From 3e439ed653093e6e124a4997f64053164f1043b8 Mon Sep 17 00:00:00 2001
From: daurnimator <quae@daurnimator.com>
Date: Tue, 9 May 2017 17:02:31 +1000
Subject: src/lapi.js: lobject.luaO_str2num returns false if string is not a
 number

---
 src/lapi.js       | 10 +++++++---
 tests/lbaselib.js | 15 ++++++++++++---
 2 files changed, 19 insertions(+), 6 deletions(-)

diff --git a/src/lapi.js b/src/lapi.js
index e035aca..307d4e3 100644
--- a/src/lapi.js
+++ b/src/lapi.js
@@ -731,9 +731,13 @@ const lua_compare = function(L, index1, index2, op) {
 };
 
 const lua_stringtonumber = function(L, s) {
-    L.stack[L.top++] = lobject.luaO_str2num(s);
-    assert(L.top <= L.ci.top, "stack overflow");
-    return s.length;
+    let tv = lobject.luaO_str2num(s);
+    if (tv) {
+        L.stack[L.top++] = tv;
+        assert(L.top <= L.ci.top, "stack overflow");
+        return s.length;
+    }
+    return 0;
 };
 
 const lua_tointegerx = function(L, idx) {
diff --git a/tests/lbaselib.js b/tests/lbaselib.js
index 0a77e5b..ca83467 100644
--- a/tests/lbaselib.js
+++ b/tests/lbaselib.js
@@ -438,10 +438,14 @@ test('select', function (t) {
 
 test('tonumber', function (t) {
     let luaCode = `
-        return tonumber('123'), tonumber('12.3'), tonumber('az', 36), tonumber('10', 2)
+        return tonumber('foo'),
+            tonumber('123'),
+            tonumber('12.3'),
+            tonumber('az', 36),
+            tonumber('10', 2)
     `, L;
-    
-    t.plan(5);
+
+    t.plan(6);
 
     t.doesNotThrow(function () {
 
@@ -457,6 +461,11 @@ test('tonumber', function (t) {
 
     }, "JS Lua program ran without error");
 
+    t.ok(
+        lua.lua_isnil(L, -5),
+        "Correct element(s) on the stack"
+    );
+
     t.strictEqual(
         lua.lua_tonumber(L, -4),
         123,
-- 
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