From c1824a99035a231172f3c10ae3ee24a3e6330260 Mon Sep 17 00:00:00 2001
From: Benoit Giannangeli <benoit.giannangeli@boursorama.fr>
Date: Wed, 22 Feb 2017 07:42:36 +0100
Subject: xpcall calls msgh

---
 README.md         |  5 ++---
 src/lapi.js       | 20 +++++++++++++++++---
 src/lbaselib.js   | 10 +++++-----
 src/ldebug.js     |  2 +-
 tests/lbaselib.js | 15 ++++++++++-----
 5 files changed, 35 insertions(+), 17 deletions(-)

diff --git a/README.md b/README.md
index a7d0124..e145ed7 100644
--- a/README.md
+++ b/README.md
@@ -210,19 +210,18 @@
         - [x] type
         - [x] error
         - [x] pcall
+        - [x] xpcall
+        - [x] collectgarbage (unavailable)
         - [ ] assert
-        - [ ] collectgarbage
         - [ ] dofile
         - [ ] ipairs
         - [ ] loadfile
         - [ ] load
-        - [ ] loadstring
         - [ ] next
         - [ ] pairs
         - [ ] rawlen
         - [ ] select
         - [ ] tonumber
-        - [ ] xpcall
     - [ ] ...
 - [ ] Debug (errors)
 - [ ] DOM API binding
diff --git a/src/lapi.js b/src/lapi.js
index 9059ee9..c091150 100644
--- a/src/lapi.js
+++ b/src/lapi.js
@@ -548,9 +548,9 @@ const lua_pcallk = function(L, nargs, nresults, errfunc, ctx, k) {
     if (errfunc === 0)
         func = 0;
     else {
-        let o = index2addr(L, errfunc);
+        // let o = index2addr(L, errfunc);
         // TODO: api_checkstackindex(L, errfunc, o);
-        func = errfunc;
+        func = index2addr_(L, errfunc);
     }
 
     c.funcOff = L.top - (nargs + 1); /* function to be called */
@@ -605,6 +605,17 @@ const lua_concat = function(L, n) {
     }
 };
 
+// This functions are only there for compatibility purposes
+const lua_gc = function () {};
+
+const lua_getallocf = function () {
+    console.warn("lua_getallocf is not available and will always return null");
+    return null;
+};
+const lua_getextraspace = function () {
+    console.warn("lua_getextraspace is not available and will always return null");
+    return null;
+};
 
 module.exports.lua_pushvalue       = lua_pushvalue;
 module.exports.lua_pushnil         = lua_pushnil;
@@ -659,4 +670,7 @@ module.exports.lua_settop          = lua_settop;
 module.exports.lua_rawequal        = lua_rawequal;
 module.exports.lua_concat          = lua_concat;
 module.exports.lua_error           = lua_error;
-module.exports.lua_insert          = lua_insert;
\ No newline at end of file
+module.exports.lua_insert          = lua_insert;
+module.exports.lua_gc              = lua_gc;
+module.exports.lua_getallocf       = lua_getallocf;
+module.exports.lua_getextraspace   = lua_getextraspace;
\ No newline at end of file
diff --git a/src/lbaselib.js b/src/lbaselib.js
index ac0ac4c..b3dcd12 100644
--- a/src/lbaselib.js
+++ b/src/lbaselib.js
@@ -131,10 +131,10 @@ const luaB_pcall = function(L) {
 */
 const luaB_xpcall = function(L) {
     let n = lapi.lua_gettop(L);
-    lauxlib.luaL_checktype(L, 2, CT.LUA_TFUNCTION);
-    lapi.lua_pushboolean(L, 1);
-    lapi.lua_pushvalue(L, 1);
-    lapi.lua_rotate(L, 3, 2);
+    lauxlib.luaL_checktype(L, 2, CT.LUA_TFUNCTION);  /* check error function */
+    lapi.lua_pushboolean(L, 1);  /* first result */
+    lapi.lua_pushvalue(L, 1);  /* function */
+    lapi.lua_rotate(L, 3, 2);  /* move them below function's arguments */
     let status = lapi.lua_pcallk(L, n - 2, lua.LUA_MULTRET, 2, 2, finishpcall);
     return finishpcall(L, status, 2);
 };
@@ -167,4 +167,4 @@ const luaopen_base = function(L) {
     return 1;
 };
 
-module.exports.luaopen_base      = luaopen_base;
+module.exports.luaopen_base = luaopen_base;
diff --git a/src/ldebug.js b/src/ldebug.js
index be122e0..f6d0633 100644
--- a/src/ldebug.js
+++ b/src/ldebug.js
@@ -485,7 +485,7 @@ const luaG_errormsg = function(L) {
     if (L.errfunc !== 0) {  /* is there an error handling function? */
         let errfunc = L.errfunc;
         L.stack[L.top] = L.stack[L.top - 1];
-        L.stack[L.top - 1] = errfunc;
+        L.stack[L.top - 1] = L.stack[errfunc];
         L.top++;
         ldo.luaD_callnoyield(L, L.top - 2, 1);
     }
diff --git a/tests/lbaselib.js b/tests/lbaselib.js
index cca3ebe..85563da 100644
--- a/tests/lbaselib.js
+++ b/tests/lbaselib.js
@@ -338,7 +338,7 @@ test('xpcall', function (t) {
         return xpcall(willFail, msgh)
     `, L;
     
-    t.plan(1);
+    t.plan(3);
 
     t.doesNotThrow(function () {
 
@@ -356,8 +356,13 @@ test('xpcall', function (t) {
 
     console.log(lapi.lua_tostring(L, -1));
 
-    // t.ok(
-    //     lapi.lua_tostring(L, -1).endsWith("you fucked up"),
-    //     "Error is on the stack"
-    // )
+    t.ok(
+        lapi.lua_tostring(L, -1).startsWith("Something's wrong:"),
+        "msgh was called and modified the error"
+    )
+
+    t.ok(
+        lapi.lua_tostring(L, -1).endsWith("you fucked up"),
+        "msgh was called and modified the error"
+    )
 });
\ No newline at end of file
-- 
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