Re: [Tarantool-patches] [PATCH v5 07/10] Fix luacheck warnings in src/box/lua/

[Sergey Bronnikov <sergeyb@tarantool.org>]

Accidentally this patch became splitted with previous patch (patch 06)
after rebase to master. I have squashed both in a branch.

On 12:50 Tue 12 May , sergeyb@tarantool.org wrote:
> From: Sergey Bronnikov <sergeyb@tarantool.org>
> 
> Closes #4681
> 
> Reviewed-by: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
> Co-authored-by: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
> ---
>  src/box/lua/console.lua         |  6 ++--
>  src/box/lua/feedback_daemon.lua |  2 +-
>  src/box/lua/key_def.lua         |  2 +-
>  src/box/lua/load_cfg.lua        | 31 ++++++++++---------
>  src/box/lua/net_box.lua         | 53 +++++++++++++--------------------
>  src/box/lua/schema.lua          | 50 +++++++++++++++----------------
>  src/box/lua/tuple.lua           |  8 ++---
>  src/box/lua/upgrade.lua         | 19 ++++++------
>  8 files changed, 78 insertions(+), 93 deletions(-)
> 
> diff --git a/src/box/lua/console.lua b/src/box/lua/console.lua
> index 2add9a79d..5fd8b5e4e 100644
> --- a/src/box/lua/console.lua
> +++ b/src/box/lua/console.lua
> @@ -465,7 +465,7 @@ local text_connection_mt = {
>                  -- Make sure it is exactly "\set output" command.
>                  if operators[items[1]] == set_param and
>                      param_handlers[items[2]] == set_output then
> -                    local err, fmt, opts = parse_output(items[3])
> +                    local err, fmt = parse_output(items[3])
>                      if not err then
>                          self.fmt = fmt
>                          self.eos = output_eos[fmt]
> @@ -489,7 +489,7 @@ local text_connection_mt = {
>                      break
>                  end
>                  if fmt == "yaml" then
> -                    local handle, prefix = yaml.decode(rc, {tag_only = true})
> +                    local handle = yaml.decode(rc, {tag_only = true})
>                      if not handle then
>                          -- Can not fail - tags are encoded with no
>                          -- user participation and are correct always.
> @@ -869,7 +869,7 @@ local function listen(uri)
>          host = u.host
>          port = u.service or 3313
>      end
> -    local s, addr = socket.tcp_server(host, port, { handler = client_handler,
> +    local s = socket.tcp_server(host, port, { handler = client_handler,
>          name = 'console'})
>      if not s then
>          error(string.format('failed to create server %s:%s: %s',
> diff --git a/src/box/lua/feedback_daemon.lua b/src/box/lua/feedback_daemon.lua
> index 95130d696..db74f558b 100644
> --- a/src/box/lua/feedback_daemon.lua
> +++ b/src/box/lua/feedback_daemon.lua
> @@ -61,7 +61,7 @@ local function guard_loop(self)
>              self.fiber = fiber.create(feedback_loop, self)
>              log.verbose("%s restarted", PREFIX)
>          end
> -        local st, err = pcall(fiber.sleep, self.interval)
> +        local st = pcall(fiber.sleep, self.interval)
>          if not st then
>              -- fiber was cancelled
>              break
> diff --git a/src/box/lua/key_def.lua b/src/box/lua/key_def.lua
> index 586005709..a1b61441e 100644
> --- a/src/box/lua/key_def.lua
> +++ b/src/box/lua/key_def.lua
> @@ -15,5 +15,5 @@ ffi.metatype(key_def_t, {
>      __index = function(self, key)
>          return methods[key]
>      end,
> -    __tostring = function(key_def) return "<struct key_def &>" end,
> +    __tostring = function() return "<struct key_def &>" end,
>  })
> diff --git a/src/box/lua/load_cfg.lua b/src/box/lua/load_cfg.lua
> index 5d818addf..bb00e71ee 100644
