Judge three more rules by a drained monster's Hit Dice, and give death spell its cube

CHANGELOG.md

@@ -32,12 +32,14 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 - A plain [`Rest`][osrlib.crawl.commands.Rest] in a dungeon now checks for wandering monsters at the level's full chance. Before, every rest took 1 off the chance, so a level with the usual 1 in 6 chance never rolled during a rest and resting was always safe. The session still adds 1 for noise and 1 for bright light, and a rest of a night or a day still checks once each turn and stops when monsters come. To rest quietly and take the 1 off, set the new `hidden` field. The `resting` keyword of [`wandering_check`][osrlib.crawl.exploration.wandering_check] still takes 1 off the chance. [`GameSession.advance_turns`][osrlib.crawl.session.GameSession.advance_turns] now sets it from `hidden`, so `advance_turns(resting=True)` alone no longer lowers the chance. It still counts the turns as rest.
 - An `attack` in a [`BattleDeclaration`][osrlib.crawl.commands.BattleDeclaration] with no `weapon_id` now uses the wielded weapon that suits the attack (#162). Before, the member struck unarmed, even with a sword in hand. The group's distance when the session accepts the round decides the attack: melee at 5 feet or less, missile beyond. The session takes the first wielded weapon, in the order the member equipped them, that can make that attack. For a missile attack it prefers the first whose long range reaches the group. A real weapon comes before an improvised one, like a torch, so a member who lit a torch and then drew a sword swings the sword. The torch still counts when the member wields nothing else that suits the attack. The session passes over a splash weapon, like a flask of oil, and an item with no weapon stats, like a wand. A member with no suitable weapon still strikes unarmed. The round plays out as if you had named the chosen weapon, and the command log records the declaration as you sent it. [`BattleDeclaration.weapon_id`][osrlib.crawl.commands.BattleDeclaration.weapon_id] describes the choice. A declaration that names a weapon works as before.
 - A wand, staff, or rod use and a turning declared in [`ResolveBattleRound`][osrlib.crawl.commands.ResolveBattleRound] are checked again in the magic phase, just before they resolve, as a spell cast and a scroll read are (#145). Before, they resolved even when the round had changed something they depend on. For example, a staff of striking struck a group that had already run out of melee reach. Now a declaration that fails the second check fizzles, and the session reports it with a [`DeclarationFizzledEvent`][osrlib.core.events.DeclarationFizzledEvent]. A device that fizzles was never used, so it keeps its charge, isn't identified, and doesn't break the user's invisibility. A turning that fizzles rolls nothing. A device use or turning that passes the second check resolves with the same rolls as before.
-- Some command logs recorded under 2.0.1 don't replay under this release. A log that contains a command this release refuses makes [`replay_game`][osrlib.persistence.replay_game] raise [`ContentValidationError`][osrlib.errors.ContentValidationError]. Two commands that 2.0.1 accepted are refused now, so a log that contains one of them raises: a potion `UseItem` aimed at another member, and a temple service that would do nothing. Other logs replay without an error but play out differently. That happens with *sleep* cast at a drained monster, a lair the party left and came back to, a rest in a dungeon, a rest that a wandering monster interrupted, a trap save with a `modifier`, or a chute trap where every member passed the save. In battle, it also happens with a monster that regenerates (a troll, a thoul, or a vampire), a monster whose attack has an effect (like a ghoul's paralysing claw or a wight's level drain), a basilisk's or a medusa's gaze, a melee attack on a petrified creature, a monster that can choose between attack routines (a spitting cobra, a thoul, a mule, a minotaur, a wererat, or a monster of your own with more than one unlabelled routine), an attack declared with no `weapon_id` by a member who wields a weapon, or a device use (a wand, staff, or rod) or a turning that now fizzles. Each of these changes has an entry in this section or under Fixed. Loading a 2.0.1 save with [`load_game`][osrlib.persistence.load_game] isn't affected, because a load restores the saved state and runs no commands. The loaded game then plays on under this release's rules.
+- Some command logs recorded under 2.0.1 don't replay under this release. A log that contains a command this release refuses makes [`replay_game`][osrlib.persistence.replay_game] raise [`ContentValidationError`][osrlib.errors.ContentValidationError]. Two commands that 2.0.1 accepted are refused now, so a log that contains one of them raises: a potion `UseItem` aimed at another member, and a temple service that would do nothing. Other logs replay without an error but play out differently. That happens with *sleep* cast at a drained monster, a *confusion* re-save, a protection scroll, or the 5 Hit Dice rule met with a drained monster, a *death spell* cast at a group, a lair the party left and came back to, a rest in a dungeon, a rest that a wandering monster interrupted, a trap save with a `modifier`, or a chute trap where every member passed the save. In battle, it also happens with a monster that regenerates (a troll, a thoul, or a vampire), a monster whose attack has an effect (like a ghoul's paralysing claw or a wight's level drain), a basilisk's or a medusa's gaze, a melee attack on a petrified creature, a monster that can choose between attack routines (a spitting cobra, a thoul, a mule, a minotaur, a wererat, or a monster of your own with more than one unlabelled routine), an attack declared with no `weapon_id` by a member who wields a weapon, or a device use (a wand, staff, or rod) or a turning that now fizzles. Each of these changes has an entry in this section or under Fixed. Loading a 2.0.1 save with [`load_game`][osrlib.persistence.load_game] isn't affected, because a load restores the saved state and runs no commands. The loaded game then plays on under this release's rules.
 
