Fix AnnotationTemplateGenerator to handle nested annotations correctly (#5713)

* Fix `AnnotationTemplateGenerator` to handle nested annotations correctly

The `AnnotationTemplateGenerator` was failing with an `IndexOutOfBoundsException` when processing nested
annotations (e.g., repeatable annotations within annotation arrays). This occurred because the template
generator couldn't find a "typical annotation target" for annotations nested inside other annotations' array
values.

The fix adds proper handling for nested annotations by:
1. Walking up the parent hierarchy to find the ultimate annotation target (method, variable, or class)
2. Adding a fallback case that generates `@interface $Placeholder {}` when no typical target can be found
3. Updating both the `template()` and `cacheKey()` methods to handle nested annotation cases consistently

This ensures that `JavaTemplate` can successfully process and transform nested annotations without throwing
exceptions.

Added a test case that demonstrates the fix by transforming nested repeatable annotations' attributes using
`JavaTemplate`.

Fixes:
- #5712

* Remove unnecessary code

* Remove need for `TypeValidation.none()`

* Trim empty lines

* Trim empty lines

* Remove unnecessary branch

---------

Co-authored-by: Tim te Beek <tim@moderne.io>

Author: knutwannheden

.claude/settings.local.json

@@ -9,10 +9,14 @@
       "Bash(grep:*)",
       "Bash(mv:*)",
       "Bash(npm test:*)",
+      "Bash(rg:*)",
       "Bash(rm:*)",
       "Bash(timeout:*)",
       "WebFetch(domain:github.com)",
       "mcp__github__get_issue",
+      "mcp__github__get_issue_comments",
+      "mcp__github__get_pull_request",
+      "mcp__github__get_pull_request_comments",
       "mcp__idea__find_files_by_name_substring",
       "mcp__idea__get_file_text_by_path",
       "mcp__idea__get_open_in_editor_file_path",

rewrite-java-test/src/test/java/org/openrewrite/java/JavaTemplateAnnotationTest.java

@@ -15,6 +15,7 @@
  */
 package org.openrewrite.java;
 
+import org.intellij.lang.annotations.Language;
 import org.junit.jupiter.api.Test;
 import org.openrewrite.DocumentExample;
 import org.openrewrite.ExecutionContext;
@@ -158,4 +159,75 @@ public record Person(
           )
         );
     }
+
+    @Issue("https://github.com/openrewrite/rewrite/issues/5712")
+    @Test
+    void replaceArgumentsInNestedAnnotation() {
+        @Language("java")
+        String annotations = """
+          package foo;
+
+          import java.lang.annotation.*;
+
+          @Repeatable(NestedAnnotations.class)
+          public @interface NestedAnnotation {
+              String a() default "";
+              String b() default "";
+          }
+
+          public @interface NestedAnnotations {
+              NestedAnnotation[] value();
+          }
+          """;
+        rewriteRun(
+          spec -> spec
+            .parser(JavaParser.fromJavaVersion().dependsOn(annotations))
+            .recipe(toRecipe(() -> new JavaIsoVisitor<>() {
+                @Override
+                public J.Annotation visitAnnotation(J.Annotation annotation, ExecutionContext ctx) {
+                    if (annotation.getSimpleName().equals("NestedAnnotation") &&
+                      !annotation.getArguments().isEmpty()) {
+                        // Check if this annotation still has the 'a' attribute that needs to be replaced
+                        J.Assignment arg = (J.Assignment) annotation.getArguments().get(0);
+                        if (arg.getVariable() instanceof J.Identifier &&
+                          ((J.Identifier) arg.getVariable()).getSimpleName().equals("a")) {
+                            // Only apply the template if we haven't already transformed this annotation
+                            J.Literal value = (J.Literal) arg.getAssignment();
+
+                            // Replace 'a' with 'b' in the annotation
+                            return JavaTemplate.builder("@NestedAnnotation(b = #{any(java.lang.String)})")
+                              .javaParser(JavaParser.fromJavaVersion().dependsOn(annotations))
+                              .imports("foo.*")
+                              .build()
+                              .apply(getCursor(), annotation.getCoordinates().replace(), value);
+                        }
+                    }
+                    return super.visitAnnotation(annotation, ctx);
+                }
+            })),
+          java(
+            """
+              import foo.*;
+
+              @NestedAnnotations({
+                      @NestedAnnotation(a = "1"),
+                      @NestedAnnotation(a = "2")
+              })
+              class Test {
+              }
+              """,
+            """
+              import foo.*;
+
+              @NestedAnnotations({
+                      @NestedAnnotation(b = "1"),
+                      @NestedAnnotation(b = "2")
+              })
+              class Test {
+              }
+              """
+          )
+        );
+    }
+
 }

rewrite-java/src/main/java/org/openrewrite/java/internal/template/AnnotationTemplateGenerator.java

@@ -89,8 +89,10 @@ public String template(Cursor cursor, String template) {
                         after.insert(0, " void $method() {}");
                     } else if (j instanceof J.VariableDeclarations || annotationParent instanceof J.VariableDeclarations) {
                         after.insert(0, " int $variable;");
-                    } else if (j instanceof J.ClassDeclaration) {
-                        if (cursor.getParentOrThrow().getValue() instanceof JavaSourceFile) {
+                    } else if (j instanceof J.ClassDeclaration || annotationParent instanceof J.ClassDeclaration) {
+                        // Check if this is a top-level class or nested class
+                        Cursor classCursor = j instanceof J.ClassDeclaration ? cursor : cursor.getParent(level);
+                        if (classCursor != null && classCursor.getParentOrThrow().getValue() instanceof JavaSourceFile) {
                             after.insert(0, "class $Clazz {}");
                         } else {
                             after.insert(0, "static class $Clazz {}");

rewrite-java/src/main/java/org/openrewrite/java/internal/template/JavaTemplateJavaExtension.java

@@ -57,7 +57,7 @@ public TreeVisitor<? extends J, Integer> getMixin() {
             private boolean substituted;
 
             @Override
-            public J visitAnnotation(J.Annotation annotation, Integer integer) {
+            public J visitAnnotation(J.Annotation annotation, Integer p) {
                 if (loc == ANNOTATION_PREFIX && mode == JavaCoordinates.Mode.REPLACEMENT &&
                     isScope(annotation)) {
                     List<J.Annotation> gen = unsubstitute(templateParser.parseAnnotations(getCursor(), substitutedTemplate));
@@ -66,14 +66,14 @@ public J visitAnnotation(J.Annotation annotation, Integer integer) {
                                                         substitutedTemplate +
                                                         "\nUse JavaTemplate.Builder.doBeforeParseTemplate() to see what stub is being generated and include it in any bug report.");
                     }
-                    return gen.get(0).withPrefix(annotation.getPrefix());
+                    return autoFormat(gen.get(0).withPrefix(annotation.getPrefix()), p, getCursor().getParentOrThrow());
                 } else if (loc == ANNOTATION_ARGUMENTS && mode == JavaCoordinates.Mode.REPLACEMENT &&
                            isScope(annotation)) {
                     List<J.Annotation> gen = unsubstitute(templateParser.parseAnnotations(getCursor(), "@Example(" + substitutedTemplate + ")"));
                     return annotation.withArguments(gen.get(0).getArguments());
                 }
 
-                return super.visitAnnotation(annotation, integer);
+                return super.visitAnnotation(annotation, p);
             }
 
             @Override