From f0806a6d6255ee440d703ea472a033c8d4eed881 Mon Sep 17 00:00:00 2001
From: Alex Orlenko <zxteam@protonmail.com>
Date: Wed, 13 Aug 2025 22:49:40 +0100
Subject: [PATCH] Lower fastpath table creation limit to 1 << 26 When Lua is
 configured without memory restrictions, we use fastpath for table creation
 (unprotected mode). In generally it's safe as long as we `abort()` on
 allocation failure. However some Lua versions have additional restrictions on
 table size that we need to adhere in mlua too. Probably Luau has the lowest
 limits. Fixes #627

---
 src/util/mod.rs | 2 +-
 tests/table.rs  | 9 +++++++++
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/src/util/mod.rs b/src/util/mod.rs
index b69a867..4d07d3c 100644
--- a/src/util/mod.rs
+++ b/src/util/mod.rs
@@ -122,7 +122,7 @@ pub(crate) unsafe fn push_table(
 ) -> Result<()> {
     let narr: c_int = narr.try_into().unwrap_or(c_int::MAX);
     let nrec: c_int = nrec.try_into().unwrap_or(c_int::MAX);
-    if protect || narr >= const { 1 << 30 } || nrec >= const { 1 << 27 } {
+    if protect || narr >= const { 1 << 26 } || nrec >= const { 1 << 26 } {
         protect_lua!(state, 0, 1, |state| ffi::lua_createtable(state, narr, nrec))
     } else {
         ffi::lua_createtable(state, narr, nrec);
diff --git a/tests/table.rs b/tests/table.rs
index 3d4f5ef..922da8d 100644
--- a/tests/table.rs
+++ b/tests/table.rs
@@ -61,6 +61,15 @@ fn test_table() -> Result<()> {
     Ok(())
 }
 
+#[test]
+#[cfg(target_os = "linux")] // Linux allow overcommiting the memory (relevant for CI)
+fn test_table_with_large_capacity() {
+    let lua = Lua::new();
+
+    let t = lua.create_table_with_capacity(1 << 26, 1 << 26);
+    assert!(t.is_ok());
+}
+
 #[test]
 fn test_table_push_pop() -> Result<()> {
     let lua = Lua::new();