fix(rules): cones require line of effect from their origin (SRD aiming-a-spell.md: a cone 'affects only an area, creature, or object to which it has line of effect from its origin') - cone_cells drops geometrically-inside cells without corner-to-corner LoE from the caster square; line/cone barrier-cell semantics aligned (both templates include the barrier square the effect strikes, exclude everything behind it)

tests/test_area_shapes.py

@@ -18,7 +18,7 @@ from typing import TYPE_CHECKING
 
 import pytest
 
-from pf1e_simulator.areas import line_cells
+from pf1e_simulator.areas import cone_cells, line_cells
 from pf1e_simulator.combat import Action, CombatantState, CombatEngine
 from pf1e_simulator.dice import parse_dice
 from pf1e_simulator.grid import Grid
@@ -185,6 +185,48 @@ def test_cone_covers_the_full_90_degree_arc() -> None:
     assert foe_outside.hp == 100
 
 
+def test_cone_cells_require_line_of_effect_from_the_origin() -> None:
+    """Given: a wall column at col 4 (rows 4-8) between origin (6,2) and the
+    cell (6,5) that sits on the cone axis at distance 3
+    When: cone_cells builds a 3-cell east cone
+    Then: (6,5) is dropped - geometrically inside but without line of effect
+    from the origin (CRB, Line of Effect: a cone "affects only an area,
+    creature, or object to which it has line of effect from its origin");
+    on the same geometry without walls it stays in the template."""
+    walls = frozenset({(4, 4), (5, 4), (6, 4), (7, 4), (8, 4)})
+    grid = _walled_grid(walls)
+    cells = cone_cells(grid, (6, 2), (6, 3), 3)
+    assert (6, 3) in cells
+    assert (6, 4) in cells  # the cone reaches the barrier square itself
+    assert (6, 5) not in cells
+    open_cells = cone_cells(_open_grid(), (6, 2), (6, 3), 3)
+    assert (6, 5) in open_cells  # control: nothing else filters it out
+
+
+def test_cone_behind_a_solid_wall_does_not_hit_sheltered_creatures() -> None:
+    """Given: caster (6,2) aiming the 15-ft cone east at foe_front (6,3); a
+    wall column at col 4 (rows 4-8); foe_behind (6,5) sits on the cone axis
+    behind that wall
+    When: the cone resolves
+    Then: only foe_front is caught (one 1d6 consumed after the adjacent
+    foe_front's scripted -4 AoO d20 misses); foe_behind is untouched - the
+    cone stops at the solid barrier, it does not pass through it."""
+    caster = _caster()
+    walls = frozenset({(4, 4), (5, 4), (6, 4), (7, 4), (8, 4)})
+    foe_front = make_state(make_combatant("foe_front", hp=100), "monsters", (6, 3))
+    foe_behind = make_state(make_combatant("foe_behind", hp=100), "monsters", (6, 5))
+    eng = CombatEngine(
+        ScriptedRng([4, 4]), _walled_grid(walls), [caster, foe_front, foe_behind],
+        spell_registry=_REGISTRY,
+    )
+    result = eng._execute(
+        caster, Action(kind="cast_spell", target_id="foe_front", spell_name="Cone Sparks")
+    )
+    assert result.ok
+    assert foe_front.hp == 100 - 4
+    assert foe_behind.hp == 100
+
+
 def test_cone_directed_by_target_pos_point_cast() -> None:
     """Given: the same scene, no target_id — the cone is aimed at an explicit
     cell (6,5) via target_pos (U7b point cast)
@@ -256,7 +298,7 @@ def test_line_cells_stop_at_a_line_of_effect_barrier() -> None:
     grid = _walled_grid(frozenset({(6, 6)}))
     cells = line_cells(grid, (6, 2), (6, 8), 10)
     assert (6, 5) in cells
-    assert (6, 6) not in cells
+    assert (6, 6) in cells  # the bolt strikes the barrier square itself
     assert (6, 7) not in cells
     assert (6, 8) not in cells