ENH: implement FrozenDict with frozendict (#310)

* DX: implement hash test for `FrozenDict` and `ReactionInfo`
* ENH: inherit `FrozenDict` from `frozendict`
* MAINT: install `frozendict` as direct dependency

Author: redeboer

docs/conf.py

@@ -18,7 +18,7 @@
 from _extend_docstrings import extend_docstrings  # noqa: PLC2701
 
 
-def pick_newtype_attrs(some_type: type) -> list:
+def __get_newtypes(some_type: type) -> list:
     return [
         attr
         for attr in dir(some_type)
@@ -278,25 +278,20 @@ def pick_newtype_attrs(some_type: type) -> list:
 nb_execution_show_tb = True
 nb_execution_timeout = -1
 nb_output_stderr = "remove"
-
-
-nitpick_temp_names = [
-    *pick_newtype_attrs(EdgeQuantumNumbers),
-    *pick_newtype_attrs(NodeQuantumNumbers),
-]
-nitpick_temp_patterns = [
-    (r"py:(class|obj)", r"qrules\.quantum_numbers\." + name)
-    for name in nitpick_temp_names
-]
 nitpick_ignore_regex = [
     (r"py:(class|obj)", "json.encoder.JSONEncoder"),
+    (r"py:(class|obj)", r"frozendict(\.frozendict)?"),
     (r"py:(class|obj)", r"qrules\.topology\.EdgeType"),
     (r"py:(class|obj)", r"qrules\.topology\.KT"),
     (r"py:(class|obj)", r"qrules\.topology\.NewEdgeType"),
     (r"py:(class|obj)", r"qrules\.topology\.NewNodeType"),
     (r"py:(class|obj)", r"qrules\.topology\.NodeType"),
     (r"py:(class|obj)", r"qrules\.topology\.VT"),
-    *nitpick_temp_patterns,
+    *[
+        (r"py:(class|obj)", r"qrules\.quantum_numbers\." + name)
+        for name in __get_newtypes(EdgeQuantumNumbers)
+        + __get_newtypes(NodeQuantumNumbers)
+    ],
 ]
 nitpicky = True
 primary_domain = "py"

pyproject.toml

@@ -27,6 +27,7 @@ classifiers = [
 dependencies = [
     "PyYAML",
     "attrs >=20.1.0", # on_setattr and https://www.attrs.org/en/stable/api.html#next-gen
+    "frozendict",
     "jsonschema",
     "particle",
     "python-constraint",

src/qrules/topology.py

@@ -27,19 +27,12 @@
 import attrs
 from attrs import define, field, frozen
 from attrs.validators import deep_iterable, deep_mapping, instance_of
+from frozendict import frozendict
 
 from qrules._implementers import implement_pretty_repr
 
 if TYPE_CHECKING:
-    from collections.abc import (
-        ItemsView,
-        Iterable,
-        Iterator,
-        KeysView,
-        Mapping,
-        Sequence,
-        ValuesView,
-    )
+    from collections.abc import Iterable, Mapping, Sequence
 
     from IPython.lib.pretty import PrettyPrinter
 
@@ -56,31 +49,8 @@ def __lt__(self, other: Any) -> bool: ...
 
 
 @total_ordering
-class FrozenDict(abc.Hashable, abc.Mapping, Generic[KT, VT]):
-    """An **immutable** and **hashable** version of a `dict`.
-
-    `FrozenDict` makes it possible to make classes hashable if they are decorated with
-    :func:`attr.frozen` and contain `~typing.Mapping`-like attributes. If these
-    attributes were to be implemented with a normal `dict`, the instance is strictly
-    speaking still mutable (even if those attributes are a `property`) and the class is
-    therefore not safely hashable.
-
-    .. warning:: The keys have to be comparable, that is, they need to have a
-        :meth:`~object.__lt__` method.
-    """
-
-    def __init__(self, mapping: Mapping | None = None) -> None:
-        self.__mapping: dict[KT, VT] = {}
-        if mapping is not None:
-            self.__mapping = dict(mapping)
-        self.__hash = hash(None)
-        if len(self.__mapping) != 0:
-            self.__hash = 0
-            for key_value_pair in self.items():
-                self.__hash ^= hash(key_value_pair)
-
-    def __repr__(self) -> str:
-        return f"{type(self).__name__}({self.__mapping})"
+class FrozenDict(frozendict, Generic[KT, VT]):
+    """A sortable version of :code:`frozendict`."""
 
     def _repr_pretty_(self, p: PrettyPrinter, cycle: bool) -> None:
         class_name = type(self).__name__
@@ -96,15 +66,6 @@ def _repr_pretty_(self, p: PrettyPrinter, cycle: bool) -> None:
             p.breakable()
             p.text("})")
 
