Preserve order for collections.OrderedDict (#1801)

Author: CloseChoice

src/input/input_python.rs

@@ -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))

tests/validators/test_dict.py

@@ -1,4 +1,5 @@
 import re
+import sys
 from collections import OrderedDict
 from collections.abc import Mapping
 from typing import Any
@@ -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(
+    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}