Re: [Tarantool-patches] [PATCH] box.execute should be immutable function

[Nikita Pettik <korablev@tarantool.org>]

On 14 Nov 14:50, Maria wrote:
> Using box.execute method before explicitly
> configuring box automatically invoked box.cfg
> nonetheless. Any further calls to the latter
> caused its reconfiguration which could lead
> to an error when trying to use the method.

Hello. I'm not going to comment patch iteself, just want to leave
a couple of general nits. They are just recommendations.

Feel free to use up to 72 characters while making up commit's body.

I'd fix commit subject:

box.execute should be immutable -> box: make box.execute() immutable despite box.cfg{}
(or sort of).

> Closes #4231
> Issue:
> https://github.com/tarantool/tarantool/issues/4231
> Branch:
> https://github.com/tarantool/tarantool/compare/eljashm/gh-4231-box.execute-immutable-function

Please, put links under --- delimiter so that it will be ignored
by git am.

> ---
>  src/box/lua/load_cfg.lua      |  4 +++-
>  test/box-tap/execute.test.lua | 17 +++++++++++++++++
>  2 files changed, 20 insertions(+), 1 deletion(-)
>  create mode 100755 test/box-tap/execute.test.lua
> 
> diff --git a/src/box/lua/load_cfg.lua b/src/box/lua/load_cfg.lua
> index e7f62cf4e..042edf913 100644
> --- a/src/box/lua/load_cfg.lua
> +++ b/src/box/lua/load_cfg.lua
> @@ -528,7 +528,9 @@ box.cfg = locked(load_cfg)
>  -- metatable.
>  --
>  function box.execute(...)
> -    load_cfg()
> +    if not box.cfg then
> +        load_cfg()
> +    end
>      return box.execute(...)
>  end
>  
> diff --git a/test/box-tap/execute.test.lua b/test/box-tap/execute.test.lua
> new file mode 100755
> index 000000000..301cf4a1c
> --- /dev/null
> +++ b/test/box-tap/execute.test.lua

I'd better name this test ..box-tap/gh-4231-immutable-execute-func.test.lua
It is generally accepted naming way.

> @@ -0,0 +1,17 @@
> +#!/usr/bin/env tarantool
> +
> +local tap = require('tap')
> +local test = tap.test('execute')
> +test:plan(1)

Please, leave comment explaining what exactly is tested here.
For instance:

-- Make sure that box.execute() method does not change after
-- the very first box.cfg{} invokation.
--

> +
> +local box_execute = box.execute
> +box.cfg{}
> +
> +local status, err = pcall(
> +    function() 
> +        box_execute("CREATE TABLE t1 (s1 INTEGER, PRIMARY KEY (s1));") 
> +    end)
> +
> +test:ok(status and err == nil, "box.execute after box.cfg")

I guess this should be error message which is displayed in case
test fails. If so, I'd rather use message like:
"box.execute() is changed after box.cfg{} invokation"