Fix two latent Ground Zero bugs: random-respawn dmflag filters and tesla retargeting

src/g_newdm.c

@@ -17,6 +17,7 @@ extern qboolean Pickup_Health(edict_t *ent, edict_t *other);
 extern qboolean Pickup_Adrenaline(edict_t *ent, edict_t *other);
 extern qboolean Pickup_Armor(edict_t *ent, edict_t *other);
 extern qboolean Pickup_PowerArmor(edict_t *ent, edict_t *other);
+extern qboolean Pickup_Sphere(edict_t *ent, edict_t *other);
 extern edict_t *Sphere_Spawn(edict_t *owner, int spawnflags);
 extern void ED_CallSpawn(edict_t *ent);
 void fire_doppleganger(edict_t *ent, vec3_t start, vec3_t aimdir);
@@ -68,6 +69,39 @@ InitGameRules(void)
 	}
 }
 
+/*
+ * These dmflag filters decide which item may be substituted IN, so they test
+ * the candidate item.  The original tested ent->classname, the item being
+ * replaced, which is loop invariant and the inverse of what the comment on the
+ * sphere filter says: a disabled sphere respawned as itself, while every other
+ * item could still be substituted into one.  Both passes share this predicate
+ * so that the counting pass and the picking pass cannot disagree on which
+ * items are eligible.
+ */
+static qboolean
+SubstituteItemAllowed(const gitem_t *it)
+{
+	/* don't respawn spheres if they're dmflag disabled. */
+	if (((int)dmflags->value & DF_NO_SPHERES) && (it->pickup == Pickup_Sphere))
+	{
+		return false;
+	}
+
+	if (((int)dmflags->value & DF_NO_NUKES) &&
+		!strcmp(it->classname, "ammo_nuke"))
+	{
+		return false;
+	}
+
+	if (((int)dmflags->value & DF_NO_MINES) &&
+		(!strcmp(it->classname, "ammo_prox") || !strcmp(it->classname, "ammo_tesla")))
+	{
+		return false;
+	}
+
+	return true;
+}
+
 const char *
 FindSubstituteItem(edict_t *ent)
 {
@@ -168,25 +202,7 @@ FindSubstituteItem(edict_t *ent)
 			itflags = IT_AMMO;
 		}
 
-		/* don't respawn spheres if they're dmflag disabled. */
-		if ((int)dmflags->value & DF_NO_SPHERES)
-		{
-			if (!strcmp(ent->classname, "item_sphere_vengeance") ||
-				!strcmp(ent->classname, "item_sphere_hunter") ||
-				!strcmp(ent->classname, "item_spehre_defender"))
-			{
-				continue;
-			}
-		}
-
-		if (((int)dmflags->value & DF_NO_NUKES) &&
-			!strcmp(ent->classname, "ammo_nuke"))
-		{
-			continue;
-		}
-
-		if (((int)dmflags->value & DF_NO_MINES) &&
-			(!strcmp(ent->classname, "ammo_prox") || !strcmp(ent->classname, "ammo_tesla")))
+		if (!SubstituteItemAllowed(it))
 		{
 			continue;
 		}
@@ -223,14 +239,7 @@ FindSubstituteItem(edict_t *ent)
 			itflags = IT_AMMO;
 		}
 
-		if (((int)dmflags->value & DF_NO_NUKES) &&
-			!strcmp(ent->classname, "ammo_nuke"))
-		{
-			continue;
-		}
-
-		if (((int)dmflags->value & DF_NO_MINES) &&
-			(!strcmp(ent->classname, "ammo_prox") || !strcmp(ent->classname, "ammo_tesla")))
+		if (!SubstituteItemAllowed(it))
 		{
 			continue;
 		}

src/monster/misc/move.c

@@ -447,8 +447,14 @@ SV_movestep(edict_t *ent, vec3_t move, qboolean relink)
 		{
 			if (new_bad->owner && !strcmp(new_bad->owner->classname, "tesla"))
 			{
+				/* A monster that is already angry at a tesla is left alone.
+				   The original guarded that case with a misspelled "telsa",
+				   so the branch never ran and the monster was retargeted at
+				   the blocking tesla instead, which is the behaviour this
+				   condition inherited when the chain was collapsed. */
 				if (!ent->enemy || !ent->enemy->inuse ||
-					!ent->enemy->client || !visible(ent, ent->enemy))
+					(strcmp(ent->enemy->classname, "tesla") &&
+					 (!ent->enemy->client || !visible(ent, ent->enemy))))
 				{
 					TargetTesla(ent, new_bad->owner);
 					ent->monsterinfo.aiflags |= AI_BLOCKED;