 ### Fixed
 
 - A ring of regeneration no longer heals fire or acid damage, as the ring's entry in the OSE SRD says. Before, the ring healed every kind of damage at 1 hit point a round. Now [`deal_damage`][osrlib.core.combat.deal_damage] records fire and acid damage to the wearer in the new field [`Character.nonregen_damage`][osrlib.core.character.Character.nonregen_damage], and the ring heals the wearer only up to their maximum hit points less that damage. The ring still heals the rest, and a potion or a cure spell still heals all of it. [`DamageDealtEvent`][osrlib.core.events.DamageDealtEvent]`.non_regenerable` is now True when fire or acid hits a wearer. The new field defaults to 0, so a save from before this change still loads and [`SCHEMA_VERSION`][osrlib.versioning.SCHEMA_VERSION] stays 4. Saves and party documents now include the field, so the golden files that contain characters were regenerated to add it.
 - *Sleep* judges a drained monster by the Hit Dice it has left, because energy drain takes Hit Dice away. Before, both of the spell's modes read the monster's template. The single-creature mode takes only a creature of exactly 4+1 Hit Dice: 4 Hit Dice with a bonus, no more and no fewer. An ogre drained from 4+1 to 3+1 Hit Dice is no longer a 4+1 creature, so this mode now has no effect on it. Before, the mode put that ogre to sleep. The 2d8 Hit Dice mode takes creatures of 4 Hit Dice or fewer and leaves out 4+1 creatures. It now takes the drained ogre for 3 Hit Dice of its budget. Before, it left the ogre out as a 4+1 creature. This fix covers the 4+1 test in both modes. The [`effective_hd`][osrlib.core.combat.effective_hd] fix below covers the rest of the 2d8 mode: what each creature costs from the budget, and whether it's under the 4 Hit Dice limit. With that fix, a 5 Hit Dice grizzly bear drained to 4 is eligible for the 2d8 mode too.
+- Three more rules judge a drained monster by the Hit Dice it has left, because energy drain takes Hit Dice away. Before, each used the monster's template. *Confusion*'s re-save each round uses the drained count, so a 3 Hit Dice boar drained to 2 Hit Dice is a subject of 2 Hit Dice and no longer saves. The Hit Dice bands of the protection scrolls use it too, so a 4 Hit Dice wraith drained to 3 Hit Dice counts in the 1 to 3 Hit Dice band of a scroll of protection from undead. Last, the optional rule that lets a monster of 5 Hit Dice or more harm a creature that only magic or silver can hurt uses it, so a grizzly drained from 5 to 4 Hit Dice no longer qualifies. This is [`MonsterInstance.hit_dice_count`][osrlib.core.monsters.MonsterInstance.hit_dice_count], the same count that sets its THAC0 and saves. The turning table and a monster's experience value still use the template, because the OSE SRD ties them to the kind of monster.
+- *Death spell* cast at a group with `target_group_id` now takes only the creatures its 60' cube covers. Before, the cast took every living member of the group. The cast now uses the same footprint as any other area spell in [`BattleDeclaration`][osrlib.crawl.commands.BattleDeclaration]: the group's living members in spawn order up to the footprint's capacity, then the party's front rank when `aoe_friendly_fire` applies. A cast with named `targets` still uses those targets. *Sleep* has no area in the OSE SRD, so it still takes every living member of the group.
 - When a wandering monster interrupts a rest, the full turns the party rested before the monsters came now count (#169). Before, a 48-turn night broken after four full turns cleared neither fatigue nor exhaustion. Now one full turn of rest clears fatigue. Each full turn also counts toward the three that clear exhaustion from a chase, and the next rest adds to that count. A rest interrupted during its first turn still clears nothing. An interrupted night still isn't sleep for preparing spells, and an interrupted day still heals nobody. The fix makes no new draws, and no golden file changed.
 - Trolls, thouls, and vampires regenerate in play (#167). Until this release a spawned one never healed, though its template had the ability. A monster whose template has the `regeneration` ability now starts to regenerate when its encounter opens. That's true whether the monster came from a [`SpawnMonsters`][osrlib.crawl.commands.SpawnMonsters] command, a keyed area, or a wandering-monster check. The command that opened the encounter reports an [`EffectAttachedEvent`][osrlib.core.events.EffectAttachedEvent] for each such monster. A hurt troll gets back 3 hit points a round, starting 3 rounds after it last took damage. It never gets back damage from fire or acid. A troll slain while its encounter is still running gets back up 2d6 rounds later and fights again. It stays dead if fire and acid alone did as much damage as its maximum hit points. The session rolls the revival delay on the effects stream. A thoul or a vampire heals every round while it lives. The session releases the effect when the encounter ends, so a troll that is still dead then stays dead. A game recorded under 2.0.1 that met one of these monsters replays differently under this release. No golden file changed.
 - Undead that a cleric turns now flee and attack no one, even when the cleric turns only some of a group (#168). Before, the turned members of a partly turned group kept closing and attacking, the cleric who turned them included. Now they break away as a new group, which runs from the battle the way a wholly turned group does. The session reports the split with a [`MonsterFledEvent`][osrlib.crawl.events.MonsterFledEvent] whose `group_id` is the new group's id. The members who weren't turned stay in the original group and fight on, and a policy you registered for that group still chooses their actions. The group's shared treasure stays with the members who fight on, and each turned member takes only the treasure it carries. A turned monster that can't move, such as one caught in a *web*, stays where it is and does nothing. The session skips any action a policy returns for a turned monster. A wholly turned group behaves as before, and no golden file changed.