_io: port BytesIO and StringIO to interp level; objspace: two __getattribute__ deviations

pyre/bench/synth/closure_per_call.wasm.jitstats

@@ -3,7 +3,9 @@ descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=0
-guard_failures=470
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
+guard_failures=468
 internal_compile_panics=0
 loops_aborted=0
 loops_compiled=4

pyre/bench/synth/exception_traceback_frame_lineno.wasm.jitstats

@@ -3,7 +3,9 @@ descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=0
-guard_failures=820
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
+guard_failures=819
 internal_compile_panics=0
 loops_aborted=0
 loops_compiled=17

pyre/bench/synth/gc_iterator_source_drop.wasm.jitstats

@@ -3,7 +3,9 @@ descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=0
-guard_failures=613
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
+guard_failures=614
 internal_compile_panics=0
 loops_aborted=0
 loops_compiled=4

pyre/bench/synth/pickle_ctor_args.cranelift.jitstats

@@ -1,9 +1,11 @@
-bridges_compiled=1
+bridges_compiled=0
 descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=0
-guard_failures=201
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
+guard_failures=1
 internal_compile_panics=0
 loops_aborted=0
-loops_compiled=4
+loops_compiled=2

pyre/bench/synth/pickle_ctor_args.dynasm.jitstats

@@ -3,7 +3,9 @@ descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=0
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
 guard_failures=1
 internal_compile_panics=0
 loops_aborted=0
-loops_compiled=4
+loops_compiled=2

pyre/bench/synth/pickle_ctor_args.wasm.jitstats

@@ -3,7 +3,9 @@ descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=0
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
 guard_failures=1
 internal_compile_panics=0
 loops_aborted=0
-loops_compiled=4
+loops_compiled=2

pyre/bench/synth/pickle_terminal_raise_resume.cranelift.jitstats

@@ -3,7 +3,9 @@ descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=0
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
 guard_failures=656
 internal_compile_panics=0
 loops_aborted=1
-loops_compiled=36
+loops_compiled=31

pyre/bench/synth/pickle_terminal_raise_resume.dynasm.jitstats

@@ -3,7 +3,9 @@ descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=0
-guard_failures=463
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
+guard_failures=354
 internal_compile_panics=0
 loops_aborted=1
-loops_compiled=36
+loops_compiled=31

pyre/bench/synth/pickle_terminal_raise_resume.wasm.jitstats

@@ -3,7 +3,9 @@ descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=5
-guard_failures=464
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
+guard_failures=355
 internal_compile_panics=0
 loops_aborted=13
-loops_compiled=73
+loops_compiled=68

pyre/bench/synth/recursive_call_frame_relocation.wasm.jitstats

@@ -3,7 +3,9 @@ descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=0
-guard_failures=649
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
+guard_failures=648
 internal_compile_panics=0
 loops_aborted=0
 loops_compiled=3

pyre/bench/synth/type_metatype_method_call.cranelift.jitstats

@@ -3,6 +3,8 @@ descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=0
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
 guard_failures=1
 internal_compile_panics=0
 loops_aborted=0

pyre/bench/synth/type_metatype_method_call.dynasm.jitstats

@@ -3,6 +3,8 @@ descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=0
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
 guard_failures=1
 internal_compile_panics=0
 loops_aborted=0

pyre/bench/synth/type_metatype_method_call.wasm.jitstats

@@ -3,7 +3,9 @@ descr_set_absent=0
 descr_set_ambiguous=0
 descr_set_stale_absent=0
 fbw_rolled_back_with_effects=0
-guard_failures=2
+field_pos_attached_misplaced=0
+field_pos_spec_misplaced=0
+guard_failures=1
 internal_compile_panics=0
 loops_aborted=0
 loops_compiled=2

pyre/pyre-interpreter/src/baseobjspace.rs

@@ -5739,21 +5739,29 @@ fn getattr_str_impl(obj: PyObjectRef, name: &str, call_getattr: bool, suppress:
             // lookup without re-dispatching to the override.
             if let Some(w_metatype) = crate::typedef::r#type(obj) {
                 if let Some(slot) = getattribute_if_not_from_object(w_metatype.as_ptr()) {
-                    let name_obj = w_str_new(name);
-                    // objspace.py:666 — bind the metaclass `__getattribute__`
-                    // through `__get__` and call it with the attribute name.
-                    match get_and_call_function(slot, obj, w_metatype.as_ptr(), &[name_obj]) {
-                        Ok(v) => return Ok(v),
-                        Err(e) if e.kind == PyErrorKind::AttributeError => {
-                            return type_getattr_hook_or_err(
-                                obj,
-                                &[Some(w_metatype.as_ptr()), None],
-                                name,
-                                e,
-                                call_getattr,
-                            );
+                    // typeobject.py:811-828 `W_TypeObject.descr_getattribute`
+                    // is the body inlined by `object_getattr_miss` below. Keep
+                    // a metaclass override on the descriptor-call path, but do
+                    // not wrap and then unwrap an already validated name merely
+                    // to re-enter that same canonical body.
+                    if !is_type_getattribute_descr(slot) {
+                        let name_obj = w_str_new(name);
+                        // objspace.py:666 — bind the metaclass
+                        // `__getattribute__` through `__get__` and call it with
+                        // the attribute name.
+                        match get_and_call_function(slot, obj, w_metatype.as_ptr(), &[name_obj]) {
+                            Ok(v) => return Ok(v),
+                            Err(e) if e.kind == PyErrorKind::AttributeError => {
+                                return type_getattr_hook_or_err(
+                                    obj,
+                                    &[Some(w_metatype.as_ptr()), None],
+                                    name,
+                                    e,
+                                    call_getattr,
+                                );
+                            }
+                            Err(e) => return Err(e),
                         }
-                        Err(e) => return Err(e),
                     }
                 }
             }
@@ -6280,34 +6288,55 @@ pub(crate) unsafe fn object_delattr_surrogate(
     }
 }
 
