ruby · tagomoris · Jun 15, 2025 · Jun 22, 2025 · Jun 22, 2025 · Jun 22, 2025
diff --git a/builtin.c b/builtin.c
@@ -50,17 +50,8 @@ load_with_builtin_functions(const char *feature_name, const struct rb_builtin_fu
     ASSUME(iseq); // otherwise an exception should have raised
     vm->builtin_function_table = NULL;
 
-    rb_namespace_enable_builtin();
-
     // exec
-    if (rb_namespace_available() && rb_mNamespaceRefiner) {
-        rb_iseq_eval_with_refinement(rb_iseq_check(iseq), rb_mNamespaceRefiner);
-    }
-    else {
-        rb_iseq_eval(rb_iseq_check(iseq));
-    }
-
-    rb_namespace_disable_builtin();
+    rb_iseq_eval(rb_iseq_check(iseq), rb_root_namespace()); // builtin functions are loaded in the root namespace
 }
 
 void

diff --git a/class.c b/class.c
@@ -648,7 +648,7 @@ class_alloc0(enum ruby_value_type type, VALUE klass, bool namespaceable)
 {
     rb_ns_subclasses_t *ns_subclasses;
     rb_subclass_anchor_t *anchor;
-    const rb_namespace_t *ns = rb_definition_namespace();
+    const rb_namespace_t *ns = rb_current_namespace();
 
     if (!ruby_namespace_init_done) {
         namespaceable = true;

diff --git a/eval.c b/eval.c
@@ -80,6 +80,7 @@ ruby_setup(void)
     rb_vm_encoded_insn_data_table_init();
     Init_enable_namespace();
     Init_vm_objects();
+    Init_root_namespace();
     Init_fstring_table();
 
     EC_PUSH_TAG(GET_EC());

diff --git a/eval_intern.h b/eval_intern.h
@@ -296,7 +296,11 @@ VALUE rb_vm_make_jump_tag_but_local_jump(enum ruby_tag_type state, VALUE val);
 rb_cref_t *rb_vm_cref(void);
 rb_cref_t *rb_vm_cref_replace_with_duplicated_cref(void);
 VALUE rb_vm_call_cfunc(VALUE recv, VALUE (*func)(VALUE), VALUE arg, VALUE block_handler, VALUE filename);
-VALUE rb_vm_call_cfunc2(VALUE recv, VALUE (*func)(VALUE, VALUE), VALUE arg1, VALUE arg2, VALUE block_handler, VALUE filename);
+VALUE rb_vm_call_cfunc_in_namespace(VALUE recv, VALUE (*func)(VALUE, VALUE), VALUE arg1, VALUE arg2, VALUE filename, const rb_namespace_t *ns);
+void rb_vm_frame_flag_set_ns_require(const rb_execution_context_t *ec);
+const rb_namespace_t *rb_vm_current_namespace(const rb_execution_context_t *ec);
+const rb_namespace_t *rb_vm_caller_namespace(const rb_execution_context_t *ec);
+const rb_namespace_t *rb_vm_loading_namespace(const rb_execution_context_t *ec);
 void rb_vm_set_progname(VALUE filename);
 VALUE rb_vm_cbase(void);
 

diff --git a/inits.c b/inits.c
@@ -52,6 +52,7 @@ rb_call_inits(void)
     CALL(Time);
     CALL(Random);
     CALL(load);
+    CALL(Namespace);
     CALL(Proc);
     CALL(Binding);
     CALL(Math);
@@ -77,7 +78,6 @@ rb_call_inits(void)
     CALL(Prism);
     CALL(unicode_version);
     CALL(Set);
-    CALL(Namespace);
 
     // enable builtin loading
     CALL(builtin);

diff --git a/insns.def b/insns.def
@@ -802,12 +802,13 @@ defineclass
 (VALUE val)
 {
     VALUE klass = vm_find_or_create_class_by_id(id, flags, cbase, super);
+    const rb_namespace_t *ns = rb_current_namespace();
 
     rb_iseq_check(class_iseq);
 
     /* enter scope */
     vm_push_frame(ec, class_iseq, VM_FRAME_MAGIC_CLASS | VM_ENV_FLAG_LOCAL, klass,
-                  GET_BLOCK_HANDLER(),
+                  GC_GUARDED_PTR(ns),
                   (VALUE)vm_cref_push(ec, klass, NULL, FALSE, FALSE),
                   ISEQ_BODY(class_iseq)->iseq_encoded, GET_SP(),
                   ISEQ_BODY(class_iseq)->local_table_size,

diff --git a/internal/class.h b/internal/class.h
@@ -393,8 +393,7 @@ RCLASS_EXT_READABLE_LOOKUP(VALUE obj, const rb_namespace_t *ns)
 static inline rb_classext_t *
 RCLASS_EXT_READABLE_IN_NS(VALUE obj, const rb_namespace_t *ns)
 {
-    if (!ns
-        || NAMESPACE_BUILTIN_P(ns)
+    if (NAMESPACE_ROOT_P(ns)
         || RCLASS_PRIME_CLASSEXT_READABLE_P(obj)) {
         return RCLASS_EXT_PRIME(obj);
     }
@@ -408,9 +407,9 @@ RCLASS_EXT_READABLE(VALUE obj)
     if (RCLASS_PRIME_CLASSEXT_READABLE_P(obj)) {
         return RCLASS_EXT_PRIME(obj);
     }
-    // delay namespace loading to optimize for unmodified classes
+    // delay determining the current namespace to optimize for unmodified classes
     ns = rb_current_namespace();
-    if (!ns || NAMESPACE_BUILTIN_P(ns)) {
+    if (NAMESPACE_ROOT_P(ns)) {
         return RCLASS_EXT_PRIME(obj);
     }
     return RCLASS_EXT_READABLE_LOOKUP(obj, ns);
@@ -443,8 +442,7 @@ RCLASS_EXT_WRITABLE_LOOKUP(VALUE obj, const rb_namespace_t *ns)
 static inline rb_classext_t *
 RCLASS_EXT_WRITABLE_IN_NS(VALUE obj, const rb_namespace_t *ns)
 {
-    if (!ns
-        || NAMESPACE_BUILTIN_P(ns)
+    if (NAMESPACE_ROOT_P(ns)
         || RCLASS_PRIME_CLASSEXT_WRITABLE_P(obj)) {
         return RCLASS_EXT_PRIME(obj);
     }
@@ -458,11 +456,9 @@ RCLASS_EXT_WRITABLE(VALUE obj)
     if (LIKELY(RCLASS_PRIME_CLASSEXT_WRITABLE_P(obj))) {
         return RCLASS_EXT_PRIME(obj);
     }
-    // delay namespace loading to optimize for unmodified classes
+    // delay determining the current namespace to optimize for unmodified classes
     ns = rb_current_namespace();
-    if (!ns || NAMESPACE_BUILTIN_P(ns)) {
-        // If no namespace is specified, Ruby VM is in bootstrap
-        // and the clean class definition is under construction.
+    if (NAMESPACE_ROOT_P(ns)) {
         return RCLASS_EXT_PRIME(obj);
     }
     return RCLASS_EXT_WRITABLE_LOOKUP(obj, ns);

diff --git a/internal/inits.h b/internal/inits.h
@@ -32,6 +32,9 @@ void Init_enable_namespace(void);
 void Init_BareVM(void);
 void Init_vm_objects(void);
 
+/* namespace.c */
+void Init_root_namespace(void);
+
 /* vm_backtrace.c */
 void Init_vm_backtrace(void);
 

diff --git a/internal/namespace.h b/internal/namespace.h
@@ -35,13 +35,14 @@ struct rb_namespace_struct {
 
     VALUE gvar_tbl;
 
-    bool is_builtin;
     bool is_user;
     bool is_optional;
 };
 typedef struct rb_namespace_struct rb_namespace_t;
 
-#define NAMESPACE_BUILTIN_P(ns) (ns && ns->is_builtin)
+#define NAMESPACE_OBJ_P(obj) (rb_obj_class(obj) == rb_cNamespace)
+
+#define NAMESPACE_ROOT_P(ns) (ns && !ns->is_user)
 #define NAMESPACE_USER_P(ns) (ns && ns->is_user)
 #define NAMESPACE_OPTIONAL_P(ns) (ns && ns->is_optional)
 #define NAMESPACE_MAIN_P(ns) (ns && ns->is_user && !ns->is_optional)
@@ -60,24 +61,16 @@ rb_namespace_available(void)
     return ruby_namespace_enabled;
 }
 
-void rb_namespace_enable_builtin(void);
-void rb_namespace_disable_builtin(void);
-void rb_namespace_push_loading_namespace(const rb_namespace_t *);
-void rb_namespace_pop_loading_namespace(const rb_namespace_t *);
-rb_namespace_t * rb_root_namespace(void);
-const rb_namespace_t *rb_builtin_namespace(void);
-rb_namespace_t * rb_main_namespace(void);
-const rb_namespace_t * rb_definition_namespace(void);
-const rb_namespace_t * rb_loading_namespace(void);
+const rb_namespace_t * rb_root_namespace(void);
+const rb_namespace_t * rb_main_namespace(void);
 const rb_namespace_t * rb_current_namespace(void);
-VALUE rb_current_namespace_details(VALUE);
+const rb_namespace_t * rb_loading_namespace(void);
 
 void rb_namespace_entry_mark(void *);
+void rb_namespace_gc_update_references(void *ptr);
 
 rb_namespace_t * rb_get_namespace_t(VALUE ns);
 VALUE rb_get_namespace_object(rb_namespace_t *ns);
-typedef VALUE namespace_exec_func(VALUE arg);
-VALUE rb_namespace_exec(const rb_namespace_t *ns, namespace_exec_func *func, VALUE arg);
 
 VALUE rb_namespace_local_extension(VALUE namespace, VALUE fname, VALUE path);
 

diff --git a/iseq.c b/iseq.c
@@ -1950,7 +1950,7 @@ iseqw_eval(VALUE self)
     if (0 == ISEQ_BODY(iseq)->iseq_size) {
         rb_raise(rb_eTypeError, "attempt to evaluate dummy InstructionSequence");
     }
-    return rb_iseq_eval(iseq);
+    return rb_iseq_eval(iseq, rb_current_namespace());
 }
 
 /*