debug.traceback

7 files changed, 219 insertions, 20 deletions

diff --git a/README.md b/README.md
index cb4ad18..112e227 100644
--- a/README.md
+++ b/README.md
@@ -73,7 +73,6 @@
     - [ ] luaL_ref
     - [ ] luaL_setmetatable
     - [ ] luaL_testudata
-    - [ ] luaL_traceback
     - [ ] luaL_unref
 - [ ] Standard library
     - [x] Base lib
@@ -88,6 +87,7 @@
     - [ ] Debug
         - [x] debug.debug
         - [x] debug.getlocal
+        - [x] debug.traceback
         - [ ] debug.gethook
         - [ ] debug.getinfo
         - [ ] debug.getmetatable
@@ -99,7 +99,6 @@
         - [ ] debug.setmetatable
         - [ ] debug.setupvalue
         - [ ] debug.setuservalue
-        - [ ] debug.traceback
         - [ ] debug.upvalueid
         - [ ] debug.upvaluejoin
 - [ ] Run [Lua test suite](https://github.com/lua/tests)
diff --git a/src/lapi.js b/src/lapi.js
index 7f8cda8..fcb07d6 100644
--- a/src/lapi.js
+++ b/src/lapi.js
@@ -173,9 +173,8 @@ const lua_rotate = function(L, idx, n) {
 };
 
 const lua_copy = function(L, fromidx, toidx) {
-    let fr = index2addr_(L, fromidx);
-    let to = index2addr_(L, toidx);
-    L.stack[to] = fr;
+    let from = index2addr(L, fromidx);
+    L.stack[index2addr_(L, toidx)] = new TValue(from.type, from.value);
 };
 
 const lua_remove = function(L, idx) {
diff --git a/src/lauxlib.js b/src/lauxlib.js
index 03ca210..311e2eb 100644
--- a/src/lauxlib.js
+++ b/src/lauxlib.js
@@ -6,6 +6,7 @@ const assert = require('assert');
 const lstate  = require('./lstate.js');
 const lapi    = require('./lapi.js');
 const lua     = require('./lua.js');
+const char    = lua.char;
 const ldebug  = require('./ldebug.js');
 const lobject = require('./lobject.js');
 const CT      = lua.constant_types;
@@ -20,6 +21,9 @@ class luaL_Buffer {
     }
 }
 
+const LEVELS1 = 10;  /* size of the first part of the stack */
+const LEVELS2 = 11;  /* size of the second part of the stack */
+
 /*
 ** search for 'objidx' in table at index -1.
 ** return 1 + string at top if find a good name.
@@ -54,22 +58,83 @@ const findfield = function(L, objidx, level) {
 */
 const pushglobalfuncname = function(L, ar) {
     let top = lapi.lua_gettop(L);
-    ldebug.lua_getinfo(L, 'f', ar);  /* push function */
+    ldebug.lua_getinfo(L, [char['f']], ar);  /* push function */
     lapi.lua_getfield(L, lua.LUA_REGISTRYINDEX, lua.to_luastring(LUA_LOADED_TABLE));
     if (findfield(L, top + 1, 2)) {
         let name = lapi.lua_tostring(L, -1);
-        if (name.jsstring().startsWith("_G.")) {
-            lapi.lua_pushstring(L, name.slice(3));  /* name start with '_G.'? */
-            lapi.lua_remove(L, -2);  /* name start with '_G.'? */
+        if (lobject.jsstring(name).startsWith("_G.")) {  /* name start with '_G.'? */
+            lapi.lua_pushstring(L, name.slice(3));  /* push name without prefix */
+            lapi.lua_remove(L, -2);  /* remove original name */
         }
-        lapi.lua_copy(L, -1, top + 1);  /* name start with '_G.'? */
-        lapi.lua_pop(L, 2);  /* name start with '_G.'? */
+        lapi.lua_copy(L, -1, top + 1);  /* move name to proper place */
+        lapi.lua_pop(L, 2);  /* remove pushed values */
+        return 1;
     } else {
         lapi.lua_settop(L, top);  /* remove function and global table */
         return 0;
     }
 };
 
