Make get_first nullable

Author: lucc

khard/contacts.py

@@ -112,12 +112,19 @@ def __init__(self, vcard: vobject.base.Component,
     def __str__(self) -> str:
         return self.formatted_name
 
-    def get_first(self, property: str, default: str = "") -> str:
+    @overload
+    def get_first(self, property: Literal["n"]) -> Optional[vobject.vcard.Name]: ...
+    @overload
+    def get_first(self, property: Literal["adr"]) -> Optional[vobject.vcard.Address]: ...
+    @overload
+    def get_first(self, property: str) -> Optional[str]: ...
+    def get_first(self, property: str) -> Union[None, str, vobject.vcard.Name,
+                                                vobject.vcard.Address]:
         """Get a property from the underlying vCard.
 
         This method should only be called for properties with cardinality \\*1
         (zero or one).  Otherwise only the first value will be returned. If the
-        property is not present a default will be returned.
+        property is not present None will be retuned.
 
         The type annotation for the return value is str but this is not
         enforced so it is up to the caller to make sure to only call this
@@ -132,7 +139,7 @@ def get_first(self, property: str, default: str = "") -> str:
         try:
             return getattr(self.vcard, property).value
         except AttributeError:
-            return default
+            return None
 
     def _get_multi_property(self, name: str) -> list:
         """Get a vCard property that can exist more than once.
@@ -259,7 +266,7 @@ def _get_types_for_vcard_object(self, object: vobject.base.ContentLine,
         return [default_type]
 
     @property
-    def version(self) -> str:
+    def version(self) -> Optional[str]:
         return self.get_first("version")
 
     @version.setter
@@ -274,7 +281,7 @@ def version(self, value: str) -> None:
         version.value = convert_to_vcard("version", value, ObjectType.str)
 
     @property
-    def uid(self) -> str:
+    def uid(self) -> Optional[str]:
         return self.get_first("uid")
 
     @uid.setter
@@ -470,7 +477,7 @@ def _prepare_birthday_value(self, date: Date) -> tuple[Optional[str],
 
     @property
     def kind(self) -> str:
-        return self.get_first(self._kind_attribute_name().lower(), self._default_kind)
+        return self.get_first(self._kind_attribute_name().lower()) or self._default_kind
 
     @kind.setter
     def kind(self, value: str) -> None:
@@ -487,10 +494,15 @@ def _kind_attribute_name(self) -> str:
 
     @property
     def formatted_name(self) -> str:
-        return self.get_first("fn")
+        fn = self.get_first("fn")
+        if fn:
+            return fn
+        self.formatted_name = ""
+        return self.get_first("fn") or ""
 
     @formatted_name.setter
     def formatted_name(self, value: str) -> None:
+        # TODO cardinality 1*
         """Set the FN field to the new value.
 
         All previously existing FN fields are deleted.  Version 4 of the specs
@@ -1303,9 +1315,11 @@ def to_yaml(self) -> str:
             "Note": self.notes,
             "Webpage": self.webpages,
             "Anniversary":
-                helpers.yaml_anniversary(self.anniversary, self.version),
+                helpers.yaml_anniversary(self.anniversary, self.version or
+                                         self._default_version),
             "Birthday":
-                helpers.yaml_anniversary(self.birthday, self.version),
+                helpers.yaml_anniversary(self.birthday, self.version or
+                                         self._default_version),
             "Address": helpers.yaml_addresses(
                 self.post_addresses, ["Box", "Extended", "Street", "Code",
                     "City", "Region", "Country"], defaults=["home"])

khard/khard.py

@@ -210,9 +210,9 @@ def list_contacts(vcard_list: list[Contact], fields: Iterable[str] = (),
                 row.append(formatter.get_special_field(vcard, field))
             elif field == 'uid':
                 if parsable:
-                    row.append(vcard.uid)
-                elif abook_collection.get_short_uid(vcard.uid):
-                    row.append(abook_collection.get_short_uid(vcard.uid))
+                    row.append(vcard.uid or "")
+                elif uid := abook_collection.get_short_uid(vcard.uid or ""):
+                    row.append(uid)
                 else:
                     row.append("")
             else:

test/test_query.py

@@ -105,11 +105,7 @@ def test_and_queries_match_after_sorting(self):
 
 
 class TestFieldQuery(unittest.TestCase):
-    @unittest.expectedFailure
     def test_empty_field_values_match_if_the_field_is_present(self):
-        # This test currently fails because the Contact class has all
-        # attributes set because they are properties.  So the test in the query
-        # class if an attribute is present never fails.
         uid = "Some Test Uid"
         vcard1 = TestContact(uid=uid)
         vcard2 = TestContact()

test/test_vcard_wrapper.py

@@ -564,8 +564,7 @@ def test_get_only_the_first_property(self):
 
     def test_returns_the_default(self):
         wrapper = TestVCardWrapper()
-        self.assertEqual(wrapper.get_first("title"), "")
-        self.assertEqual(wrapper.get_first("title", "foo"), "foo")
+        self.assertIsNone(wrapper.get_first("title"))
 
     def test_can_return_any_value_contradicting_type_annotation(self):
         """This is discouraged!"""