fix(extract): prevent duplicate Function nodes for Java interface methods (#1234)

internal/cbm/extract_defs.c

@@ -6269,6 +6269,7 @@ static void push_class_body_children(TSNode node, const CBMLangSpec *spec, wd_st
         if (strcmp(ck, "field_declaration_list") == 0 || strcmp(ck, "class_body") == 0 ||
             strcmp(ck, "declaration_list") == 0 || strcmp(ck, "body") == 0 ||
             strcmp(ck, "block") == 0 || strcmp(ck, "suite") == 0 ||
+            strcmp(ck, "interface_body") == 0 || strcmp(ck, "enum_body") == 0 ||
             // Groovy class bodies are a `closure` node; routing through the
             // nested-class path keeps methods from being re-walked (and thus
             // double-extracted) as top-level functions. Gated to Groovy so other

tests/test_extraction.c

@@ -419,6 +419,35 @@ TEST(java_interface) {
     PASS();
 }
 
+/* Regression for #1234: Java interface methods were emitted as both a Method
+ * node (correct, via extract_class_methods) and a duplicate Function node
+ * (incorrect, via the walk_defs fallback). push_class_body_children did not
+ * recognize interface_body as a class body container, so method_declaration
+ * children were re-walked and extracted as top-level functions. */
+TEST(java_interface_no_duplicate_function_issue1234) {
+    CBMFileResult *r =
+        extract("public interface MarketplaceService {\n"
+                "    ReservationDTO createReservation(Authentication auth, RequestDTO req);\n"
+                "    void cancelReservation(long id);\n"
+                "}\n",
+                CBM_LANG_JAVA, "t", "MarketplaceService.java");
+    ASSERT_NOT_NULL(r);
+    ASSERT_FALSE(r->has_error);
+
+    /* The interface itself must exist. */
+    ASSERT(has_def(r, "Interface", "MarketplaceService"));
+
+    /* Each method must be a Method, not a Function. */
+    ASSERT(has_def(r, "Method", "createReservation"));
+    ASSERT(has_def(r, "Method", "cancelReservation"));
+
+    /* No Function nodes should exist for interface methods. */
+    ASSERT_EQ(count_defs_with_label(r, "Function"), 0);
+
+    cbm_free_result(r);
+    PASS();
+}
+
 /* Regression for #279: a Java class declaring both `extends` and
  * `implements` must produce one INHERITS edge per base — the extends parent
  * AND every implements interface — with bare type names (not the keyword
@@ -4766,6 +4795,7 @@ SUITE(extraction) {
     RUN_TEST(java_class);
     RUN_TEST(java_method);
     RUN_TEST(java_interface);
+    RUN_TEST(java_interface_no_duplicate_function_issue1234);
     RUN_TEST(java_class_extends_and_implements);
     RUN_TEST(python_class_base_extracted_bare);
     RUN_TEST(php_class);