+const sv = s => s ? s : [];
+
+const pushfuncname = function(L, ar) {
+    if (pushglobalfuncname(L, ar)) {  /* try first a global name */
+        lapi.lua_pushstring(L, lua.to_luastring("function '").concat(lapi.lua_tostring(L, -1)).concat([char["'"]]));
+        lapi.lua_remove(L, -2);  /* remove name */
+    }
+    else if (ar.namewhat)  /* is there a name from code? */
+        lapi.lua_pushstring(L, sv(ar.namewhat).concat(char[" "], char["'"], ...sv(ar.name.value), char["'"]));  /* use it */
+    else if (ar.what && ar.what[0] === char['m'])  /* main? */
+        lapi.lua_pushliteral(L, "main chunk");
+    else if (ar.what && ar.what[0] != char['C'])  /* for Lua functions, use <file:line> */
+        lapi.lua_pushstring(L, lua.to_luastring("function <").concat(...sv(ar.short_src), char[':'], ...lua.to_luastring(`${ar.linedefined}>`)));
+    else  /* nothing left... */
+        lapi.lua_pushliteral(L, "?");
+};
+
+const lastlevel = function(L) {
+    let ar = new lua.lua_Debug();
+    let li = 1;
+    let le = 1;
+    /* find an upper bound */
+    while (ldebug.lua_getstack(L, le, ar)) { li = le; le *= 2; }
+    /* do a binary search */
+    while (li < le) {
+        let m = Math.floor((li + le)/2);
+        if (ldebug.lua_getstack(L, m, ar)) li = m + 1;
+        else le = m;
+    }
+    return le - 1;
+};
+
+const luaL_traceback = function(L, L1, msg, level) {
+    let ar = new lua.lua_Debug();
+    let top = lapi.lua_gettop(L);
+    let last = lastlevel(L1);
+    let n1 = last - level > LEVELS1 + LEVELS2 ? LEVELS1 : -1;
+    if (msg)
+        lapi.lua_pushstring(L, msg.concat(char['\n']));
+    luaL_checkstack(L, 10, null);
+    lapi.lua_pushliteral(L, "stack traceback:");
+    while (ldebug.lua_getstack(L1, level++, ar)) {
+        if (n1-- === 0) {  /* too many levels? */
+            lapi.lua_pushliteral(L, "\n\t...");  /* add a '...' */
+            level = last - LEVELS2 + 1;  /* and skip to last ones */
+        } else {
+            ldebug.lua_getinfo(L1, lua.to_luastring("Slnt"), ar);
+            lapi.lua_pushstring(L, [char['\n'], char['\t'], char['.'], char['.'], char['.']].concat(ar.short_src));
+            if (ar.currentline > 0)
+                lapi.lua_pushliteral(L, `${ar.currentline}:`);
+            lapi.lua_pushliteral(L, " in ");
+            pushfuncname(L, ar);
+            if (ar.istailcall)
+                lapi.lua_pushliteral(L, "\n\t(...tail calls..)");
+            lapi.lua_concat(L, lapi.lua_gettop(L) - top);
+        }
+    }
+    lapi.lua_concat(L, lapi.lua_gettop(L) - top);
+};
+
 const panic = function(L) {
     throw new Error(`PANIC: unprotected error in call to Lua API (${lapi.lua_tojsstring(L, -1)})`);
 };
@@ -82,7 +147,7 @@ const luaL_argerror = function(L, arg, extramsg) {
 
     ldebug.lua_getinfo(L, 'n', ar);
 
