__hash__ to slot_wrapper (#6480)

crates/vm/src/builtins/descriptor.rs

@@ -6,7 +6,8 @@ use crate::{
     common::hash::PyHash,
     function::{FuncArgs, PyMethodDef, PyMethodFlags, PySetterValue},
     types::{
-        Callable, Comparable, GetDescriptor, Hashable, InitFunc, PyComparisonOp, Representable,
+        Callable, Comparable, GetDescriptor, HashFunc, Hashable, InitFunc, PyComparisonOp,
+        Representable,
     },
 };
 use rustpython_common::lock::PyRwLock;
@@ -391,6 +392,44 @@ pub fn init(ctx: &Context) {
 
 // PySlotWrapper - wrapper_descriptor
 
+/// Type-erased slot function - mirrors CPython's void* d_wrapped
+/// Each variant knows how to call the wrapped function with proper types
+#[derive(Clone, Copy)]
+pub enum SlotFunc {
+    Init(InitFunc),
+    Hash(HashFunc),
+}
+
+impl std::fmt::Debug for SlotFunc {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            SlotFunc::Init(_) => write!(f, "SlotFunc::Init(...)"),
+            SlotFunc::Hash(_) => write!(f, "SlotFunc::Hash(...)"),
+        }
+    }
+}
+
+impl SlotFunc {
+    /// Call the wrapped slot function with proper type handling
+    pub fn call(&self, obj: PyObjectRef, args: FuncArgs, vm: &VirtualMachine) -> PyResult {
+        match self {
+            SlotFunc::Init(func) => {
+                func(obj, args, vm)?;
+                Ok(vm.ctx.none())
+            }
+            SlotFunc::Hash(func) => {
+                if !args.args.is_empty() || !args.kwargs.is_empty() {
+                    return Err(
+                        vm.new_type_error("__hash__() takes no arguments (1 given)".to_owned())
+                    );
+                }
+                let hash = func(&obj, vm)?;
+                Ok(vm.ctx.new_int(hash).into())
+            }
+        }
+    }
+}
+
 /// wrapper_descriptor: wraps a slot function as a Python method
 // = PyWrapperDescrObject
 #[pyclass(name = "wrapper_descriptor", module = false)]
@@ -398,7 +437,7 @@ pub fn init(ctx: &Context) {
 pub struct PySlotWrapper {
     pub typ: &'static Py<PyType>,
     pub name: &'static PyStrInterned,
-    pub wrapped: InitFunc,
+    pub wrapped: SlotFunc,
     pub doc: Option<&'static str>,
 }
 
@@ -430,7 +469,7 @@ impl Callable for PySlotWrapper {
     type Args = FuncArgs;
 
     fn call(zelf: &Py<Self>, args: FuncArgs, vm: &VirtualMachine) -> PyResult {
-        // list.__init__(l, [1,2,3]) form
+        // list.__init__(l, [1,2,3]) form - first arg is self
         let (obj, rest): (PyObjectRef, FuncArgs) = args.bind(vm)?;
 
         if !obj.fast_isinstance(zelf.typ) {
@@ -442,8 +481,7 @@ impl Callable for PySlotWrapper {
             )));
         }
 
-        (zelf.wrapped)(obj, rest, vm)?;
-        Ok(vm.ctx.none())
+        zelf.wrapped.call(obj, rest, vm)
     }
 }
 
@@ -506,8 +544,7 @@ impl Callable for PyMethodWrapper {
     type Args = FuncArgs;
 
     fn call(zelf: &Py<Self>, args: FuncArgs, vm: &VirtualMachine) -> PyResult {
-        (zelf.wrapper.wrapped)(zelf.obj.clone(), args, vm)?;
-        Ok(vm.ctx.none())
+        zelf.wrapper.wrapped.call(zelf.obj.clone(), args, vm)
     }
 }
 

crates/vm/src/class.rs

@@ -2,7 +2,10 @@
 
 use crate::{
     PyPayload,
-    builtins::{PyBaseObject, PyType, PyTypeRef, descriptor::PySlotWrapper},
+    builtins::{
+        PyBaseObject, PyType, PyTypeRef,
+        descriptor::{PySlotWrapper, SlotFunc},
+    },
     function::PyMethodDef,
     object::Py,
     types::{PyTypeFlags, PyTypeSlots, hash_not_implemented},
@@ -143,13 +146,30 @@ pub trait PyClassImpl: PyClassDef {
                 let wrapper = PySlotWrapper {
                     typ: class,
                     name: ctx.intern_str("__init__"),
-                    wrapped: init_func,
+                    wrapped: SlotFunc::Init(init_func),
                     doc: Some("Initialize self. See help(type(self)) for accurate signature."),
                 };
                 class.set_attr(init_name, wrapper.into_ref(ctx).into());
             }
         }
 
+        // Add __hash__ slot wrapper if slot exists and not already in dict
+        // Note: hash_not_implemented is handled separately (sets __hash__ = None)
+        if let Some(hash_func) = class.slots.hash.load()
+            && hash_func as usize != hash_not_implemented as usize
+        {
+            let hash_name = identifier!(ctx, __hash__);
+            if !class.attributes.read().contains_key(hash_name) {
+                let wrapper = PySlotWrapper {
+                    typ: class,
+                    name: ctx.intern_str("__hash__"),
+                    wrapped: SlotFunc::Hash(hash_func),
+                    doc: Some("Return hash(self)."),
+                };
+                class.set_attr(hash_name, wrapper.into_ref(ctx).into());
+            }
+        }
+
         if class.slots.hash.load().map_or(0, |h| h as usize) == hash_not_implemented as usize {
             class.set_attr(ctx.names.__hash__, ctx.none.clone().into());
         }

crates/vm/src/types/slot.rs

@@ -1098,11 +1098,7 @@ pub trait Hashable: PyPayload {
         Self::hash(zelf, vm)
     }
 
-    #[inline]
-    #[pymethod]
-    fn __hash__(zelf: PyObjectRef, vm: &VirtualMachine) -> PyResult<PyHash> {
-        Self::slot_hash(&zelf, vm)
-    }
+    // __hash__ is now exposed via SlotFunc::Hash wrapper in extend_class()
 
     fn hash(zelf: &Py<Self>, vm: &VirtualMachine) -> PyResult<PyHash>;
 }