> --- a/src/box/lua/load_cfg.lua
> +++ b/src/box/lua/load_cfg.lua
> @@ -36,7 +36,7 @@ local ifdef_feedback_set_params =
>      private.feedback_daemon.set_feedback_params or nil
>  
>  -- all available options
> -local default_cfg = {
> +local default_config = {
>      listen              = nil,
>      memtx_memory        = 256 * 1024 *1024,
>      strip_core          = true,
> @@ -101,7 +101,7 @@ local default_cfg = {
>  
>  -- types of available options
>  -- could be comma separated lua types or 'any' if any type is allowed
> -local template_cfg = {
> +local template_config = {
>      listen              = 'string, number',
>      memtx_memory        = 'number',
>      strip_core          = 'boolean',
> @@ -184,7 +184,7 @@ local function normalize_uri_list(port_list)
>  end
>  
>  -- options that require special handling
> -local modify_cfg = {
> +local modify_config = {
>      listen             = normalize_uri,
>      replication        = normalize_uri_list,
>  }
> @@ -272,8 +272,8 @@ local dynamic_cfg = {
>      sql_cache_size          = private.cfg_set_sql_cache_size,
>  }
>  
> -ifdef_feedback = nil
> -ifdef_feedback_set_params = nil
> +ifdef_feedback = nil -- luacheck: ignore
> +ifdef_feedback_set_params = nil -- luacheck: ignore
>  
>  --
>  -- For some options it is important in which order they are set.
> @@ -352,7 +352,7 @@ end
>  -- value of the old option, value of the new if present. It
>  -- returns two values - value to replace the old option and to
>  -- replace the new one.
> -local translate_cfg = {
> +local translate_config = {
>      snapshot_count = {'checkpoint_count'},
>      snapshot_period = {'checkpoint_interval'},
>      slab_alloc_arena = {'memtx_memory', function(old)
> @@ -431,7 +431,7 @@ local function prepare_cfg(cfg, default_cfg, template_cfg, modify_cfg, prefix)
>          elseif v == "" or v == nil then
>              -- "" and NULL = ffi.cast('void *', 0) set option to default value
>              v = default_cfg[k]
> -        elseif template_cfg[k] == 'any' then
> +        elseif template_cfg[k] == 'any' then -- luacheck: ignore
>              -- any type is ok
>          elseif type(template_cfg[k]) == 'table' then
>              if type(v) ~= 'table' then
> @@ -447,7 +447,6 @@ local function prepare_cfg(cfg, default_cfg, template_cfg, modify_cfg, prefix)
>          else
>              local good_types = string.gsub(template_cfg[k], ' ', '');
>              if (string.find(',' .. good_types .. ',', ',' .. type(v) .. ',') == nil) then
> -                good_types = string.gsub(good_types, ',', ', ');
>                  box.error(box.error.CFG, readable_name, "should be one of types "..
>                      template_cfg[k])
>              end
> @@ -490,8 +489,8 @@ local function compare_cfg(cfg1, cfg2)
>  end
>  
>  local function reload_cfg(oldcfg, cfg)
> -    cfg = upgrade_cfg(cfg, translate_cfg)
> -    local newcfg = prepare_cfg(cfg, default_cfg, template_cfg, modify_cfg)
> +    cfg = upgrade_cfg(cfg, translate_config)
> +    local newcfg = prepare_cfg(cfg, default_config, template_config, modify_config)
>      local ordered_cfg = {}
>      -- iterate over original table because prepare_cfg() may store NILs
>      for key, val in pairs(cfg) do
> @@ -544,16 +543,16 @@ for k, v in pairs(box) do
>  end
>  
>  setmetatable(box, {
> -    __index = function(table, index)
> +    __index = function()
>          error(debug.traceback("Please call box.cfg{} first"))
>          error("Please call box.cfg{} first")
>       end
>  })
>  
>  local function load_cfg(cfg)
> -    cfg = upgrade_cfg(cfg, translate_cfg)
> -    cfg = prepare_cfg(cfg, default_cfg, template_cfg, modify_cfg)
