Re: [PATCH v2] box: allow vinyl_memory set to 0 in config

[Vladimir Davydov <vdavydov.dev@gmail.com>]

On Wed, Jul 04, 2018 at 04:23:48PM +0300, Serge Petrenko wrote:
> Sorry, forgot to post diff.

All extra information that you want to get to the reviewer should go
after --- (where you put branch and change log). This way it will be
ignored by `git am` (we don't use it now, but people in other projects
do and we might want to start using it instead of `git merge` one day).

> 
> In 1.9 it was possible to have a vinylless configuration with
> vinyl_memory=0, allow to do this in 1.10 by adjusting sanity
> checks for vinyl_memory and memtx_memory. Now banning only
> negative values.
> memtx_memory check was changed for consistency, trying to
> set memtx_memory to 0 fails anyways.
> Also added a test to check that vinyl_memory can actually
> be set to 0.
> 
> Closes: #3468
> ---
> https://github.com/tarantool/tarantool/tree/sergepetrenko/gh-3468-allow-0-vinyl-memory
> https://github.com/tarantool/tarantool/issues/3468
> 
> Changes in v2:
> - added a test case to check vinyl_memory=0 is legal.

> diff --git a/test/box-tap/cfg.test.lua b/test/box-tap/cfg.test.lua
> index b93a21f35..764fade93 100755
> --- a/test/box-tap/cfg.test.lua
> +++ b/test/box-tap/cfg.test.lua
> @@ -6,7 +6,7 @@ local socket = require('socket')
>  local fio = require('fio')
>  local uuid = require('uuid')
>  local msgpack = require('msgpack')
> -test:plan(91)
> +test:plan(93)
>  
>  --------------------------------------------------------------------------------
>  -- Invalid values
> @@ -82,9 +82,15 @@ os.execute("rm -rf vinyl")
>  box.cfg{
>      log="tarantool.log",
>      memtx_memory=104857600,
> +    vinyl_memory=0,
>      wal_mode = "", -- "" means default value
>  }
>  
> +status, result = pcall(testfun)
> +test:ok(status  and result == "table", "allow vinyl_memory set to 0 in box.cfg")
> +test:is(box.cfg.vinyl_memory, 0, "vinyl_memory actually set to 0")
> +
> +box.cfg{vinyl_memory=128 * 1024 * 1024}
>  -- gh-678: vinyl engine creates vinyl dir with empty 'snapshot' file
>  test:isnil(io.open("vinyl", 'r'), 'vinyl_dir is not auto-created')

That's not exactly what I meant. There's an easier way to test initial
box configuration:

  code = [[ box.cfg{ vinyl_memory=0 } ]]
  test:is(run_script(code), 0, 'vinyl_memory is 0')

(there are plenty of similar test cases in box-tap/cfg.test.lua)

Also, when you add a test case, please write a brief description with a
reference to the github ticket you're fixing, e.g.

(also from box-tap/cfg.test.lua)
> -- gh-2664: vinyl_dir is checked on the first use
> code = [[ box.cfg{ vinyl_dir='invalid' } ]]
> test:is(run_script(code), 0, 'vinyl_dir is invalid')