-    if (ar.namewhat === 'method') {
+    if (ar.namewhat === lua.to_luastring('method')) {
         arg--;  /* do not count 'self' */
         if (arg === 0)  /* error is in the self argument itself? */
             return luaL_error(L, lua.to_luastring(`calling '${lobject.jsstring(ar.name)}' on  bad self (${lobject.jsstring(extramsg)})`));
@@ -586,6 +651,7 @@ module.exports.luaL_pushresult      = luaL_pushresult;
 module.exports.luaL_requiref        = luaL_requiref;
 module.exports.luaL_setfuncs        = luaL_setfuncs;
 module.exports.luaL_tolstring       = luaL_tolstring;
+module.exports.luaL_traceback       = luaL_traceback;
 module.exports.luaL_typename        = luaL_typename;
 module.exports.luaL_where           = luaL_where;
 module.exports.lua_writestringerror = lua_writestringerror;
diff --git a/src/ldblib.js b/src/ldblib.js
index 426cef2..318e616 100644
--- a/src/ldblib.js
+++ b/src/ldblib.js
@@ -84,8 +84,23 @@ const db_upvalueid = function(L) {
    return 1;
 };
 
+const db_traceback = function(L) {
+    let thread = getthread(L);
+    let L1 = thread.thread;
+    let arg = thread.arg;
+    let msg = lapi.lua_tostring(L, arg + 1);
+    if (msg === null && !lapi.lua_isnoneornil(L, arg + 1))  /* non-string 'msg'? */
+        lapi.lua_pushvalue(L, arg + 1);  /* return it untouched */
+    else {
+        let level = lauxlib.luaL_optinteger(L, arg + 2, L === L1 ? 1 : 0);
+        lauxlib.luaL_traceback(L, L1, msg, level);
+    }
+    return 1;
+};
+
 const dblib = {
-    "getlocal": db_getlocal,
+    "getlocal":  db_getlocal,
+    "traceback": db_traceback,
     "upvalueid": db_upvalueid
 };
 
diff --git a/src/ldebug.js b/src/ldebug.js
index 5a5fc34..ce62abc 100644
--- a/src/ldebug.js
+++ b/src/ldebug.js
@@ -194,10 +194,13 @@ const auxgetinfo = function(L, what, ar, f, ci) {
                 break;
             }
             case 'n': {
-                ar.namewhat = getfuncname(L, ci, ar.name);
-                if (ar.namewhat === null) {
-                    ar.namewhat = [];
+                let r = getfuncname(L, ci);
+                if (r === null) {
+                    ar.namewhat = null;
                     ar.name = null;
+                } else {
+                    ar.namewhat = r.funcname;
+                    ar.name = r.name;
                 }
                 break;
             }
@@ -395,7 +398,7 @@ const funcnamefromcode = function(L, ci) {
 
     let tm = 0;  /* (initial value avoids warnings) */
     let p = ci.func.p;  /* calling function */
-    let pc = ci.pcOff;  /* calling instruction index */
+    let pc = ci.pcOff - 1;  /* calling instruction index */
     let i = p.code[pc];  /* calling instruction */
 
     if (ci.callstatus & lstate.CIST_HOOKED) {
diff --git a/src/lobject.js b/src/lobject.js
index 66a0dcb..618e801 100644
--- a/src/lobject.js
+++ b/src/lobject.js
@@ -306,12 +306,12 @@ const luaO_chunkid = function(source, bufflen) {
             out = RETS.concat(source.slice(1, l - bufflen));
         }
     } else {  /* string; format as [string "source"] */
-        let nli = source.indexOf('\n');  /* find first new line (if any) */
-        let nl = nli ? source.slice(nli) : null;
+        let nli = source.indexOf(char['\n']);  /* find first new line (if any) */
+        let nl = nli > -1 ? source.slice(nli) : null;
         out = PRE;  /* add prefix */
         bufflen -= PRE.length + RETS.length + POS.length + 1;  /* save space for prefix+suffix+'\0' */
         if (l < bufflen && nl === null) {  /* small one-line source? */
-            out = out.conat(source);  /* keep it */
+            out = out.concat(source);  /* keep it */
         } else {
             if (nl !== null) l = nl.length - source.length;  /* stop at first newline */
             if (l > bufflen) l = bufflen;
diff --git a/tests/ldblib.js b/tests/ldblib.js
index 475c031..c95ab9e 100644
--- a/tests/ldblib.js
+++ b/tests/ldblib.js
@@ -89,3 +89,120 @@ test('debug.upvalueid', function (t) {
     );
 
