Re: [PATCH 1/2] tarantoolctl: fix cat and play for empty body requests

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

On Fri, Sep 14, 2018 at 05:36:40PM +0300, Serge Petrenko wrote:
> If space.before_replace returns the old tuple, the operation turns into
> no-op, but is still written to WAL as IPROTO_NOP for the sake of
> replication. Such a request doesn't have a body, and tarantoolctl failed
> to parse such requests in `tarantoolctl cat` and `tarantoolctl play`.
> Fix this by checking whether a request has a body. Also skip such
> requests in `play`, since they have no effect.
> 
> Closes #3675
> ---
>  extra/dist/tarantoolctl.in         | 11 +++++++----
>  test/app-tap/tarantoolctl.test.lua | 14 +++++++++++---
>  2 files changed, 18 insertions(+), 7 deletions(-)
> 
> diff --git a/extra/dist/tarantoolctl.in b/extra/dist/tarantoolctl.in
> index 3d7ff3ec5..a6bd15e95 100755
> --- a/extra/dist/tarantoolctl.in
> +++ b/extra/dist/tarantoolctl.in
> @@ -373,6 +373,9 @@ write_lua_table = function(tuple)
>  end
>  
>  local function cat_lua_cb(record)
> +    if record.HEADER.type == 'NOP' then
> +        return
> +    end

IMO better check 'record.BODY.space_id' instead of the type, because the
code below tries to use it.

>      io.stdout:write(('box.space[%d]'):format(record.BODY.space_id))
>      local op = record.HEADER.type:lower()
>      io.stdout:write((':%s('):format(op))
> @@ -816,7 +819,7 @@ local function cat()
>      for id, file in ipairs(positional_arguments) do
>          log.error("Processing file '%s'", file)
>          for lsn, record in xlog.pairs(file) do
> -            local sid = record.BODY.space_id
> +            local sid = record.BODY and record.BODY.space_id
>              local rid = record.HEADER.replica_id
>              if (lsn < from) or
>                 (not spaces and sid and sid < 512 and not show_system) or
> @@ -857,11 +860,11 @@ local function play()
>      for id, file in ipairs(positional_arguments) do
>          log.info(("Processing file '%s'"):format(file))
>          for lsn, record in xlog.pairs(file) do
> -            local sid = record.BODY.space_id
> +            local sid = record.BODY and record.BODY.space_id
>              local rid = record.HEADER.replica_id
> -            if (lsn < from) or
> +            if (lsn < from) or sid == nil or
>                 (not spaces and sid and sid < 512 and not show_system) or

'and sid' is useless after this change

Anyway, strictly speaking this is incorrect, because you won't stop on
a NOP record with lsn >= to, as you're supposed to.

> -               (spaces and (sid == nil or not find_in_list(sid, spaces))) or
> +               (spaces and not find_in_list(sid, spaces)) or
>                 (replicas and not find_in_list(rid, replicas)) then
>                  -- pass this tuple
>              elseif lsn >= to then