Return None for missing Optional field attribute access

.github/workflows/hygiene.yaml

@@ -11,7 +11,7 @@ on:
 jobs:
   hygiene:
     runs-on: ubuntu-latest
-    name: Ruff
+    name: ruff and basedpyright
     steps:
     - uses: actions/checkout@v3
     - name: setup-python

src/implicitdict/__init__.py

@@ -160,10 +160,13 @@ def __getattribute__(self, item):
             self_type_name = _fullname(self_type)
             if self_type_name in fields_info_by_type:
                 if item in fields_info_by_type[self_type_name].all_fields:
-                    try:
-                        return self[item]
-                    except KeyError:
-                        raise AttributeError
+                    if item in fields_info_by_type[self_type_name].optional_fields:
+                        return self[item] if item in self else None
+                    else:
+                        try:
+                            return self[item]
+                        except KeyError:
+                            raise AttributeError
         return super().__getattribute__(item)
 
     def __setattr__(self, key, value):

tests/test_docpattern.py

@@ -8,10 +8,16 @@ class ResponseType(ImplicitDict):
     pass
 
 
+class QueryResponse(ImplicitDict):
+    json: dict
+
+
 class Query(ImplicitDict):
     participant_id: str | None
     """If specified, identifier of the USS/participant hosting the server involved in this query."""
 
+    response: QueryResponse
+
     def parse_json_result(self, parse_type: type[ResponseType]) -> ResponseType:
         """Parses the JSON result into the specified type.
 

tests/test_normal_usage.py

@@ -24,8 +24,8 @@ def test_basic_usage():
 
     # Optional fields that aren't specified simply don't exist
     assert "baz" not in data
-    with pytest.raises(AttributeError):
-        assert data.baz == 0
+    # ...but they default to None when the attribute is accessed
+    assert data.baz is None
 
     # Optional fields can be omitted (fields with defaults are optional)
     data = NormalUsageData(foo="asdf")

tests/test_optional.py

@@ -1,7 +1,5 @@
 import json
 
-import pytest
-
 from implicitdict import ImplicitDict
 
 from .test_types import OptionalData
@@ -43,11 +41,12 @@ def test_minimally_defined():
     assert "field_with_default" in data
     assert "optional_field2_with_none_default" in data
     assert "optional_field3_with_default" in data
-    with pytest.raises(AttributeError):
-        # Trying to reference the Optional field will result in a AttributeError
-        # To determine whether an Optional field is present, the user must check
-        # whether `"<FIELD_NAME>" in <OBJECT>` (see above).
-        assert data.optional_field1 is None
+
+    # Referencing the Optional field will return None.
+    # To differentiate between an actual value of None and the field being absent,
+    # the user must check whether `"<FIELD_NAME>" in <OBJECT>` (see above).
+    assert data.optional_field1 is None
+
     s = json.dumps(data)
     assert "required_field" in s
     assert "optional_field1" not in s
@@ -62,7 +61,10 @@ def test_getattr():
 
     data = OptionalData.example_values()["minimally_defined"]
     assert "optional_field1" not in data
-    assert getattr(data, "optional_field1", "getattrdefault") == "getattrdefault"
+
+    # To differentiate between an actual value of None and the field being absent,
+    # the user must check whether `"<FIELD_NAME>" in <OBJECT>` (see above).
+    assert getattr(data, "optional_field1", "getattrdefault") is None
 
 
 def test_provide_optional_field():