Don't lose your heads over infinite loops (#35808)

data/json/effects.json

@@ -16,6 +16,12 @@
     "name": [ "Ridden" ],
     "desc": [ "AI tag for when critter is being ridden. This is a bug if you have it." ]
   },
+  {
+    "type": "effect_type",
+    "id": "npc_suspend",
+    "name": [ "npc_suspend" ],
+    "desc": [ "AI tag for when an NPC needs to be rebooted after an infinite loop." ]
+  },
   {
     "type": "effect_type",
     "id": "harnessed",

data/json/npcs/TALK_COMMON_ALLY.json

@@ -27,6 +27,15 @@
       { "text": "Go back to sleep.", "topic": "TALK_DONE" }
     ]
   },
+  {
+    "id": "TALK_REBOOT",
+    "type": "talk_topic",
+    "dynamic_line": "This character was previously put into a suspension state due to an AI bug. If you have reason to believe the problem was fixed, you can wake them up. Do you want to do that now?",
+    "responses": [
+      { "text": "yes, wake up!", "topic": "TALK_NONE", "effect": "wake_up" },
+      { "text": "no, go back to sleep.", "topic": "TALK_DONE" }
+    ]
+  },
   {
     "id": [ "TALK_FRIEND", "TALK_GIVE_ITEM", "TALK_USE_ITEM", "TALK_RADIO" ],
     "type": "talk_topic",

src/creature.cpp

@@ -45,6 +45,7 @@ const efftype_id effect_blind( "blind" );
 const efftype_id effect_bounced( "bounced" );
 const efftype_id effect_downed( "downed" );
 const efftype_id effect_onfire( "onfire" );
+const efftype_id effect_npc_suspend( "npc_suspend" );
 const efftype_id effect_sap( "sap" );
 const efftype_id effect_sleep( "sleep" );
 const efftype_id effect_stunned( "stunned" );
@@ -1301,7 +1302,8 @@ void Creature::set_moves( int nmoves )
 
 bool Creature::in_sleep_state() const
 {
-    return has_effect( effect_sleep ) || has_effect( effect_lying_down );
+    return has_effect( effect_sleep ) || has_effect( effect_lying_down ) ||
+           has_effect( effect_npc_suspend );
 }
 
 /*

src/game.cpp

@@ -205,6 +205,7 @@ const efftype_id effect_hot( "hot" );
 const efftype_id effect_infected( "infected" );
 const efftype_id effect_laserlocked( "laserlocked" );
 const efftype_id effect_no_sight( "no_sight" );
+const efftype_id effect_npc_suspend( "npc_suspend" );
 const efftype_id effect_onfire( "onfire" );
 const efftype_id effect_pacified( "pacified" );
 const efftype_id effect_paid( "paid" );
@@ -4242,7 +4243,9 @@ void game::monmove()
     for( npc &guy : g->all_npcs() ) {
         int turns = 0;
         m.creature_in_field( guy );
-        guy.process_turn();
+        if( !guy.has_effect( effect_npc_suspend ) ) {
+            guy.process_turn();
+        }
         while( !guy.is_dead() && ( !guy.in_sleep_state() || guy.activity.id() == "ACT_OPERATION" ) &&
                guy.moves > 0 && turns < 10 ) {
             int moves = guy.moves;
@@ -4263,10 +4266,10 @@ void game::monmove()
         }
 
         // If we spun too long trying to decide what to do (without spending moves),
-        // Invoke cranial detonation to prevent an infinite loop.
+        // Invoke cognitive suspension to prevent an infinite loop.
         if( turns == 10 ) {
-            add_msg( _( "%s's brain explodes!" ), guy.name );
-            guy.die( nullptr );
+            add_msg( _( "%s faints!" ), guy.name );
+            guy.reboot();
         }
 
         if( !guy.is_dead() ) {

src/npc.cpp

@@ -99,6 +99,7 @@ const efftype_id effect_high( "high" );
 const efftype_id effect_pkill1( "pkill1" );
 const efftype_id effect_pkill2( "pkill2" );
 const efftype_id effect_pkill3( "pkill3" );
+const efftype_id effect_npc_suspend( "npc_suspend" );
 const efftype_id effect_pkill_l( "pkill_l" );
 const efftype_id effect_infection( "infection" );
 const efftype_id effect_bouldering( "bouldering" );
@@ -2375,6 +2376,45 @@ bool npc::is_dead() const
     return dead || is_dead_state();
 }
 