 });
+
+
+test('debug.traceback (with a global)', function (t) {
+    let luaCode = `
+        local trace
+
+        rec = function(n)
+            n = n or 0
+            if n < 10 then
+                rec(n + 1)
+            else
+                trace = debug.traceback()
+            end
+        end
+
+        rec()
+
+        return trace
+    `, L;
+    
+    t.plan(3);
+
+    t.doesNotThrow(function () {
+
+        L = lauxlib.luaL_newstate();
+
+        linit.luaL_openlibs(L);
+
+        luaCode = lua.to_luastring(luaCode);
+        lauxlib.luaL_loadbuffer(L, luaCode, luaCode.length, lua.to_luastring("traceback-test"));
+
+    }, "Lua program loaded without error");
+
+    t.doesNotThrow(function () {
+
+        lapi.lua_call(L, 0, -1);
+
+    }, "Lua program ran without error");
+
+    t.strictEqual(
+        lapi.lua_tojsstring(L, -1),
+`stack traceback:
+\t...[string "traceback-test"]9: in function 'rec'
+\t...[string "traceback-test"]7: in function 'rec'
+\t...[string "traceback-test"]7: in function 'rec'
+\t...[string "traceback-test"]7: in function 'rec'
+\t...[string "traceback-test"]7: in function 'rec'
+\t...[string "traceback-test"]7: in function 'rec'
+\t...[string "traceback-test"]7: in function 'rec'
+\t...[string "traceback-test"]7: in function 'rec'
+\t...[string "traceback-test"]7: in function 'rec'
+\t...[string "traceback-test"]7: in function 'rec'
+\t...[string "traceback-test"]7: in function 'rec'
+\t...[string "traceback-test"]15: in main chunk`,
+        "Correct element(s) on the stack"
+    );
+
+});
+
+
+test('debug.traceback (with a upvalue)', function (t) {
+    let luaCode = `
+        local trace
+        local rec
+
+        rec = function(n)
+            n = n or 0
+            if n < 10 then
+                rec(n + 1)
+            else
+                trace = debug.traceback()
+            end
+        end
+
+        rec()
+
+        return trace
+    `, L;
+    
+    t.plan(3);
+
+    t.doesNotThrow(function () {
+
+        L = lauxlib.luaL_newstate();
+
+        linit.luaL_openlibs(L);
+
+        luaCode = lua.to_luastring(luaCode);
+        lauxlib.luaL_loadbuffer(L, luaCode, luaCode.length, lua.to_luastring("traceback-test"));
+
+    }, "Lua program loaded without error");
+
+    t.doesNotThrow(function () {
+
+        lapi.lua_call(L, 0, -1);
+
+    }, "Lua program ran without error");
+
+    t.strictEqual(
+        lapi.lua_tojsstring(L, -1),
+`stack traceback:
+\t...[string "traceback-test"]10: in upvalue 'rec'
+\t...[string "traceback-test"]8: in upvalue 'rec'
+\t...[string "traceback-test"]8: in upvalue 'rec'
+\t...[string "traceback-test"]8: in upvalue 'rec'
+\t...[string "traceback-test"]8: in upvalue 'rec'
+\t...[string "traceback-test"]8: in upvalue 'rec'
+\t...[string "traceback-test"]8: in upvalue 'rec'
+\t...[string "traceback-test"]8: in upvalue 'rec'
+\t...[string "traceback-test"]8: in upvalue 'rec'
+\t...[string "traceback-test"]8: in upvalue 'rec'
+\t...[string "traceback-test"]8: in local 'rec'
+\t...[string "traceback-test"]16: in main chunk`,
+        "Correct element(s) on the stack"
+    );
+
+});