> -    apply_default_cfg(cfg, default_cfg);
> +    cfg = upgrade_cfg(cfg, translate_config)
> +    cfg = prepare_cfg(cfg, default_config, template_config, modify_config)
> +    apply_default_cfg(cfg, default_config);
>      -- Save new box.cfg
>      box.cfg = cfg
>      if not pcall(private.cfg_check)  then
> @@ -568,7 +567,7 @@ local function load_cfg(cfg)
>      box_configured = nil
>      box.cfg = setmetatable(cfg,
>          {
> -            __newindex = function(table, index)
> +            __newindex = function()
>                  error('Attempt to modify a read-only table')
>              end,
>              __call = locked(reload_cfg),
> @@ -580,7 +579,7 @@ local function load_cfg(cfg)
>              if not dynamic_cfg_skip_at_load[key] then
>                  fun()
>              end
> -            if not compare_cfg(val, default_cfg[key]) then
> +            if not compare_cfg(val, default_config[key]) then
>                  if log_cfg_option[key] ~= nil then
>                      val = log_cfg_option[key](val)
>                  end
> diff --git a/src/box/lua/net_box.lua b/src/box/lua/net_box.lua
> index 9560bfdd4..3f2a9df81 100644
> --- a/src/box/lua/net_box.lua
> +++ b/src/box/lua/net_box.lua
> @@ -39,10 +39,6 @@ local IPROTO_STATUS_KEY    = 0x00
>  local IPROTO_ERRNO_MASK    = 0x7FFF
>  local IPROTO_SYNC_KEY      = 0x01
>  local IPROTO_SCHEMA_VERSION_KEY = 0x05
> -local IPROTO_METADATA_KEY = 0x32
> -local IPROTO_SQL_INFO_KEY = 0x42
> -local SQL_INFO_ROW_COUNT_KEY = 0
> -local IPROTO_FIELD_NAME_KEY = 0
>  local IPROTO_DATA_KEY      = 0x30
>  local IPROTO_ERROR_24      = 0x31
>  local IPROTO_ERROR         = 0x52
> @@ -68,18 +64,18 @@ error_unref(struct error *e);
>  -- utility tables
>  local is_final_state         = {closed = 1, error = 1}
>  
> -local function decode_nil(raw_data, raw_data_end)
> +local function decode_nil(raw_data, raw_data_end) -- luacheck: no unused args
>      return nil, raw_data_end
>  end
>  local function decode_data(raw_data)
>      local response, raw_end = decode(raw_data)
>      return response[IPROTO_DATA_KEY], raw_end
>  end
> -local function decode_tuple(raw_data, raw_data_end, format)
> +local function decode_tuple(raw_data, raw_data_end, format) -- luacheck: no unused args
>      local response, raw_end = internal.decode_select(raw_data, nil, format)
>      return response[1], raw_end
>  end
> -local function decode_get(raw_data, raw_data_end, format)
> +local function decode_get(raw_data, raw_data_end, format) -- luacheck: no unused args
>      local body, raw_end = internal.decode_select(raw_data, nil, format)
>      if body[2] then
>          return nil, raw_end, box.error.MORE_THAN_ONE_TUPLE
> @@ -122,7 +118,7 @@ local method_encoder = {
>      max     = internal.encode_select,
>      count   = internal.encode_call,
>      -- inject raw data into connection, used by console and tests
> -    inject = function(buf, id, bytes)
> +    inject = function(buf, id, bytes) -- luacheck: no unused args
>          local ptr = buf:reserve(#bytes)
>          ffi.copy(ptr, bytes, #bytes)
>          buf.wpos = ptr + #bytes
> @@ -187,7 +183,7 @@ local function next_id(id) return band(id + 1, 0x7FFFFFFF) end
>  -- @retval two non-nils A connected socket and a decoded greeting.
>  --
>  local function establish_connection(host, port, timeout)
> -    local timeout = timeout or DEFAULT_CONNECT_TIMEOUT
> +    timeout = timeout or DEFAULT_CONNECT_TIMEOUT
>      local begin = fiber.clock()
>      local s = socket.tcp_connect(host, port, timeout)
>      if not s then
> @@ -212,7 +208,7 @@ end
>  -- Default action on push during a synchronous request -
>  -- ignore.
