youknowone · Oct 15, 2026 · Oct 14, 2026 · chatgpt-codex-connector · Oct 15, 2026
diff --git a/crates/stdlib/src/json.rs b/crates/stdlib/src/json.rs
@@ -5,7 +5,8 @@ mod _json {
     use crate::vm::{
         AsObject, Py, PyObject, PyObjectRef, PyPayload, PyResult, VirtualMachine,
         builtins::{
-            PyBaseExceptionRef, PyDict, PyFloat, PyInt, PyList, PyStr, PyStrRef, PyTuple, PyType,
+            PyAnyDict, PyBaseExceptionRef, PyDict, PyFloat, PyInt, PyList, PyStr, PyStrRef,
+            PyTuple, PyType,
         },
         convert::ToPyResult,
         function::{IntoFuncArgs, OptionalArg},
@@ -1126,18 +1127,20 @@ mod _json {
             Ok(())
         }
 
-        /// Fetch `dct.items()` for encoding. For an exact `dict` this reads
+        /// Fetch `dct.items()` for encoding. For an exact `dict` or `frozendict` this reads
         /// the native table directly (matching CPython's fast path); for a
-        /// `dict` subclass (e.g. `collections.OrderedDict`) it calls the
+        /// subclass (e.g. `collections.OrderedDict`) it calls the
         /// real (possibly overridden) `.items()` method instead, so a
         /// subclass's custom ordering/behavior is respected.
         fn dict_items(
             &self,
             obj: &PyObject,
-            dict: &Py<PyDict>,
+            dict: &PyAnyDict,
             vm: &VirtualMachine,
         ) -> PyResult<Vec<(PyObjectRef, PyObjectRef)>> {
-            if obj.class().is(vm.ctx.types.dict_type) {
+            if obj.class().is(vm.ctx.types.dict_type)
+                || obj.class().is(vm.ctx.types.frozendict_type)
+            {
                 return Ok(dict.items_vec());
             }
             let items_obj = obj.get_attr("items", vm)?.call((), vm)?;
@@ -1155,7 +1158,7 @@ mod _json {
         fn encode_dict(
             &self,
             obj: &PyObject,
-            dict: &Py<PyDict>,
+            dict: &PyAnyDict,
             level: isize,
             out: &mut Wtf8Buf,
             vm: &VirtualMachine,
@@ -1289,7 +1292,7 @@ mod _json {
                 } else if let Some(tuple) = obj.downcast_ref::<PyTuple>() {
                     let slice = tuple.as_slice();
                     self.encode_list(obj, level, out, vm, || slice.len(), |i| slice[i].clone())
-                } else if let Some(dict) = obj.downcast_ref::<PyDict>() {
+                } else if let Some(dict) = PyAnyDict::from_object(obj) {
                     self.encode_dict(obj, dict, level, out, vm)
                 } else {
                     self.encode_default(obj, level, out, vm)

diff --git a/crates/vm/src/builtins/mappingproxy.rs b/crates/vm/src/builtins/mappingproxy.rs
@@ -2,12 +2,13 @@ use super::{PyDict, PyDictRef, PyGenericAlias, PyList, PyTuple, PyType, PyTypeRe
 use crate::{
     AsObject, Context, Py, PyObject, PyObjectRef, PyPayload, PyRef, PyResult, VirtualMachine,
     atomic_func,
-    class::PyClassImpl,
+    class::{PyClassImpl, StaticType},
     common::{hash, lock::LazyLock},
     convert::ToPyObject,
     function::{ArgMapping, Either, OptionalArg, PyComparisonValue},
     object::{Traverse, TraverseFn},
     protocol::{PyMappingMethods, PyNumberMethods, PySequenceMethods},
+    stdlib::PyOrderedDict,
     types::{
         AsMapping, AsNumber, AsSequence, Constructor, Hashable, Iterable, PyComparisonOp,
         Representable,
@@ -202,8 +203,24 @@ impl Py<PyMappingProxy> {
         if !matches!(op, PyComparisonOp::Eq | PyComparisonOp::Ne) {
             return Ok(Either::B(PyComparisonValue::NotImplemented));
         }
-        let obj = zelf.to_object(vm)?;
-        // Equality comparisons preserve the underlying mapping's result.
+        let mut obj = zelf.to_object(vm)?;
+        // Unknown comparison methods must not receive a mutable dictionary
+        // protected by the proxy. Class namespaces are already copied by
+        // to_object; other exact dicts need the same protection here.
+        if matches!(&zelf.mapping, MappingProxyInner::Mapping(_))
+            && obj.class().is(vm.ctx.types.dict_type)
+            && !(other.class().is(vm.ctx.types.dict_type)
+                || other.class().is(vm.ctx.types.frozendict_type)
+                || other.class().is(vm.ctx.types.mappingproxy_type)
+                || (other.downcastable::<PyOrderedDict>()
+                    && other.class().is(PyOrderedDict::static_type())))
+        {
+            obj = obj
+                .downcast_ref::<PyDict>()
+                .unwrap()
+                .copy()
+                .into_pyobject(vm);
+        }
         obj.rich_compare(other.to_owned(), op, vm).map(Either::A)
     }
 

