fix(rules): a cone/line template excludes the caster's whole footprint, not just the anchor cell (SRD aiming-a-spell.md: 'It starts from any corner of your square' - every occupied square is origin space and never inside its own area) - cone_cells/line_cells take caster_cells; combat passes caster.occupied_cells(); 1x1 casters bit-identical; documented simplification: a grazed caster cell still consumes a length slot

tests/test_conformance_caster_footprint_origin.py

@@ -0,0 +1,74 @@
+"""A multi-cell caster's WHOLE footprint is outside its own cone/line.
+
+PF1e SRD "Aiming a Spell" (aiming-a-spell.md): a cone and a line "start from
+any corner of your square" -- for a creature with a space larger than one
+square, every occupied square is part of the origin space, so none of them is
+ever inside the creature's own area (the template "shoots away from you").
+The engine used to exclude only the anchor cell, so a Large caster's other
+cells fell inside its own cone/line template.
+"""
+
+from __future__ import annotations
+
+from pf1e_simulator.areas import cone_cells, line_cells
+from pf1e_simulator.combat import CombatEngine
+from pf1e_simulator.grid import Grid
+from pf1e_simulator.map import MapSpec, TerrainType
+from pf1e_simulator.rng import ScriptedRng
+from pf1e_simulator.spells import AreaEffect
+from tests.test_observation_enriched import make_combatant, make_state
+
+_FLOOR = TerrainType(type="floor", move_cost=1)
+
+
+def _open_grid() -> Grid:
+    return Grid.from_spec(
+        MapSpec(
+            name="footprint-origin",
+            terrain=tuple(["." * 8] * 8),
+            legend={".": _FLOOR},
+        )
+    )
+
+
+# A Large caster anchored at (1,1) occupies the 2x2 block below. Aiming east
+# from the anchor, the ray/cone grazes the caster's own cells (1,2) and (2,2).
+_FOOTPRINT = frozenset({(1, 1), (1, 2), (2, 1), (2, 2)})
+
+
+def test_cone_excludes_the_whole_caster_footprint() -> None:
+    grid = _open_grid()
+    cells = cone_cells(grid, (1, 1), (1, 6), 4, caster_cells=_FOOTPRINT)
+    assert not cells & _FOOTPRINT
+    # The exclusion is the footprint only: the cone keeps everything past it.
+    assert (1, 3) in cells
+    assert (2, 3) in cells
+
+
+def test_line_excludes_the_whole_caster_footprint() -> None:
+    grid = _open_grid()
+    cells = line_cells(grid, (1, 1), (1, 6), 6, caster_cells=_FOOTPRINT)
+    assert (1, 2) not in cells
+    assert (1, 3) in cells
+    assert (1, 7) in cells
+
+
+def test_single_cell_caster_templates_are_unchanged() -> None:
+    """1x1 regression: the footprint is just the anchor, which the old code
+    already dropped -- both templates must be identical to the pre-fix set."""
+    grid = _open_grid()
+    old_cone = cone_cells(grid, (1, 1), (1, 6), 4)
+    new_cone = cone_cells(grid, (1, 1), (1, 6), 4, caster_cells=frozenset({(1, 1)}))
+    assert old_cone == new_cone
+    old_line = line_cells(grid, (1, 1), (1, 6), 6)
+    new_line = line_cells(grid, (1, 1), (1, 6), 6, caster_cells=frozenset({(1, 1)}))
+    assert old_line == new_line
+
+
+def test_large_caster_is_not_caught_by_its_own_cone() -> None:
+    caster_spec = make_combatant("ogre", size="Large", hp=20)
+    caster = make_state(caster_spec, "players", (1, 1))
+    engine = CombatEngine(ScriptedRng([]), _open_grid(), [caster])
+    effect = AreaEffect(shape="cone", radius_ft=30)
+    affected = engine._area_creatures(effect, caster, (1, 6))
+    assert affected == []