>  --
> -local function on_push_sync_default(...) end
> +local function on_push_sync_default() end
>  
>  --
>  -- Basically, *transport* is a TCP connection speaking one of
> @@ -253,7 +249,7 @@ local function on_push_sync_default(...) end
>  --
>  -- The following events are delivered, with arguments:
>  --
> ---  'state_changed', state, errno, error
> +--  'state_changed', state, errno
>  --  'handshake', greeting -> nil (accept) / errno, error (reject)
>  --  'will_fetch_schema'   -> true (approve) / false (skip fetch)
>  --  'did_fetch_schema', schema_version, spaces, indices
> @@ -449,7 +445,7 @@ local function create_transport(host, port, user, password, callback,
>          state = new_state
>          last_errno = new_errno
>          last_error = new_error
> -        callback('state_changed', new_state, new_errno, new_error)
> +        callback('state_changed', new_state, new_error)
>          state_cond:broadcast()
>          if state == 'error' or state == 'error_reconnect' or
>             state == 'closed' then
> @@ -598,7 +594,7 @@ local function create_transport(host, port, user, password, callback,
>              -- Handle errors
>              requests[id] = nil
>              request.id = nil
> -            local map_len, key, skip
> +            local map_len, key
>              map_len, body_rpos = decode_map_header(body_rpos, body_len)
>              -- Reserve for 2 keys and 2 array indexes. Because no
>              -- any guarantees how Lua will decide to save the
> @@ -610,7 +606,7 @@ local function create_transport(host, port, user, password, callback,
>                  if rdec then
>                      body[key], body_rpos = rdec(body_rpos)
>                  else
> -                    skip, body_rpos = decode(body_rpos)
> +                    _, body_rpos = decode(body_rpos)
>                  end
>              end
>              assert(body_end == body_rpos, "invalid xrow length")
> @@ -689,7 +685,7 @@ local function create_transport(host, port, user, password, callback,
>  
>      local function send_and_recv_iproto(timeout)
>          local data_len = recv_buf.wpos - recv_buf.rpos
> -        local required = 0
> +        local required
>          if data_len < 5 then
>              required = 5
>          else
> @@ -753,7 +749,8 @@ local function create_transport(host, port, user, password, callback,
>                       "please use require('console').connect() instead")
>              local setup_delimiter = 'require("console").delimiter("$EOF$")\n'
>              method_encoder.inject(send_buf, nil, setup_delimiter)
> -            local err, response = send_and_recv_console()
> +            local response
> +            err, response = send_and_recv_console()
>              if err then
>                  return error_sm(err, response)
>              elseif response ~= '---\n...\n' then
> @@ -771,7 +768,6 @@ local function create_transport(host, port, user, password, callback,
>      end
>  
>      console_sm = function(rid)
> -        local delim = '\n...\n'
>          local err, response = send_and_recv_console()
>          if err then
>              return error_sm(err, response)
> @@ -795,13 +791,12 @@ local function create_transport(host, port, user, password, callback,
>              return iproto_schema_sm()
>          end
>          encode_auth(send_buf, new_request_id(), user, password, salt)
> -        local err, hdr, body_rpos, body_end = send_and_recv_iproto()
> +        local err, hdr, body_rpos = send_and_recv_iproto()
>          if err then
>              return error_sm(err, hdr)
>          end
>          if hdr[IPROTO_STATUS_KEY] ~= 0 then
> -            local body
> -            body, body_end = decode(body_rpos)
> +            local body, _ = decode(body_rpos)
>              return error_sm(E_NO_CONNECTION, body[IPROTO_ERROR_24])
>          end
>          set_state('fetch_schema')
> @@ -852,8 +847,7 @@ local function create_transport(host, port, user, password, callback,
>                          peer_has_vcollation = false
>                          goto continue
>                      end
> -                    local body
> -                    body, body_end = decode(body_rpos)
> +                    local body, _ = decode(body_rpos)
>                      return error_sm(E_NO_CONNECTION, body[IPROTO_ERROR_24])
>                  end
>                  if schema_version == nil then
> @@ -862,8 +856,7 @@ local function create_transport(host, port, user, password, callback,
>                      -- schema changed while fetching schema; restart loader
>                      return iproto_schema_sm()
>                  end
> -                local body
