From 837c0d97178f2a4734bac74a991cc90443818878 Mon Sep 17 00:00:00 2001
From: Daniel Yates <me@meorawr.io>
Date: Wed, 31 Aug 2022 20:48:35 +0100
Subject: [PATCH] Fix default end index for table.concat and unpack

These were broken in commit 836a38aaef7dedcf46389b0f94267507e5469f8f
which removed deprecated APIs and - accidentally - replaced the index
from which the length of the table is calculated to use the `i`
parameter as a stack index, instead of a literal "1".
---
 CHANGELOG.md      | 3 ++-
 liblua/lbaselib.c | 2 +-
 liblua/ltablib.c  | 2 +-
 3 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index b484ed7..7cc555d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,8 +1,9 @@
 # Changelog
 
-## [Unreleased]
+## [v2.1]
 ### Changed
 - The `lua_Clock` typedef is now an `int64_t` to work around issues on 32-bit platforms.
+- Fixed a bug with `table.concat` and `unpack` using an incorrect default value for the optional `j` parameter.
 
 ## [v2.0]
 ### Added
diff --git a/liblua/lbaselib.c b/liblua/lbaselib.c
index e6b6405..68eacdc 100644
--- a/liblua/lbaselib.c
+++ b/liblua/lbaselib.c
@@ -328,7 +328,7 @@ static int luaB_unpack (lua_State *L) {
     int n;
     luaL_checktype(L, 1, LUA_TTABLE);
     i = luaL_optint(L, 2, 1);
-    e = luaL_opt(L, luaL_checkint, 3, (int) lua_objlen(L, i));
+    e = luaL_opt(L, luaL_checkint, 3, (int) lua_objlen(L, 1));
     if (i > e) {
         return 0; /* empty range */
     }
diff --git a/liblua/ltablib.c b/liblua/ltablib.c
index 33fd03b..3160fb1 100644
--- a/liblua/ltablib.c
+++ b/liblua/ltablib.c
@@ -134,7 +134,7 @@ static int table_concat (lua_State *L) {
     const char *sep = luaL_optlstring(L, 2, "", &lsep);
     luaL_checktype(L, 1, LUA_TTABLE);
     i = luaL_optint(L, 3, 1);
-    last = luaL_opt(L, luaL_checkint, 4, (int) lua_objlen(L, i));
+    last = luaL_opt(L, luaL_checkint, 4, (int) lua_objlen(L, 1));
     luaL_buffinit(L, &b);
     for (; i < last; i++) {
         addfield(L, &b, i);