diff --git a/crates/vm/src/builtins/str.rs b/crates/vm/src/builtins/str.rs
@@ -1,5 +1,6 @@
 use super::{
-    PositionIterInternal, PyBytesRef, PyDict, PyList, PyTuple, PyTupleRef, PyType, PyTypeRef,
+    PositionIterInternal, PyAnyDict, PyBytesRef, PyDict, PyList, PyTuple, PyTupleRef, PyType,
+    PyTypeRef,
     int::PyInt,
     iter::{IterStatus, builtins_iter},
 };
@@ -1580,17 +1581,15 @@ impl Py<PyStr> {
                 )),
             }
         } else {
-            // dict_str must be a dict
-            match dict_or_str.downcast::<PyDict>() {
-                Ok(dict) => {
+            // The single-argument form accepts exact dict and frozendict objects.
+            match PyAnyDict::from_object(&dict_or_str).filter(|_| {
+                dict_or_str.class().is(vm.ctx.types.dict_type)
+                    || dict_or_str.class().is(vm.ctx.types.frozendict_type)
+            }) {
+                Some(dict) => {
                     for (key, val) in dict {
-                        // FIXME: ints are key-compatible
-                        if let Some(num) = key.downcast_ref::<PyInt>() {
-                            new_dict.set_item(
-                                &*num.as_bigint().to_i32().to_pyobject(vm),
-                                val,
-                                vm,
-                            )?;
+                        if key.downcast_ref::<PyInt>().is_some() {
+                            new_dict.set_item(&*key, val, vm)?;
                         } else if let Some(string) = key.downcast_ref::<PyStr>() {
                             if string.len() == 1 {
                                 let num_value =
@@ -1609,7 +1608,7 @@ impl Py<PyStr> {
                     }
                     Ok(new_dict.to_pyobject(vm))
                 }
-                _ => Err(vm.new_value_error(
+                _ => Err(vm.new_type_error(
                     "if you give only one argument to maketrans it must be a dict",
                 )),
             }

diff --git a/crates/vm/src/stdlib/_collections/ordered_dict.rs b/crates/vm/src/stdlib/_collections/ordered_dict.rs
@@ -138,7 +138,7 @@ pub(crate) mod ordered_dict {
         traverse = "manual"
     )]
     #[derive(Debug)]
-    struct PyOrderedDict {
+    pub(crate) struct PyOrderedDict {
         dict: PyDict,
         links: PyMutex<ODictLinks>,
     }

diff --git a/crates/vm/src/stdlib/mod.rs b/crates/vm/src/stdlib/mod.rs
@@ -3,7 +3,7 @@ mod _abc;
 pub(crate) mod _ast;
 mod _codecs;
 mod _collections;
-pub(crate) use _collections::ordered_dict::ordered_dict::PyOrderedDictItems;
+pub(crate) use _collections::ordered_dict::ordered_dict::{PyOrderedDict, PyOrderedDictItems};
 mod _functools;
 mod _imp;
 pub mod _io;