commit 0238a0b01e042fad472a60138162209431b8e703
parent 1ae0b6c0bf9c389bcf9bdf266591cb1e17e80a15
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Tue, 21 Mar 2006 16:30:46 -0300
BUG: luaL_checkudata may show wrong error message
Diffstat:
| M | bugs | | | 38 | ++++++++++++++++++++++++++++++++++++++ |
| M | lauxlib.c | | | 18 | ++++++++++++------ |
2 files changed, 50 insertions(+), 6 deletions(-)
diff --git a/bugs b/bugs
@@ -839,3 +839,41 @@ patch = [[
}
+
+Bug{
+what = [[luaL_checkudata may produce wrong error message]],
+
+report = [[Greg Falcon, 21/03/2006]],
+
+example = [[
+getmetatable(io.stdin).__gc()
+ --> bad argument #1 to '__gc' (FILE* expected, got table)
+]],
+
+patch = [[
+* lauxlib.c:
+@@ -123,11 +123,17 @@
+
+ LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) {
+ void *p = lua_touserdata(L, ud);
+- lua_getfield(L, LUA_REGISTRYINDEX, tname); /* get correct metatable */
+- if (p == NULL || !lua_getmetatable(L, ud) || !lua_rawequal(L, -1, -2))
+- luaL_typerror(L, ud, tname);
+- lua_pop(L, 2); /* remove both metatables */
+- return p;
++ if (p != NULL) { /* value is a userdata? */
++ if (lua_getmetatable(L, ud)) { /* does it have a metatable? */
++ lua_getfield(L, LUA_REGISTRYINDEX, tname); /* get correct metatable */
++ if (lua_rawequal(L, -1, -2)) { /* does it have the correct mt? */
++ lua_pop(L, 2); /* remove both metatables */
++ return p;
++ }
++ }
++ }
++ luaL_typerror(L, ud, tname); /* else error */
++ return NULL; /* to avoid warnings */
+ }
+]]
+
+}
+
diff --git a/lauxlib.c b/lauxlib.c
@@ -1,5 +1,5 @@
/*
-** $Id: lauxlib.c,v 1.157 2005/12/29 15:32:11 roberto Exp roberto $
+** $Id: lauxlib.c,v 1.158 2006/01/16 12:42:21 roberto Exp roberto $
** Auxiliary functions for building Lua libraries
** See Copyright Notice in lua.h
*/
@@ -123,11 +123,17 @@ LUALIB_API int luaL_newmetatable (lua_State *L, const char *tname) {
LUALIB_API void *luaL_checkudata (lua_State *L, int ud, const char *tname) {
void *p = lua_touserdata(L, ud);
- lua_getfield(L, LUA_REGISTRYINDEX, tname); /* get correct metatable */
- if (p == NULL || !lua_getmetatable(L, ud) || !lua_rawequal(L, -1, -2))
- luaL_typerror(L, ud, tname);
- lua_pop(L, 2); /* remove both metatables */
- return p;
+ if (p != NULL) { /* value is a userdata? */
+ if (lua_getmetatable(L, ud)) { /* does it have a metatable? */
+ lua_getfield(L, LUA_REGISTRYINDEX, tname); /* get correct metatable */
+ if (lua_rawequal(L, -1, -2)) { /* does it have the correct mt? */
+ lua_pop(L, 2); /* remove both metatables */
+ return p;
+ }
+ }
+ }
+ luaL_typerror(L, ud, tname); /* else error */
+ return NULL; /* to avoid warnings */
}
