Implemented the ability to del __dict__

hbina · hbina · commit e25d2b0dd4b3 · 2025-03-08T19:16:57.000+08:00
This PR is based on the work by key262yek. The original PR is here: RustPython#5509
diff --git a/vm/src/builtins/object.rs b/vm/src/builtins/object.rs
@@ -495,9 +495,14 @@ pub fn object_get_dict(obj: PyObjectRef, vm: &VirtualMachine) -> PyResult<PyDict
     obj.dict()
         .ok_or_else(|| vm.new_attribute_error("This object has no __dict__".to_owned()))
 }
-pub fn object_set_dict(obj: PyObjectRef, dict: PyDictRef, vm: &VirtualMachine) -> PyResult<()> {
+
+pub fn object_set_dict(
+    obj: PyObjectRef,
+    dict: PySetterValue<PyDictRef>,
+    vm: &VirtualMachine,
+) -> PyResult<()> {
     obj.set_dict(dict)
-        .map_err(|_| vm.new_attribute_error("This object has no __dict__".to_owned()))
+        .ok_or_else(|| vm.new_type_error("cannot delete __dict__".to_owned()))
 }
 
 pub fn init(ctx: &Context) {
diff --git a/vm/src/builtins/type.rs b/vm/src/builtins/type.rs
@@ -1272,7 +1272,11 @@ fn subtype_get_dict(obj: PyObjectRef, vm: &VirtualMachine) -> PyResult {
     Ok(ret)
 }
 
-fn subtype_set_dict(obj: PyObjectRef, value: PyObjectRef, vm: &VirtualMachine) -> PyResult<()> {
+fn subtype_set_dict(
+    obj: PyObjectRef,
+    value: PySetterValue<PyObjectRef>,
+    vm: &VirtualMachine,
+) -> PyResult<()> {
     let cls = obj.class();
     match find_base_dict_descr(cls, vm) {
         Some(descr) => {
@@ -1285,10 +1289,11 @@ fn subtype_set_dict(obj: PyObjectRef, value: PyObjectRef, vm: &VirtualMachine) -
                         cls.name()
                     ))
                 })?;
-            descr_set(&descr, obj, PySetterValue::Assign(value), vm)
+            descr_set(&descr, obj, value, vm)
         }
         None => {
-            object::object_set_dict(obj, value.try_into_value(vm)?, vm)?;
+            let dict = value.map(|s| s.try_into_value(vm)).transpose()?;
+            object::object_set_dict(obj, dict, vm)?;
             Ok(())
         }
     }
diff --git a/vm/src/object/core.rs b/vm/src/object/core.rs
@@ -25,6 +25,7 @@ use crate::{
         lock::{PyMutex, PyMutexGuard, PyRwLock},
         refcount::RefCount,
     },
+    function::PySetterValue,
     vm::VirtualMachine,
 };
 use itertools::Itertools;
@@ -711,14 +712,37 @@ impl PyObject {
 
     /// Set the dict field. Returns `Err(dict)` if this object does not have a dict field
     /// in the first place.
-    pub fn set_dict(&self, dict: PyDictRef) -> Result<(), PyDictRef> {
-        match self.instance_dict() {
-            Some(d) => {
+    pub fn set_dict(&self, dict: PySetterValue<PyDictRef>) -> Option<()> {
+        // NOTE(hanif) - So far, this is the only error condition that I know of so we can use Option
+        // for now.
+        if self.payload_is::<crate::builtins::function::PyFunction>() {
+            return None;
+        }
+
+        match (self.instance_dict(), dict) {
+            (Some(d), PySetterValue::Assign(dict)) => {
                 d.set(dict);
-                Ok(())
             }
-            None => Err(dict),
-        }
+            (None, PySetterValue::Assign(dict)) => {
+                // self.0.dict = Some(InstanceDict::new(dict));
+                unsafe {
+                    let ptr = self as *const _ as *mut PyObject;
+                    (*ptr).0.dict = Some(InstanceDict::new(dict));
+                }
+            }
+            (Some(_), PySetterValue::Delete) => {
+                // self.0.dict = None;
+                unsafe {
+                    let ptr = self as *const _ as *mut PyObject;
+                    (*ptr).0.dict = None;
+                }
+            }
+            (None, PySetterValue::Delete) => {
+                // NOTE(hanif) - noop?
+            }
+        };
+
+        Some(())
     }
 
     #[inline(always)]
