Deprecate betty.functools.walk()

betty/extension/cotton_candy/__init__.py

@@ -22,7 +22,6 @@
 from betty.config import Configuration
 from betty.extension.cotton_candy.search import Index
 from betty.extension.npm import _Npm, _NpmBuilder, npm
-from betty.functools import walk
 from betty.generate import Generator, GenerationContext
 from betty.gui import GuiBuilder
 from betty.jinja2 import (
@@ -438,9 +437,9 @@ def _person_timeline_events(person: Person, lifetime_threshold: int) -> Iterable
             is_public,
             (
                 # All ancestors.
-                *walk(person, "parents"),
+                *person.ancestors,
                 # All descendants.
-                *walk(person, "children"),
+                *person.descendants,
                 # All siblings.
                 *person.siblings,
             ),

betty/functools.py

@@ -20,10 +20,15 @@
     Awaitable,
 )
 
+from betty.warnings import deprecated
+
 T = TypeVar("T")
 U = TypeVar("U")
 
 
+@deprecated(
+    "This function is deprecated as of Betty 0.3.4, and will be removed in Betty 0.4.x. Instead, use a custom function, tailored to your data type."
+)
 def walk(item: Any, attribute_name: str) -> Iterable[Any]:
     """
     Walk over a graph of objects by following a single attribute.

betty/model/ancestry.py

@@ -4,7 +4,7 @@
 
 from __future__ import annotations
 
-from collections.abc import MutableSequence
+from collections.abc import MutableSequence, Iterator
 from contextlib import suppress
 from enum import Enum
 from pathlib import Path
@@ -1851,6 +1851,12 @@ def entity_type_label(cls) -> Str:
     def entity_type_label_plural(cls) -> Str:
         return Str._("People")
 
+    @property
+    def ancestors(self) -> Iterator[Person]:
+        for parent in self.parents:
+            yield parent
+            yield from parent.ancestors
+
     @property
     def siblings(self) -> list[Person]:
         siblings = []
@@ -1860,6 +1866,12 @@ def siblings(self) -> list[Person]:
                     siblings.append(sibling)
         return siblings
 
+    @property
+    def descendants(self) -> Iterator[Person]:
+        for child in self.children:
+            yield child
+            yield from child.descendants
+
     @property
     def associated_files(self) -> Iterable[File]:
         files = [

betty/privatizer.py

@@ -9,7 +9,6 @@
 from datetime import datetime
 from typing import Iterator, TypeAlias, Any
 
-from betty.functools import walk
 from betty.locale import DateRange, Date, Localizer
 from betty.model import Entity
 from betty.model.ancestry import (
@@ -199,7 +198,7 @@ def _determine_person_privacy(self, person: Person) -> None:
                 return
 
         # If any descendant has any expired event, the person is considered not private.
-        for descendant in walk(person, "children"):
+        for descendant in person.descendants:
             if self.has_expired(descendant, 1):
                 person.public = True
                 return

betty/tests/test_functools.py

@@ -1,14 +1,15 @@
 from collections.abc import Awaitable, Callable, Iterable
-from typing import Any
+from typing import Any, Self
 
 import pytest
 
 from betty.functools import walk, slice_to_range, Do
+from betty.warnings import BettyDeprecationWarning
 
 
 class TestWalk:
     class _Item:
-        def __init__(self, child: "TestWalk._Item | Iterable[TestWalk._Item] | None"):
+        def __init__(self, child: Self | Iterable[Self] | None):
             self.child = child
 
     @pytest.mark.parametrize(
@@ -21,44 +22,50 @@ def __init__(self, child: "TestWalk._Item | Iterable[TestWalk._Item] | None"):
         ],
     )
     async def test_with_invalid_attribute(self, item: Any) -> None:
-        with pytest.raises(AttributeError):
-            list(walk(item, "invalid_attribute_name"))
+        with pytest.warns(BettyDeprecationWarning):
+            with pytest.raises(AttributeError):
+                list(walk(item, "invalid_attribute_name"))
 
     async def test_one_to_one_without_descendants(self) -> None:
-        item = self._Item(None)
-        actual = walk(item, "child")
-        expected: list[None] = []
-        assert expected == list(actual)
+        with pytest.warns(BettyDeprecationWarning):
+            item = self._Item(None)
+            actual = walk(item, "child")
+            expected: list[None] = []
+            assert expected == list(actual)
 
     async def test_one_to_one_with_descendants(self) -> None:
-        grandchild = self._Item(None)
-        child = self._Item(grandchild)
-        item = self._Item(child)
-        actual = walk(item, "child")
-        expected = [child, grandchild]
-        assert expected == list(actual)
+        with pytest.warns(BettyDeprecationWarning):
+            grandchild = self._Item(None)
+            child = self._Item(grandchild)
+            item = self._Item(child)
+            actual = walk(item, "child")
+            expected = [child, grandchild]
+            assert expected == list(actual)
 
     async def test_one_to_many_without_descendants(self) -> None:
-        item = self._Item([])
-        actual = walk(item, "child")
-        expected: list[None] = []
-        assert expected == list(actual)
+        with pytest.warns(BettyDeprecationWarning):
+            item = self._Item([])
+            actual = walk(item, "child")
+            expected: list[None] = []
+            assert expected == list(actual)
 
     async def test_with_one_to_many_descendants(self) -> None:
-        grandchild = self._Item([])
-        child = self._Item([grandchild])
-        item = self._Item([child])
-        actual = walk(item, "child")
-        expected = [child, grandchild]
-        assert expected == list(actual)
+        with pytest.warns(BettyDeprecationWarning):
+            grandchild = self._Item([])
+            child = self._Item([grandchild])
+            item = self._Item([child])
+            actual = walk(item, "child")
+            expected = [child, grandchild]
+            assert expected == list(actual)
 
     async def test_with_mixed_descendants(self) -> None:
-        grandchild = self._Item([])
-        child = self._Item(grandchild)
-        item = self._Item([child])
-        actual = walk(item, "child")
-        expected = [child, grandchild]
-        assert expected == list(actual)
+        with pytest.warns(BettyDeprecationWarning):
+            grandchild = self._Item([])
+            child = self._Item(grandchild)
+            item = self._Item([child])
+            actual = walk(item, "child")
+            expected = [child, grandchild]
+            assert expected == list(actual)
 
 
 class TestSliceToRange: