Fix possible crash in IsPlayerCanDiscardDeckAsCost with count of 0

If 0 was passed as count, and the checked player had no cards in his deck, and a EFFECT_TO_GRAVE_REDIRECT was applied, the core would've crashed
edo9300 · Dec 21, 2023 · 48a4ecf · 48a4ecf
1 parent 8b5c5d9
commit 48a4ecf
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Showing 3 changed files with 10 additions and 11 deletions.
diff --git a/field.cpp b/field.cpp
@@ -2618,16 +2618,18 @@ int32_t field::check_with_sum_greater_limit_m(const card_vector& mats, int32_t a
 int32_t field::is_player_can_draw(uint8_t playerid) {
 	return !is_player_affected_by_effect(playerid, EFFECT_CANNOT_DRAW);
 }
-int32_t field::is_player_can_discard_deck(uint8_t playerid, int32_t count) {
-	if(player[playerid].list_main.size() < (uint32_t)count)
+int32_t field::is_player_can_discard_deck(uint8_t playerid, uint32_t count) {
+	if(player[playerid].list_main.size() < count)
 		return FALSE;
 	return !is_player_affected_by_effect(playerid, EFFECT_CANNOT_DISCARD_DECK);
 }
-int32_t field::is_player_can_discard_deck_as_cost(uint8_t playerid, int32_t count) {
-	if(player[playerid].list_main.size() < (uint32_t)count)
+int32_t field::is_player_can_discard_deck_as_cost(uint8_t playerid, uint32_t count) {
+	if(player[playerid].list_main.size() < count)
 		return FALSE;
 	if(is_player_affected_by_effect(playerid, EFFECT_CANNOT_DISCARD_DECK))
 		return FALSE;
+	if(player[playerid].list_main.empty())
+		return TRUE;
 	card* topcard = player[playerid].list_main.back();
 	if((count == 1) && topcard->is_position(POS_FACEUP))
 		return topcard->is_capable_cost_to_grave(playerid);

diff --git a/field.h b/field.h
@@ -529,8 +529,8 @@ class field {
 	static int32_t check_with_sum_greater_limit_m(const card_vector& mats, int32_t acc, int32_t index, int32_t opmin, int32_t must_count, int32_t* should_continue);
 
 	int32_t is_player_can_draw(uint8_t playerid);
-	int32_t is_player_can_discard_deck(uint8_t playerid, int32_t count);
-	int32_t is_player_can_discard_deck_as_cost(uint8_t playerid, int32_t count);
+	int32_t is_player_can_discard_deck(uint8_t playerid, uint32_t count);
+	int32_t is_player_can_discard_deck_as_cost(uint8_t playerid, uint32_t count);
 	int32_t is_player_can_discard_hand(uint8_t playerid, card* pcard, effect* peffect, uint32_t reason);
 	int32_t is_player_can_action(uint8_t playerid, uint32_t actionlimit);
 	int32_t is_player_can_summon(uint32_t sumtype, uint8_t playerid, card* pcard, uint8_t toplayer);

diff --git a/libduel.cpp b/libduel.cpp
@@ -3596,11 +3596,8 @@ LUA_STATIC_FUNCTION(IsPlayerCanDraw) {
 		return 1;
 	}
 	auto count = lua_get<uint32_t, 0>(L, 2);
-	if(count == 0)
-		lua_pushboolean(L, pduel->game_field->is_player_can_draw(playerid));
-	else
-		lua_pushboolean(L, pduel->game_field->is_player_can_draw(playerid)
-		                && (pduel->game_field->player[playerid].list_main.size() >= count));
+	lua_pushboolean(L, pduel->game_field->is_player_can_draw(playerid)
+					&& (pduel->game_field->player[playerid].list_main.size() >= count));
 	return 1;
 }
 LUA_STATIC_FUNCTION(IsPlayerCanDiscardDeck) {