-    def __iter__(self) -> Iterator[KT]:
-        return iter(self.__mapping)
-
-    def __len__(self) -> int:
-        return len(self.__mapping)
-
-    def __getitem__(self, key: KT) -> VT:
-        return self.__mapping[key]
-
     def __gt__(self, other: Any) -> bool:
         if isinstance(other, abc.Mapping):
             sorted_self = _convert_mapping_to_sorted_tuple(self)
@@ -117,18 +78,6 @@ def __gt__(self, other: Any) -> bool:
         )
         raise NotImplementedError(msg)
 
-    def __hash__(self) -> int:
-        return self.__hash
-
-    def keys(self) -> KeysView[KT]:
-        return self.__mapping.keys()
-
-    def items(self) -> ItemsView[KT, VT]:
-        return self.__mapping.items()
-
-    def values(self) -> ValuesView[VT]:
-        return self.__mapping.values()
-
 
 def _convert_mapping_to_sorted_tuple(
     mapping: Mapping[KT, VT],

tests/unit/test_topology.py

@@ -1,3 +1,5 @@
+import hashlib
+import pickle  # noqa: S403
 import typing
 
 import pytest
@@ -6,7 +8,7 @@
 
 from qrules.topology import (
     Edge,
-    FrozenDict,  # noqa: F401  # pyright: ignore[reportUnusedImport]
+    FrozenDict,  # pyright: ignore[reportUnusedImport]
     InteractionNode,
     MutableTopology,
     SimpleStateTransitionTopologyBuilder,
@@ -39,6 +41,23 @@ def test_immutability(self):
             edge.ending_node_id += 1
 
 
+class TestFrozenDict:
+    def test_hash(self):
+        obj: FrozenDict = FrozenDict({})
+        assert _compute_hash(obj) == "067705e70d037311d05daae1e32e1fce"
+
+        obj = FrozenDict({"key1": "value1"})
+        assert _compute_hash(obj) == "56b0520e2a3af550c0f488cd5de2d474"
+
+        obj = FrozenDict({
+            "key1": "value1",
+            "key2": 2,
+            "key3": (1, 2, 3),
+            "key4": FrozenDict({"nested_key": "nested_value"}),
+        })
+        assert _compute_hash(obj) == "8568f73c07fce099311f010061f070c6"
+
+
 class TestInteractionNode:
     def test_constructor_exceptions(self):
         with pytest.raises(TypeError):
@@ -188,6 +207,9 @@ def test_constructor_exceptions(self, nodes, edges):
         ):
             assert Topology(nodes, edges)
 
+    def test_hash(self, two_to_three_decay: Topology):
+        assert _compute_hash(two_to_three_decay) == "cbaea5d94038a3ad30888014a7b3ae20"
+
     @pytest.mark.parametrize("repr_method", [repr, pretty])
     def test_repr_and_eq(self, repr_method, two_to_three_decay: Topology):
         topology = eval(repr_method(two_to_three_decay))
@@ -299,3 +321,15 @@ def test_create_n_body_topology(n_initial: int, n_final: int, exception):
         assert len(topology.outgoing_edge_ids) == n_final
         assert len(topology.intermediate_edge_ids) == 0
         assert len(topology.nodes) == 1
+
+
+def _compute_hash(obj) -> str:
+    b = _to_bytes(obj)
+    h = hashlib.md5(b)  # noqa: S324
+    return h.hexdigest()
+
+
+def _to_bytes(obj) -> bytes:
+    if isinstance(obj, bytes | bytearray):
+        return obj
+    return pickle.dumps(obj)

tests/unit/test_transition.py

@@ -1,4 +1,6 @@
 # pyright: reportUnusedImport=false
+import hashlib
+import pickle  # noqa: S403
 from copy import deepcopy
 from fractions import Fraction
 
@@ -44,6 +46,13 @@ def test_repr(self, repr_method, reaction: ReactionInfo):
     def test_hash(self, reaction: ReactionInfo):
         assert hash(deepcopy(reaction)) == hash(reaction)
 
+    def test_hash_value(self, reaction: ReactionInfo):
+        expected_hash = {
+            "canonical-helicity": "65106a44301f9340e633d09f66ad7d17",
+            "helicity": "9646d3ee5c5e8534deb8019435161f2e",
+        }[reaction.formalism]
+        assert _compute_hash(reaction) == expected_hash
+
 
 class TestState:
     @pytest.mark.parametrize(
@@ -106,3 +115,15 @@ def test_regex_pattern(self):
             "Delta(1900)++",
             "Delta(1920)++",
         ]
+
+
+def _compute_hash(obj) -> str:
+    b = _to_bytes(obj)
+    h = hashlib.md5(b)  # noqa: S324
+    return h.hexdigest()
+
+
+def _to_bytes(obj) -> bytes:
+    if isinstance(obj, bytes | bytearray):
+        return obj
+    return pickle.dumps(obj)