-/// `raiseattrerror` for a lone-surrogate name.  descroperation.py:58-64
-/// renders the name with `%R` (its repr), so a lone surrogate prints as
-/// `\udcXX` rather than a lossy replacement char.  The repr already
-/// supplies the surrounding quotes (`format_wtf8_repr`), matching the
-/// `%R` substitution in `"'%T' object has no attribute %R"`.
+/// `raiseattrerror` for a lone-surrogate name. descroperation.py:58-64 keeps
+/// the original name object in the formatted AttributeError, so build the
+/// exception argument as WTF-8 instead of reducing it to a Rust string.
 fn attr_error_wtf8(obj: PyObjectRef, name: &Wtf8) -> PyError {
-    let tp_name = unsafe {
-        match crate::typedef::r#type(obj) {
-            Some(tp) => pyre_object::w_type_get_name(tp.as_ptr()).to_string(),
-            None => (*(*obj).ob_type).name.to_string(),
-        }
-    };
-    let name_repr = crate::display::format_wtf8_repr(name);
-    let mut err = PyError::new(
-        PyErrorKind::AttributeError,
-        format!("'{tp_name}' object has no attribute {name_repr}"),
+    let mut message = Wtf8Buf::from_string(format!(
+        "{} has no attribute '",
+        missing_attribute_subject(obj)
+    ));
+    message.push_wtf8(name);
+    message.push_wtf8(Wtf8::new("'"));
+
+    let _roots = pyre_object::gc_roots::push_roots();
+    let obj_slot = pyre_object::gc_roots::shadow_stack_len();
+    pyre_object::gc_roots::pin_root(obj);
+    let w_name = pyre_object::w_str_from_wtf8(name.to_wtf8_buf());
+    let name_slot = pyre_object::gc_roots::shadow_stack_len();
+    pyre_object::gc_roots::pin_root(w_name);
+    let exc = pyre_object::interp_exceptions::w_exception_new_wtf8(
+        pyre_object::interp_exceptions::ExcKind::AttributeError,
+        &message,
     );
-    err.w_name_context = pyre_object::w_str_from_wtf8(name.to_wtf8_buf());
-    err.w_obj_context = obj;
-    err
+    unsafe {
+        pyre_object::interp_exceptions::w_exception_set_name(
+            exc,
+            pyre_object::gc_roots::shadow_stack_get(name_slot),
+        );
+        pyre_object::interp_exceptions::w_exception_set_attr_obj(
+            exc,
+            pyre_object::gc_roots::shadow_stack_get(obj_slot),
+        );
+        PyError::from_exc_object(exc)
+    }
 }
 
 /// `object.__getattribute__` terminal — the default descriptor protocol
 /// without the user `__getattribute__` override check.
 pub fn object_getattribute(obj: PyObjectRef, name: &str) -> PyResult {
     unsafe {
-        if is_instance(obj) {
-            let w_type = w_instance_get_type(obj);
+        if is_instance(obj) || is_type(obj) {
+            // descroperation.py:88-112 `Object.descr__getattribute__` uses
+            // `space.lookup(w_obj, name)`, hence the receiver's class (the
+            // metatype for a type object), and reads only
+            // `w_obj.getdictvalue`, never the receiver type's own MRO.
+            let instance = is_instance(obj);
+            let w_type = if instance {
+                w_instance_get_type(obj)
+            } else {
+                crate::typedef::r#type(obj).map_or(PY_NULL, |p| p.as_ptr())
+            };
             let w_descr = lookup_in_type_where(w_type, name);
             if let Some(descr) = w_descr {
                 if is_data_descr(descr) {
@@ -6316,13 +6345,15 @@ pub fn object_getattribute(obj: PyObjectRef, name: &str) -> PyResult {
                     }
                 }
             }
-            // Instance dict is the sole authority for instance attributes:
-            // read the mapdict node directly (getdictvalue, mapdict.py:846-847)
-            // rather than materialising the MapDictStrategy `__dict__` view, which
-            // MapDictStrategy.getitem_str (mapdict.py:1168-1175) delegates to
-            // anyway.  No side-table fallback.
-            let value =
-                crate::objspace::std::mapdict::instance_node_getdictvalue(obj, Wtf8::new(name));
+            // The receiver namespace is the sole authority at this stage.
+            // Read a user instance's mapdict node directly (getdictvalue,
+            // mapdict.py:846-847); a type receiver uses only its canonical
+            // dictionary, which is the corresponding `getdictvalue` result.
+            let value = if instance {
+                crate::objspace::std::mapdict::instance_node_getdictvalue(obj, Wtf8::new(name))
+            } else {
+                crate::type_dict_lookup(obj, name)
+            };
             if let Some(value) = value {
                 return Ok(value);
             }
@@ -6339,7 +6370,7 @@ pub fn object_getattribute(obj: PyObjectRef, name: &str) -> PyResult {
                 }
                 return Ok(descr);
             }
-            if name == "__class__" {
+            if instance && name == "__class__" {
                 return Ok(w_type);
             }
             // descroperation.py:88 — object.__getattribute__ raises
@@ -6354,12 +6385,19 @@ pub fn object_getattribute(obj: PyObjectRef, name: &str) -> PyResult {
             ));
         }
     }
-    // Non-instance receiver (module, type, builtin object): the pure descriptor
-    // protocol with no `__getattr__` fallback — that belongs to space.getattr,
-    // not the bare object.__getattribute__ slot (descroperation.py:88).
+    // Remaining non-instance receivers (module and builtin objects): preserve
+    // their pure descriptor protocol with no `__getattr__` fallback — that
+    // belongs to space.getattr, not the bare object.__getattribute__ slot
+    // (descroperation.py:88).
     getattr_str_impl(obj, name, false, false)
 }
 
