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

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

On Tue, Sep 11, 2018 at 07:15:06PM +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 skipping such requests, since they have no effect anyway.
> 
> Closes #3675
> ---
> https://github.com/tarantool/tarantool/issues/3675
> https://github.com/tarantool/tarantool/tree/sp/gh-3675-tarantoolctl-cat-empty-body
> 
>  extra/dist/tarantoolctl.in | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)

Please add a test.

> 
> diff --git a/extra/dist/tarantoolctl.in b/extra/dist/tarantoolctl.in
> index 3d7ff3ec5..f7b6dd36d 100755
> --- a/extra/dist/tarantoolctl.in
> +++ b/extra/dist/tarantoolctl.in
> @@ -816,11 +816,14 @@ 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 = nil
> +            if record.BODY then
> +                sid = record.BODY.space_id
> +            end

Nit:

  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

I want to see BODY-less requests in the output while this code makes
tarantoolctl-cat ignore them AFAIU.

>                 (not spaces and sid and sid < 512 and not show_system) or
> -               (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
> @@ -857,11 +860,14 @@ 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 = nil
> +            if record.BODY then
> +                sid = record.BODY.space_id
> +            end
>              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
> -               (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