Fix local YAML recipe scanning to be recursive (#7437)

* Add witness test for recursive YAML recipe scanning

* Fix local YAML recipe scanning to be recursive

Author: kdvolder

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

@@ -39,6 +39,7 @@
 import java.util.*;
 import java.util.jar.JarEntry;
 import java.util.jar.JarFile;
+import java.util.stream.Stream;
 
 import static java.util.Collections.emptyList;
 import static java.util.Collections.emptyMap;
@@ -415,11 +416,14 @@ private static List<YamlResource> listYamlResourcesFromPath(Path path) {
         if (Files.isDirectory(path)) {
             Path rewriteDir = path.resolve("META-INF/rewrite");
             if (Files.isDirectory(rewriteDir)) {
-                try (DirectoryStream<Path> stream = Files.newDirectoryStream(rewriteDir, "*.{yml,yaml}")) {
-                    for (Path file : stream) {
-                        resources.add(new YamlResource(file.toUri(), () -> Files.newInputStream(file)));
-                    }
-                } catch (IOException ignored) {
+                try (Stream<Path> stream = Files.walk(rewriteDir)) {
+                    stream.filter(Files::isRegularFile)
+                          .filter(p -> {
+                              String name = p.getFileName().toString();
+                              return name.endsWith(".yml") || name.endsWith(".yaml");
+                          })
+                          .forEach(file -> resources.add(new YamlResource(file.toUri(), () -> Files.newInputStream(file))));
+                } catch (IOException | java.io.UncheckedIOException ignored) {
                 }
             }
         } else if (Files.isRegularFile(path)) {

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

@@ -72,4 +72,42 @@ void scanJarWithSeparateClassesAndResourcesDirs(@TempDir Path tempDir) throws Ex
         assertThat(recipe).isNotNull();
         assertThat(recipe.getName()).isEqualTo("com.example.TestRecipe");
     }
+
+    @Test
+    void scanYamlInSubdirectory(@TempDir Path tempDir) throws Exception {
+        Path resourcesDir = tempDir.resolve("resources");
+        Path metaInfSubdir = resourcesDir.resolve("META-INF/rewrite/subdir");
+        Files.createDirectories(metaInfSubdir);
+
+        Files.writeString(metaInfSubdir.resolve("recipe.yml"),
+            """
+            type: specs.openrewrite.org/v1beta/recipe
+            name: com.example.SubdirRecipe
+            displayName: Subdir Recipe
+            description: A test recipe in a subdir.
+            recipeList:
+              - org.openrewrite.text.ChangeText:
+                  toText: subdir
+            """);
+
+        List<Path> classpath = List.of(resourcesDir);
+        URL[] urls = classpath.stream()
+            .map(p -> {
+                try {
+                    return p.toUri().toURL();
+                } catch (Exception e) {
+                    throw new RuntimeException(e);
+                }
+            })
+            .toArray(URL[]::new);
+        ClassLoader cl = new URLClassLoader(urls, Recipe.class.getClassLoader());
+
+        Environment env = Environment.builder()
+            .scanJar(resourcesDir, classpath, cl)
+            .build();
+
+        Recipe recipe = env.activateRecipes("com.example.SubdirRecipe");
+        assertThat(recipe).isNotNull();
+        assertThat(recipe.getName()).isEqualTo("com.example.SubdirRecipe");
+    }
 }