Cache array-child + wall topology by IFC generation

Two hot paths the gizmo polls fire every viewport event memoise
their result against tool.Parametric.get_geom_generation():

- tool.Blender.Modifier.any_selected_array_child caches the
  per-selection scan against the selection identity-set + the
  IFC generation token so a stable selection during a drag
  doesn't re-walk every selected object's BBIM_Array pset every
  frame.
- bim/module/model/wall.py grows a pair-predicate + connection
  cache that the wall topology gizmos hit; both keyed on
  (pair_uids, predicate_kind, generation) so a wall split or
  axis edit invalidates correctly via the generation bump.

Behavioural contract is unchanged — stale entries are evicted
on generation bump; cache miss returns the same value the
un-cached path returned.

Generated with the assistance of an AI coding tool.

src/bonsai/test/tool/test_blender_any_array_child_cache.py

@@ -0,0 +1,152 @@
+# Bonsai - OpenBIM Blender Add-on
+# Copyright (C) 2026
+#
+# This file is part of Bonsai.
+#
+# Bonsai is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Bonsai is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
+#
+# This file was generated with the assistance of an AI coding tool.
+
+"""Cache-invalidation tests for ``tool.Blender.Modifier.any_selected_is_array_child``.
+
+The wall-topology gizmo gate calls this on every viewport input event. The
+underlying ``is_array_child`` check is a BBIM_Array pset lookup per selected
+object; without memoisation that runs N_selected times per event. These
+tests pin that the cache reuses results across identical (selection, IFC
+generation) pairs and invalidates on either change."""
+
+from unittest.mock import Mock, patch
+
+import pytest
+
+pytestmark = pytest.mark.model
+
+
+@pytest.fixture(autouse=True)
+def _reset_memo():
+    from bonsai import tool
+
+    saved = getattr(tool.Blender.Modifier, "_any_selected_array_child_memo", None)
+    tool.Blender.Modifier._any_selected_array_child_memo = None
+    yield
+    tool.Blender.Modifier._any_selected_array_child_memo = saved
+
+
+def _mock_obj(name: str) -> Mock:
+    obj = Mock()
+    obj.name = name
+    return obj
+
+
+def test_repeat_call_within_generation_reuses_cache():
+    from bonsai import tool
+
+    obj_a = _mock_obj("Wall.001")
+    obj_b = _mock_obj("Wall.002")
+
+    is_array_child_calls = {"n": 0}
+
+    def counting_is_array_child(elem):
+        is_array_child_calls["n"] += 1
+        return False
+
+    with patch("bonsai.tool.blender.tool.Blender.get_selected_objects", return_value=[obj_a, obj_b]), patch(
+        "bonsai.tool.blender.tool.Parametric.get_geom_generation", return_value=5
+    ), patch("bonsai.tool.blender.tool.Ifc.get_entity", return_value=Mock()), patch.object(
+        tool.Blender.Modifier, "is_array_child", side_effect=counting_is_array_child
+    ):
+        first = tool.Blender.Modifier.any_selected_is_array_child()
+        second = tool.Blender.Modifier.any_selected_is_array_child()
+
+    assert first is False
+    assert second is False
+    assert is_array_child_calls["n"] == 2, "First call walks N_selected; second call must reuse cached result"
+
+
+def test_generation_advance_invalidates_cache():
+    from bonsai import tool
+
+    obj = _mock_obj("Wall.001")
+    gen_state = {"gen": 1}
+
+    call_count = {"n": 0}
+
+    def counting_is_array_child(elem):
+        call_count["n"] += 1
+        return False
+
+    with patch("bonsai.tool.blender.tool.Blender.get_selected_objects", return_value=[obj]), patch(
+        "bonsai.tool.blender.tool.Parametric.get_geom_generation", side_effect=lambda: gen_state["gen"]
+    ), patch("bonsai.tool.blender.tool.Ifc.get_entity", return_value=Mock()), patch.object(
+        tool.Blender.Modifier, "is_array_child", side_effect=counting_is_array_child
+    ):
+        tool.Blender.Modifier.any_selected_is_array_child()
+        first = call_count["n"]
+        gen_state["gen"] = 2
+        tool.Blender.Modifier.any_selected_is_array_child()
+
+    assert call_count["n"] > first
+
+
+def test_selection_change_invalidates_cache():
+    from bonsai import tool
+
+    obj_a = _mock_obj("Wall.001")
+    obj_b = _mock_obj("Wall.002")
+    selection = {"sel": [obj_a]}
+
+    call_count = {"n": 0}
+
+    def counting_is_array_child(elem):
+        call_count["n"] += 1
+        return False
+
+    with patch("bonsai.tool.blender.tool.Blender.get_selected_objects", side_effect=lambda: selection["sel"]), patch(
+        "bonsai.tool.blender.tool.Parametric.get_geom_generation", return_value=1
+    ), patch("bonsai.tool.blender.tool.Ifc.get_entity", return_value=Mock()), patch.object(
+        tool.Blender.Modifier, "is_array_child", side_effect=counting_is_array_child
+    ):
+        tool.Blender.Modifier.any_selected_is_array_child()
+        first = call_count["n"]
+        selection["sel"] = [obj_a, obj_b]
+        tool.Blender.Modifier.any_selected_is_array_child()
+
+    assert call_count["n"] > first
+
+
+def test_short_circuits_on_first_hit():
+    """``is_array_child`` returning True for the first selected object must
+    short-circuit; the rest of the selection isn't walked. Belt-and-suspenders
+    test — the early-return existed before the cache wrap and must survive it."""
+    from bonsai import tool
+
+    obj_a = _mock_obj("Wall.001")
+    obj_b = _mock_obj("Wall.002")
+    obj_c = _mock_obj("Wall.003")
+
+    call_count = {"n": 0}
+
+    def counting_is_array_child(elem):
+        call_count["n"] += 1
+        return True
+
+    with patch("bonsai.tool.blender.tool.Blender.get_selected_objects", return_value=[obj_a, obj_b, obj_c]), patch(
+        "bonsai.tool.blender.tool.Parametric.get_geom_generation", return_value=1
+    ), patch("bonsai.tool.blender.tool.Ifc.get_entity", return_value=Mock()), patch.object(
+        tool.Blender.Modifier, "is_array_child", side_effect=counting_is_array_child
+    ):
+        result = tool.Blender.Modifier.any_selected_is_array_child()
+
+    assert result is True
+    assert call_count["n"] == 1