+/// typeobject.py:811-828 `W_TypeObject.descr_getattribute` — the canonical
+/// metatype-data-descriptor, class-MRO, metatype-non-data-descriptor lookup.
+pub(crate) fn type_getattribute(obj: PyObjectRef, name: &str) -> PyResult {
+    object_getattr_miss(obj, name, false)
+}
+
 /// module.py `Module.descr_getattribute` — run the object-default descriptor
 /// protocol, then the module-dict `__getattr__` hook on AttributeError.
 pub(crate) fn module_getattribute(obj: PyObjectRef, name: &str) -> PyResult {
@@ -9528,6 +9566,13 @@ unsafe fn is_object_getattribute_descr(w_descr: PyObjectRef) -> bool {
     }
 }
 
+/// `typeobject.py:1322` — identity anchor for the canonical
+/// `W_TypeObject.descr_getattribute` wrapper installed on `type`.
+unsafe fn is_type_getattribute_descr(w_descr: PyObjectRef) -> bool {
+    lookup_in_type_where(crate::typedef::w_type(), "__getattribute__")
+        .is_some_and(|d| std::ptr::eq(w_descr, d))
+}
+
 /// module.py `Module.descr_getattribute` is the default attribute slot for
 /// module objects.  Module subclasses inherit it unless they explicitly
 /// replace `__getattribute__`.
@@ -11727,17 +11772,7 @@ pub(crate) fn raiseattrerror(
             "'{tp_name}' object attribute '{name}' is read-only"
         ));
     }
-    let subject = unsafe {
-        if is_type(obj) {
-            format!("type object '{}'", pyre_object::w_type_get_name(obj))
-        } else {
-            let tp_name = match crate::typedef::r#type(obj) {
-                Some(tp) => pyre_object::w_type_get_name(tp.as_ptr()).to_string(),
-                None => (*(*obj).ob_type).name.to_string(),
-            };
-            format!("'{}' object", tp_name)
-        }
-    };
+    let subject = missing_attribute_subject(obj);
     // `object.c _PyObject_GenericSetAttrWithDict` appends the suffix when the
     // receiver has no dict *slot*.  A raising `getdict` says nothing about
     // whether the object could hold a dict, so the suffix is only added on a
@@ -11754,6 +11789,20 @@ pub(crate) fn raiseattrerror(
     )
 }
 
+fn missing_attribute_subject(obj: PyObjectRef) -> String {
+    unsafe {
+        if is_type(obj) {
+            format!("type object '{}'", pyre_object::w_type_get_name(obj))
+        } else {
+            let tp_name = match crate::typedef::r#type(obj) {
+                Some(tp) => pyre_object::w_type_get_name(tp.as_ptr()).to_string(),
+                None => (*(*obj).ob_type).name.to_string(),
+            };
+            format!("'{tp_name}' object")
+        }
+    }
+}
+
 /// Delete an attribute: `del obj.name`.
 ///
 /// PyPy: descroperation.py descr__delattr__

pyre/pyre-interpreter/src/lib.rs

@@ -1072,6 +1072,10 @@ pub fn all_subclass_range_aliases() -> Vec<pyre_object::pyobject::SubclassRangeA
             158,
             typed::<crate::module::__pypy__::interp_buffer::bufferable_impl::W_Bufferable>(),
         ),
+        // `_io.BytesIO` registers after the `rbigint` result pair, which takes
+        // 159 as a bare `with_gc_ptrs` id and carries no vtable of its own.
+        subclass_range_alias(160, typed::<crate::module::_io::W_BytesIO>()),
+        subclass_range_alias(161, typed::<crate::module::_io::W_StringIO>()),
     ]
 }