From 1a3ee5a8a18d3c1b7db54f3b4875e1dda9a0769f Mon Sep 17 00:00:00 2001
From: lihongyan <lihongyan@statsape.com>
Date: Fri, 7 Aug 2026 17:11:26 +0800
Subject: [PATCH] Fix tcc.load(): home_path variable, pcall handle, metatype
 idempotency

Three bugs in tcc.load() made it unusable with a home_path and made
repeated calls crash:

1. tcc.home_path was assigned the undefined variable `tccdir` instead of
   the `home_path` parameter, silently discarding the provided path.
2. clib = pcall(ffi.load(...)) stored the *boolean* success flag into
   tcc.clib instead of the library handle, so tcc.clib.tcc_new() failed
   with 'cannot convert bool to struct TCCState *'.
3. ffi.metatype("TCCState", ...) was called unconditionally on every
   load; the second call raises 'cannot change a protected metatable'.
   Guarded with pcall so tcc.load() is idempotent.

Also fixed tcc.new(): the body referenced `tcc.tccdir` (undefined) and
the parameter `addpaths` (typo, missing underscore), so the home path
setup branch never ran.
---
 tcc.lua | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/tcc.lua b/tcc.lua
index a6e43d7..0188803 100644
--- a/tcc.lua
+++ b/tcc.lua
@@ -48,7 +48,7 @@ tcc.clib = nil
 --local tcc = require("tcc").load("tcc", "/lib/tcc")
 function tcc.load(lib, home_path)
   if home_path then
-    tcc.home_path = tccdir
+    tcc.home_path = home_path
   else
     tcc.home_path = os.getenv("CONFIG_TCCDIR") or tcc.home_path
   end
@@ -78,11 +78,16 @@ function tcc.load(lib, home_path)
     int tcc_relocate(TCCState *s1, void *ptr);
     void *tcc_get_symbol(TCCState *s, const char *name);
   ]])
-  ffi.metatype("TCCState", tcc.State)
+  -- ffi.metatype fails on the second call: once a metatype is set it becomes
+  -- protected and cannot be changed ("cannot change a protected metatable").
+  -- Guard it so tcc.load() is idempotent and can be called more than once
+  -- (e.g. from several modules or after a failed first load).
+  pcall(ffi.metatype, "TCCState", tcc.State)
 
   local clib
   if tcc.home_path then
-    clib = pcall(ffi.load(("%s/%s"):format(tcc.home_path, lib)))
+    local ok_load, lib_handle = pcall(ffi.load, ("%s/%s"):format(tcc.home_path, lib))
+    clib = ok_load and lib_handle or nil
   end
   if not clib then
     clib = ffi.load(lib)
@@ -102,10 +107,10 @@ end
 function tcc.new(add_paths)
   local state = tcc.clib.tcc_new()
   ffi.gc(state, tcc.State.__gc)
-  if addpaths ~= false and tcc.tccdir then
-    state:set_home_path(tcc.tccdir)
-    state:add_sysinclude_path(tcc.tccdir .. "/include")
-    state:add_library_path(tcc.tccdir .. "/lib")
+  if add_paths ~= false and tcc.home_path then
+    state:set_home_path(tcc.home_path)
+    state:add_sysinclude_path(tcc.home_path .. "/include")
+    state:add_library_path(tcc.home_path .. "/lib")
   end
   return state
 end