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Merged
merged 26 commits into from
Oct 6, 2025
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Merged

Preserve order for collections.OrderedDict #1801

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5980e5b
fix working
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fix strict and updates as request in PR
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6 changes: 4 additions & 2 deletions src/input/input_python.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -395,15 +395,17 @@ impl<'py> Input<'py> for Bound<'py, PyAny> {
Self: 'a;

fn strict_dict<'a>(&'a self) -> ValResult<GenericPyMapping<'a, 'py>> {
if let Ok(dict) = self.downcast::<PyDict>() {
if let Ok(dict) = self.downcast_exact::<PyDict>() {
Ok(GenericPyMapping::Dict(dict))
} else if self.is_instance_of::<PyDict>() {
Ok(GenericPyMapping::Mapping(self.downcast::<PyMapping>()?))
} else {
Err(ValError::new(ErrorTypeDefaults::DictType, self))
}
}

fn lax_dict<'a>(&'a self) -> ValResult<GenericPyMapping<'a, 'py>> {
if let Ok(dict) = self.downcast::<PyDict>() {
if let Ok(dict) = self.downcast_exact::<PyDict>() {
Ok(GenericPyMapping::Dict(dict))
} else if let Ok(mapping) = self.downcast::<PyMapping>() {
Ok(GenericPyMapping::Mapping(mapping))
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27 changes: 27 additions & 0 deletions tests/validators/test_dict.py
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Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
import re
import sys
from collections import OrderedDict
from collections.abc import Mapping
from typing import Any
Expand Down Expand Up @@ -313,3 +314,29 @@ def test_dict_fail_fast(fail_fast, expected):
v.validate_python({'a': 'b', 'c': 'd'})

assert exc_info.value.errors(include_url=False) == expected


@pytest.mark.skipif(
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note that we skip here due to the bug reported here: #1801 (comment)

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Hmm interesting, does GraalPy show the bug in a pure Python repro? Otherwise this might imply a PyO3 bug on GraalPy (or a GraalPy C API issue).

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havent managed to recreate this in pure python. So true, this might be a bug in pyo3, but as I understand it, pyo3 is calling the c api mapping code and this is where it goes wrong, therefore I assumed this is ok graalpy's c api, the mapping protocol is not directly exposed in python, so it makes sense that this cannot be reproduced there.

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@CloseChoice CloseChoice Oct 4, 2025 •
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So I managed to verify that this is a graalpy bug. Here is the code for the C extension:
dict_printer.c:

#include <Python.h>

static PyObject* print_dict(PyObject* self, PyObject* args) {
    PyObject* dict;

    if (!PyArg_ParseTuple(args, "O", &dict)) {
        return NULL;
    }

    PyObject* mapping = PyObject_GetIter(PyMapping_Items(dict));
    if (mapping == NULL) {
        PyErr_SetString(PyExc_TypeError, "Object is not a valid mapping");
        return NULL;
    }

    PyObject* item;
    printf("Mapping contents:\n");
    while ((item = PyIter_Next(mapping)) != NULL) {
        PyObject* key = PyTuple_GetItem(item, 0);
        PyObject* value = PyTuple_GetItem(item, 1);

        PyObject* key_str = PyObject_Str(key);
        PyObject* value_str = PyObject_Str(value);

        const char* key_cstr = PyUnicode_AsUTF8(key_str);
        const char* value_cstr = PyUnicode_AsUTF8(value_str);

        printf("  %s: %s\n", key_cstr, value_cstr);

        Py_DECREF(key_str);
        Py_DECREF(value_str);
        Py_DECREF(item);
    }

    Py_DECREF(mapping);

    if (PyErr_Occurred()) {
        return NULL;
    }

    Py_RETURN_NONE;
}

static PyMethodDef DictPrinterMethods[] = {
    {"print_dict", print_dict, METH_VARARGS, "Print all elements of a dictionary/mapping"},
    {NULL, NULL, 0, NULL}
};

static struct PyModuleDef dictprintermodule = {
    PyModuleDef_HEAD_INIT,
    "dict_printer",
    "A module to print dictionary/mapping elements",
    -1,
    DictPrinterMethods
};

PyMODINIT_FUNC PyInit_dict_printer(void) {
    return PyModule_Create(&dictprintermodule);
}

setup.py

from setuptools import setup, Extension

module = Extension('dict_printer',
                   sources=['dict_printer.c'])

setup(name='dict_printer',
      version='1.0',
      description='C extension to print dictionary/mapping elements',
      ext_modules=[module])

Then run python setup.py build_ext --inplace and execute

from collections import OrderedDict
import dict_printer

my_dict = OrderedDict({'a': 1, 'b': 2, 'c': 3})
my_dict.move_to_end('a')
dict_printer.print_dict(my_dict)
print(my_dict)

This outputs with graalpy:

Mapping contents:
  a: 1
  b: 2
  c: 3
OrderedDict({'b': 2, 'c': 3, 'a': 1})

using CPython:

Mapping contents:
  b: 2
  c: 3
  a: 1
OrderedDict([('b', 2), ('c', 3), ('a', 1)])

So, no worries, no extra work on pyo3 @davidhewitt. I'll check graalpy issues and file one if necessary and link the it in the test-skip string.

EDIT: Here is the graalpy issue I just opened: oracle/graalpython#553

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Super, thank you for going to such detail to verify this!

sys.implementation.name == 'graalpy',
reason='GraalPy has a bug where PyMapping.items() does not preserve OrderedDict order. See: https://github.com/oracle/graalpython/issues/553',
)
@pytest.mark.parametrize('strict', [True, False])
def test_ordered_dict_key_order_preservation(strict):
# GH 12273
v = SchemaValidator(cs.dict_schema(keys_schema=cs.str_schema(), values_schema=cs.int_schema()))

# Original issue
foo = OrderedDict({'a': 1, 'b': 2})
foo.move_to_end('a')

result = v.validate_python(foo, strict=strict)
assert list(result.keys()) == list(foo.keys()) == ['b', 'a']
assert result == {'b': 2, 'a': 1}

# More complex case
foo2 = OrderedDict({'x': 1, 'y': 2, 'z': 3})
foo2.move_to_end('x')

result2 = v.validate_python(foo2, strict=strict)
assert list(result2.keys()) == list(foo2.keys()) == ['y', 'z', 'x']
assert result2 == {'y': 2, 'z': 3, 'x': 1}
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