Re: [Tarantool-patches] [PATCH v2 1/2] lua: introduce table.equals method

[Serge Petrenko via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

13.08.2021 08:30, Oleg Babin пишет:
> Thanks for your patch.
>
>
> It seems it works in quite strange way:
>
> ```
>
> tarantool> table.equals({a = box.NULL}, {})
> ---
> - true
> ...
>
> tarantool> table.equals({}, {a = box.NULL})
> ---
> - false
> ...
>
> ```
>
>
> I can change arguments order to get different result. Expected false 
> in both cases.
>
> For tap it was considered as buggy behaviour 
> https://github.com/tarantool/tarantool/issues/4125
>
>

====================================

Good catch! Thanks!

Check out the diff:

diff --git a/src/lua/table.lua b/src/lua/table.lua
index 5f35a30f6..3d5e69e97 100644
--- a/src/lua/table.lua
+++ b/src/lua/table.lua
@@ -63,7 +63,7 @@ end
  -- @return true when the two tables are equal (false otherwise).
  local function table_equals(a, b)
      if type(a) ~= 'table' or type(b) ~= 'table' then
-        return a == b
+        return type(a) == type(b) and a == b
      end
      local mt = getmetatable(a)
      if mt and mt.__eq then
diff --git a/test/app-tap/table.test.lua b/test/app-tap/table.test.lua
index a3c9aa123..ec81593f3 100755
--- a/test/app-tap/table.test.lua
+++ b/test/app-tap/table.test.lua
@@ -8,7 +8,7 @@ yaml.cfg{
      encode_invalid_as_nil  = true,
  }
  local test = require('tap').test('table')
-test:plan(38)
+test:plan(40)

  do -- check basic table.copy (deepcopy)
      local example_table = {
@@ -227,6 +227,10 @@ do -- check table.equals
      test:ok(table.equals({}, {}), "table.equals for empty tables")
      test:is(table.equals({}, {1}), false, "table.equals with one empty 
table")
      test:is(table.equals({1}, {}), false, "table.equals with one empty 
table")
+    test:is(table.equals({key = box.NULL}, {key = nil}), false,
+            "table.equals for box.NULL and nil")
+    test:is(table.equals({key = nil}, {key = box.NULL}), false,
+            "table.equals for box.NULL and nil")
      local tbl_a = {
          first = {
              1,

====================================
> On 13.08.2021 02:30, Serge Petrenko via Tarantool-patches wrote:
>> Introduce table.equals for comparing tables.
>> The method respects __eq metamethod, if provided.
>>
>> Needed-for #5894
>> ---
>>

-- 
Serge Petrenko