // Check for @Option fields with required=true (which is the default)
+                for (Field field : recipeClass.getDeclaredFields()) {
+                    Option option = field.getAnnotation(Option.class);
+                    if (option != null && option.required()) {
+                        return true;
+                    }
+                }
+            }
+        }
+        return false;
+    }
+
     static boolean groupSourceSpecsByParser(List<Parser.Builder> parserBuilders, Map<Parser.Builder, List<SourceSpec<?>>> sourceSpecsByParser, SourceSpec<?> sourceSpec) {
         for (Map.Entry<Parser.Builder, List<SourceSpec<?>>> entry : sourceSpecsByParser.entrySet()) {
             if (entry.getKey().getSourceFileType().equals(sourceSpec.sourceFileType) && sourceSpec.getParser().getClass().isAssignableFrom(entry.getKey().getClass())) {