> -                body, body_end = decode(body_rpos)
> +                local body = decode(body_rpos)
>                  response[id] = body[IPROTO_DATA_KEY]
>              end
>              ::continue::
> @@ -880,14 +873,11 @@ local function create_transport(host, port, user, password, callback,
>          local err, hdr, body_rpos, body_end = send_and_recv_iproto()
>          if err then return error_sm(err, hdr) end
>          dispatch_response_iproto(hdr, body_rpos, body_end)
> -        local status = hdr[IPROTO_STATUS_KEY]
>          local response_schema_version = hdr[IPROTO_SCHEMA_VERSION_KEY]
>          if response_schema_version > 0 and
>             response_schema_version ~= schema_version then
>              -- schema_version has been changed - start to load a new version.
>              -- Sic: self.schema_version will be updated only after reload.
> -            local body
> -            body, body_end = decode(body_rpos)
>              set_state('fetch_schema')
>              return iproto_schema_sm(schema_version)
>          end
> @@ -1004,7 +994,7 @@ local function new_sm(host, port, opts, connection, greeting)
>      local remote = {host = host, port = port, opts = opts, state = 'initial'}
>      local function callback(what, ...)
>          if what == 'state_changed' then
> -            local state, errno, err = ...
> +            local state, err = ...
>              local was_connected = remote._is_connected
>              if state == 'active' then
>                  if not was_connected then
> @@ -1275,7 +1265,7 @@ function remote_methods:execute(query, parameters, sql_opts, netbox_opts)
>                           sql_opts or {})
>  end
>  
> -function remote_methods:prepare(query, parameters, sql_opts, netbox_opts)
> +function remote_methods:prepare(query, parameters, sql_opts, netbox_opts) -- luacheck: no unused args
>      check_remote_arg(self, "prepare")
>      if type(query) ~= "string" then
>          box.error(box.error.SQL_PREPARE, "expected string as SQL statement")
> @@ -1640,7 +1630,7 @@ this_module.self = {
>      timeout = function(self) return self end,
>      wait_connected = function(self) return true end,
>      is_connected = function(self) return true end,
> -    call = function(_box, proc_name, args, opts)
> +    call = function(_box, proc_name, args)
>          check_remote_arg(_box, 'call')
>          check_call_args(args)
>          args = args or {}
> @@ -1651,14 +1641,13 @@ this_module.self = {
>              rollback()
>              return box.error() -- re-throw
>          end
> -        local result
>          if obj ~= nil then
>              return handle_eval_result(pcall(proc, obj, unpack(args)))
>          else
>              return handle_eval_result(pcall(proc, unpack(args)))
>          end
>      end,
> -    eval = function(_box, expr, args, opts)
> +    eval = function(_box, expr, args)
>          check_remote_arg(_box, 'eval')
>          check_eval_args(args)
>          args = args or {}
> diff --git a/src/box/lua/schema.lua b/src/box/lua/schema.lua
> index cdfbb65f7..811cbbfef 100644
> --- a/src/box/lua/schema.lua
> +++ b/src/box/lua/schema.lua
> @@ -2,7 +2,6 @@
>  --
>  local ffi = require('ffi')
>  local msgpack = require('msgpack')
> -local msgpackffi = require('msgpackffi')
>  local fun = require('fun')
>  local log = require('log')
>  local buffer = require('buffer')
> @@ -212,7 +211,7 @@ local function revoke_object_privs(object_type, object_id)
>      local _vpriv = box.space[box.schema.VPRIV_ID]
>      local _priv = box.space[box.schema.PRIV_ID]
>      local privs = _vpriv.index.object:select{object_type, object_id}
> -    for k, tuple in pairs(privs) do
> +    for _, tuple in pairs(privs) do
>          local uid = tuple.grantee
>          _priv:delete{uid, object_type, object_id}
>      end
> @@ -262,7 +261,7 @@ local function check_param_table(table, template)
>          if template[k] == nil then
>              box.error(box.error.ILLEGAL_PARAMS,
>                        "unexpected option '" .. k .. "'")
> -        elseif template[k] == 'any' then
> +        elseif template[k] == 'any' then -- luacheck: ignore
>              -- any type is ok
>          elseif (string.find(template[k], ',') == nil) then
>              -- one type
> @@ -276,7 +275,6 @@ local function check_param_table(table, template)
>              local haystack = ',' .. good_types .. ','
>              local needle = ',' .. param_type(v) .. ','
>              if (string.find(haystack, needle) == nil) then
> -                good_types = string.gsub(good_types, ',', ', ')
>                  box.error(box.error.ILLEGAL_PARAMS,
>                            "options parameter '" .. k ..
