Tidy up some web/net behaviour

Monsters should now try to escape from Arachne's
ensnare immediately (on whatever incredibly rare
occasions that is relevant), and shouldn't try to
break out of net traps on the turn they get netted.

This technically breaks save compat with the old
newly_webbed prop, but in a harmless way.

1 files changed, 23 insertions, 9 deletions

diff --git a/crawl-ref/source/traps.cc b/crawl-ref/source/traps.cc
index 39d77539e6..7507bea08e 100644
--- a/crawl-ref/source/traps.cc
+++ b/crawl-ref/source/traps.cc
@@ -323,10 +323,17 @@ static void _mark_net_trapping(const coord_def& where)
     }
 }
 
-void monster_caught_in_net(monster* mon, actor* agent)
+/**
+ * Attempt to trap a monster in a net.
+ *
+ * @param mon       The monster being trapped.
+ * @param agent     The entity doing the trapping.
+ * @return          Whether the monster was successfully trapped.
+ */
+bool monster_caught_in_net(monster* mon, actor* agent)
 {
     if (mon->body_size(PSIZE_BODY) >= SIZE_GIANT)
-        return;
+        return false;
 
     if (mons_class_is_stationary(mon->type))
     {
@@ -340,7 +347,7 @@ void monster_caught_in_net(monster* mon, actor* agent)
             else
                 mpr("The net is caught on something unseen!");
         }
-        return;
+        return false;
     }
 
     if (mon->is_insubstantial())
@@ -350,19 +357,19 @@ void monster_caught_in_net(monster* mon, actor* agent)
             mprf("The net passes right through %s!",
                  mon->name(DESC_THE).c_str());
         }
-        return;
+        return false;
     }
 
     if (mon->flight_mode() && !mons_is_confused(mon) && one_chance_in(3))
     {
         simple_monster_message(mon, " darts out from under the net!");
-        return;
+        return false;
     }
 
     if (mon->type == MONS_OOZE || mon->type == MONS_PULSATING_LUMP)
     {
         simple_monster_message(mon, " oozes right through the net!");
-        return;
+        return false;
     }
 
     if (!mon->caught() && mon->add_ench(ENCH_HELD))
@@ -371,7 +378,10 @@ void monster_caught_in_net(monster* mon, actor* agent)
             mpr("Something gets caught in the net!");
         else
             simple_monster_message(mon, " is caught in the net!");
+        return true;
     }
+
+    return false;
 }
 
 bool player_caught_in_net()
@@ -798,7 +808,12 @@ void trap_def::trigger(actor& triggerer, bool flat_footed)
                         mpr("A large net falls down!");
                 }
 
-                monster_caught_in_net(m, NULL);
+                // actually try to net the monster
+                if (monster_caught_in_net(m, NULL))
+                {
+                    // Don't try to escape the net in the same turn
+                    m->props[NEWLY_TRAPPED_KEY] = true;
+                }
             }
 
             if (triggered)
@@ -879,7 +894,7 @@ void trap_def::trigger(actor& triggerer, bool flat_footed)
                 m->add_ench(ENCH_HELD);
 
                 // Don't try to escape the web in the same turn
-                m->props[NEW_WEB_KEY] = true;
+                m->props[NEWLY_TRAPPED_KEY] = true;
 
                 // Alert monsters.
                 check_monsters_sense(SENSE_WEB_VIBRATION, 100, triggerer.position);
@@ -2017,7 +2032,6 @@ bool ensnare(actor *fly)
     {
         simple_monster_message(fly->as_monster(), " is caught in a web!");
         fly->as_monster()->add_ench(ENCH_HELD);
-        fly->props[NEW_WEB_KEY] = true;
     }
 
     // Drowned?