From 0a18fe6cd3cbc288774b83b9223a284f8832c703 Mon Sep 17 00:00:00 2001
From: Thomas Goyne <plorkyeran@aegisub.org>
Date: Wed, 24 Dec 2014 16:24:51 -0800
Subject: [PATCH] Fix stack corruption when a script tries to select an invalid
 line

---
 libaegisub/include/libaegisub/lua/utils.h | 22 +++++++++++++---------
 1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/libaegisub/include/libaegisub/lua/utils.h b/libaegisub/include/libaegisub/lua/utils.h
index 634d9246b..3bf8b2d9a 100644
--- a/libaegisub/include/libaegisub/lua/utils.h
+++ b/libaegisub/include/libaegisub/lua/utils.h
@@ -140,16 +140,20 @@ struct LuaForEachBreak {};
 
 template<typename Func>
 void lua_for_each(lua_State *L, Func&& func) {
-	lua_pushnil(L); // initial key
-	while (lua_next(L, -2)) {
-		try {
-			func();
+	{
+		LuaStackcheck stackcheck(L);
+		lua_pushnil(L); // initial key
+		while (lua_next(L, -2)) {
+			try {
+				func();
+			}
+			catch (LuaForEachBreak) {
+				lua_pop(L, 2); // pop value and key
+				break;
+			}
+			lua_pop(L, 1); // pop value, leave key
 		}
-		catch (LuaForEachBreak) {
-			lua_pop(L, 1);
-			break;
-		}
-		lua_pop(L, 1); // pop value, leave key
+		stackcheck.check_stack(0);
 	}
 	lua_pop(L, 1); // pop table
 }