>                            "' should be one of types: " .. template[k])
> @@ -584,9 +582,9 @@ end
>  --
>  local function format_field_resolve(format, path, what)
>      assert(type(path) == 'number' or type(path) == 'string')
> -    local idx = nil
> +    local idx
>      local relative_path = nil
> -    local field_name = nil
> +    local field_name
>      -- Path doesn't require resolve.
>      if type(path) == 'number' then
>          idx = path
> @@ -846,7 +844,7 @@ local function space_sequence_alter_prepare(format, parts, options,
>              if id == nil then
>                  box.error(box.error.NO_SUCH_SEQUENCE, new_sequence.id)
>              end
> -            local tuple = _space_sequence.index.sequence:select(id)[1]
> +            tuple = _space_sequence.index.sequence:select(id)[1]
>              if tuple ~= nil and tuple.is_generated then
>                  box.error(box.error.ALTER_SPACE, space_name,
>                            "can not attach generated sequence")
> @@ -1146,7 +1144,7 @@ box.schema.index.alter = function(space_id, index_id, options)
>          local can_update_field = {id = true, name = true, type = true }
>          local can_update = true
>          local cant_update_fields = ''
> -        for k,v in pairs(options) do
> +        for k, _ in pairs(options) do
>              if not can_update_field[k] then
>                  can_update = false
>                  cant_update_fields = cant_update_fields .. ' ' .. k
> @@ -1190,7 +1188,7 @@ box.schema.index.alter = function(space_id, index_id, options)
>      if options.type == nil then
>          options.type = tuple.type
>      end
> -    for k, t in pairs(index_options) do
> +    for k, _ in pairs(index_options) do
>          if options[k] ~= nil then
>              index_opts[k] = options[k]
>          end
> @@ -1233,12 +1231,12 @@ end
>  
>  local iterator_t = ffi.typeof('struct iterator')
>  ffi.metatype(iterator_t, {
> -    __tostring = function(iterator)
> +    __tostring = function()
>          return "<iterator state>"
>      end;
>  })
>  
> -local iterator_gen = function(param, state)
> +local iterator_gen = function(param, state) -- luacheck: no unused args
>      --[[
>          index:pairs() mostly conforms to the Lua for-in loop conventions and
>          tries to follow the best practices of Lua community.
