fix(LuaEngine): Preallocate Lua stack size in PushRefsFor to prevent reallocation during push loop

[mostlynick3]

I recently ran into a problem where I ended up having so many hooks (up to 50) and functions (some 100) called on player commands that I kept getting random crashes and stack corruptions. After some troubleshooting, I found out that when the Lua stack runs out of allocated space during PushRefsFor, Lua triggers luaD_reallocstack mid-loop, moving the stack to a new memory location. This invalidates raw pointers (cl, base, k, ra) held by any luaV_execute frame on the C stack, causing a crash.

For example, this script on a clean project crashes on reaching reload conf:

local function OnCommand(event, player, command)
    if command == "test" then
        return false
    end
end
for i = 1, 500 do
    RegisterPlayerEvent(42, OnCommand)
end
CreateLuaEvent(function()
    RunCommand("reload conf")
end, 1000)

Whereas with the fix, 500 loops works correctly and I can even increase it to 50 000 without any stack corruption:

local function OnCommand(event, player, command)
    if command == "test" then
        return false
    end
end
for i = 1, 50000 do
    RegisterPlayerEvent(42, OnCommand)
end
CreateLuaEvent(function()
    RunCommand("reload conf")
end, 1000)

The fix is a single lua_checkstack(L, list.size()) call before the push loop in PushRefsFor, preallocating enough stack space for all function refs upfront so no reallocation occurs mid-loop. Now, the stack is safe until it overflows, instead of randomly corrupting.

[Copilot]

Pull request overview

This PR addresses Lua stack reallocation during BindingMap::PushRefsFor, which can lead to stack corruption/crashes when a large number of hook/function refs are pushed in a loop (e.g., many registered handlers).

Changes:

• Preallocates Lua stack capacity before pushing a binding list’s function references by calling lua_checkstack(L, list.size()).

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 2 comments.