+void npc::reboot()
+{
+    //The NPC got into an infinite loop, in game.cpp  -monmove() - a debugmsg just popped up
+    // informing player of this.
+    // put them to sleep and reboot their brain.
+    // they can be woken up by the player, and if their brain is fixed, great,
+    // if not, they will faint again, and the NPC can be kept asleep until the bug is fixed.
+    cancel_activity();
+    path.clear();
+    last_player_seen_pos = cata::nullopt;
+    last_seen_player_turn = 999;
+    wanted_item_pos = no_goal_point;
+    guard_pos = no_goal_point;
+    goal = no_goal_point;
+    fetching_item = false;
+    has_new_items = true;
+    worst_item_value = 0;
+    mission = NPC_MISSION_NULL;
+    patience = 0;
+    ai_cache.danger = 0;
+    ai_cache.total_danger = 0;
+    ai_cache.danger_assessment = 0;
+    ai_cache.target.reset();
+    ai_cache.ally.reset();
+    ai_cache.can_heal.clear_all();
+    ai_cache.sound_alerts.clear();
+    ai_cache.s_abs_pos = tripoint_zero;
+    ai_cache.stuck = 0;
+    ai_cache.guard_pos = cata::nullopt;
+    ai_cache.my_weapon_value = 0;
+    ai_cache.friends.clear();
+    ai_cache.dangerous_explosives.clear();
+    ai_cache.threat_map.clear();
+    ai_cache.searched_tiles.clear();
+    activity = player_activity();
+    clear_destination();
+    add_effect( effect_npc_suspend, 24_hours, num_bp, true, 1 );
+}
+
 void npc::die( Creature *nkiller )
 {
     if( dead ) {

src/npc.h

@@ -966,6 +966,7 @@ class npc : public player
         }
         void say( const std::string &line, int priority = 0 ) const;
         void decide_needs();
+        void reboot();
         void die( Creature *killer ) override;
         bool is_dead() const;
         // How well we smash terrain (not corpses!)

src/npcmove.cpp

@@ -677,6 +677,9 @@ void npc::regen_ai_cache()
 
 void npc::move()
 {
+    // dont just return from this function without doing something
+    // that will eventually subtract moves, or change the NPC to a different type of action.
+    // because this will result in an infinite loop
     if( attitude == NPCATT_FLEE ) {
         set_attitude( NPCATT_FLEE_TEMP );  // Only run for so many hours
     } else if( attitude == NPCATT_FLEE_TEMP && !has_effect( effect_npc_flee_player ) ) {

src/npctalk.cpp

@@ -92,6 +92,7 @@ const efftype_id effect_infected( "infected" );
 const efftype_id effect_infection( "infection" );
 const efftype_id effect_lying_down( "lying_down" );
 const efftype_id effect_narcosis( "narcosis" );
+const efftype_id effect_npc_suspend( "npc_suspend" );
 const efftype_id effect_sleep( "sleep" );
 const efftype_id effect_under_op( "under_operation" );
 const efftype_id effect_riding( "riding" );
@@ -755,6 +756,9 @@ void npc::talk_to_u( bool text_only, bool radio_contact )
     }
 
     // Needs
+    if( has_effect( effect_npc_suspend ) ) {
+        d.add_topic( "TALK_REBOOT" );
+    }
     if( has_effect( effect_sleep ) || has_effect( effect_lying_down ) ) {
         if( has_effect( effect_narcosis ) ) {
             d.add_topic( "TALK_SEDATED" );

src/npctalk_funcs.cpp

@@ -66,6 +66,7 @@ const efftype_id effect_bleed( "bleed" );
 const efftype_id effect_currently_busy( "currently_busy" );
 const efftype_id effect_infected( "infected" );
 const efftype_id effect_lying_down( "lying_down" );
+const efftype_id effect_npc_suspend( "npc_suspend" );
 const efftype_id effect_sleep( "sleep" );
 const efftype_id effect_pet( "pet" );
 const efftype_id effect_controlled( "controlled" );
@@ -422,6 +423,7 @@ void talk_function::wake_up( npc &p )
     p.rules.enable_override( ally_rule::allow_sleep );
     p.remove_effect( effect_allow_sleep );
     p.remove_effect( effect_lying_down );
+    p.remove_effect( effect_npc_suspend );
     p.remove_effect( effect_sleep );
     // TODO: Get mad at player for waking us up unless we're in danger
 }