From b611db6bfa9c12ce35dd4972032fbbd2ad5ba965 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Enrique=20Garc=C3=ADa=20Cota?= <kikito@gmail.com>
Date: Fri, 6 Apr 2018 23:14:00 +0200
Subject: [PATCH] allow using inspect inside __tostring metamethods without
 errors

---
 inspect.lua           | 16 ----------------
 spec/inspect_spec.lua | 37 ++++++++++---------------------------
 2 files changed, 10 insertions(+), 43 deletions(-)

diff --git a/inspect.lua b/inspect.lua
index f4d0e96..e2e3806 100644
--- a/inspect.lua
+++ b/inspect.lua
@@ -124,16 +124,6 @@ local function getNonSequentialKeys(t)
   return keys, keysLength, sequenceLength
 end
 
-local function getToStringResultSafely(t, mt)
-  local __tostring = type(mt) == 'table' and rawget(mt, '__tostring')
-  local str, ok
-  if type(__tostring) == 'function' then
-    ok, str = pcall(__tostring, t)
-    str = ok and str or 'error: ' .. tostring(str)
-  end
-  if type(str) == 'string' and #str > 0 then return str end
-end
-
 local function countTableAppearances(t, tableAppearances)
   tableAppearances = tableAppearances or {}
 
@@ -254,15 +244,9 @@ function Inspector:putTable(t)
 
     local nonSequentialKeys, nonSequentialKeysLength, sequenceLength = getNonSequentialKeys(t)
     local mt                = getmetatable(t)
-    local toStringResult    = getToStringResultSafely(t, mt)
 
     self:puts('{')
     self:down(function()
-      if toStringResult then
-        self:puts(' -- ', escape(toStringResult))
-        if sequenceLength >= 1 then self:tabify() end
-      end
-
       local count = 0
       for i=1, sequenceLength do
         if count > 0 then self:puts(',') end
diff --git a/spec/inspect_spec.lua b/spec/inspect_spec.lua
index 9e61bc1..edea720 100644
--- a/spec/inspect_spec.lua
+++ b/spec/inspect_spec.lua
@@ -363,32 +363,17 @@ describe( 'inspect', function()
         ]]), inspect(bar))
       end)
 
-      it('includes the __tostring metamethod if it exists', function()
-        local foo = { foo = 1, __tostring = function() return 'hello\nworld' end }
-        local bar = setmetatable({a = 1}, foo)
+      it('can be used on the __tostring metamethod of a table without errors', function()
+        local f = function(x) return inspect(x) end
+        local tbl = setmetatable({ x = 1 }, { __tostring = f })
         assert.equals(unindent([[
-          { -- hello\nworld
-            a = 1,
+          {
+            x = 1,
             <metatable> = {
-              __tostring = <function 1>,
-              foo = 1
+              __tostring = <function 1>
             }
           }
-        ]]), inspect(bar))
-      end)
-
-      it('includes an error string if __tostring metamethod throws an error', function()
-        local foo = { foo = 1, __tostring = function() error('hello', 0) end }
-        local bar = setmetatable({a = 1}, foo)
-        assert.equals(unindent([[
-          { -- error: hello
-            a = 1,
-            <metatable> = {
-              __tostring = <function 1>,
-              foo = 1
-            }
-          }
-        ]]), inspect(bar))
+        ]]), tostring(tbl))
       end)
 
       it('does not allow collecting weak tables while they are being inspected', function()
@@ -397,18 +382,16 @@ describe( 'inspect', function()
         local shimMetatable = {
           __mode = 'v',
           __index = function() return {} end,
-          __tostring = function() collectgarbage() return 'shim' end
         }
         local function shim() return setmetatable({}, shimMetatable) end
         local t = shim()
         t.key = shim()
         assert.equals(unindent([[
-          { -- shim
-            key = { -- shim
+          {
+            key = {
               <metatable> = <1>{
                 __index = <function 1>,
-                __mode = "v",
-                __tostring = <function 2>
+                __mode = "v"
               }
             },
             <metatable> = <table 1>