> @@ -1272,7 +1270,7 @@ local iterator_gen = function(param, state)
>      end
>  end
>  
> -local iterator_gen_luac = function(param, state)
> +local iterator_gen_luac = function(param, state) -- luacheck: no unused args
>      local tuple = internal.iterator_next(state)
>      if tuple ~= nil then
>          return state, tuple -- new state, value
> @@ -1500,7 +1498,8 @@ end
>  
>  base_index_mt.get_ffi = function(index, key)
>      check_index_arg(index, 'get')
> -    local key, key_end = tuple_encode(key)
> +    local key_end
> +    key, key_end = tuple_encode(key)
>      if builtin.box_index_get(index.space_id, index.id,
>                               key, key_end, ptuple) ~= 0 then
>          return box.error() -- error
> @@ -1533,7 +1532,8 @@ end
>  
>  base_index_mt.select_ffi = function(index, key, opts)
>      check_index_arg(index, 'select')
> -    local key, key_end = tuple_encode(key)
> +    local key_end
> +    key, key_end = tuple_encode(key)
>      local iterator, offset, limit = check_select_opts(opts, key + 1 >= key_end)
>  
>      local port = ffi.cast('struct port *', port_c)
> @@ -1555,7 +1555,7 @@ end
>  
>  base_index_mt.select_luac = function(index, key, opts)
>      check_index_arg(index, 'select')
> -    local key = keify(key)
> +    key = keify(key)
>      local iterator, offset, limit = check_select_opts(opts, #key == 0)
>      return internal.select(index.space_id, index.id, iterator,
>          offset, limit, key)
> @@ -1775,9 +1775,9 @@ local function wrap_schema_object_mt(name)
>          __pairs = global_mt.__pairs
>      }
>      local mt_mt = {}
> -    mt_mt.__newindex = function(t, k, v)
> +    mt_mt.__newindex = function(self, k, v)
>          mt_mt.__newindex = nil
> -        mt.__index = function(t, k)
> +        mt.__index = function(self, k)
>              return mt[k] or box.schema[name][k]
>          end
>          rawset(mt, k, v)
> @@ -2486,24 +2486,24 @@ local function revoke(uid, name, privilege, object_type, object_name, options)
>      end
>  end
>  
> -local function drop(uid, opts)
> +local function drop(uid)
>      -- recursive delete of user data
>      local _vpriv = box.space[box.schema.VPRIV_ID]
>      local spaces = box.space[box.schema.VSPACE_ID].index.owner:select{uid}
> -    for k, tuple in pairs(spaces) do
> +    for _, tuple in pairs(spaces) do
>          box.space[tuple.id]:drop()
>      end
>      local funcs = box.space[box.schema.VFUNC_ID].index.owner:select{uid}
> -    for k, tuple in pairs(funcs) do
> +    for _, tuple in pairs(funcs) do
>          box.schema.func.drop(tuple.id)
>      end
>      -- if this is a role, revoke this role from whoever it was granted to
>      local grants = _vpriv.index.object:select{'role', uid}
> -    for k, tuple in pairs(grants) do
> +    for _, tuple in pairs(grants) do
>          revoke(tuple.grantee, tuple.grantee, uid)
>      end
>      local sequences = box.space[box.schema.VSEQUENCE_ID].index.owner:select{uid}
> -    for k, tuple in pairs(sequences) do
> +    for _, tuple in pairs(sequences) do
>          box.schema.sequence.drop(tuple.id)
>      end
>      -- xxx: hack, we have to revoke session and usage privileges
> @@ -2515,7 +2515,7 @@ local function drop(uid, opts)
>      end
>      local privs = _vpriv.index.primary:select{uid}
>  
> -    for k, tuple in pairs(privs) do
> +    for _, tuple in pairs(privs) do
>          -- we need an additional box.session.su() here, because of
>          -- unnecessary check for privilege PRIV_REVOKE in priv_def_check()
>          box.session.su("admin", revoke, uid, uid, tuple.privilege,
> @@ -2565,7 +2565,7 @@ box.schema.user.drop = function(name, opts)
>              box.error(box.error.DROP_USER, name,
>                        "the user is active in the current session")
>          end
> -        return drop(uid, opts)
> +        return drop(uid)
>      end
>      if not opts.if_exists then
>          box.error(box.error.NO_SUCH_USER, name)
> @@ -2681,7 +2681,7 @@ box.once = function(key, func, ...)
>          box.error(box.error.ILLEGAL_PARAMS, "Usage: box.once(key, func, ...)")
>      end
>  
> -    local key = "once"..key
> +    key = "once"..key
>      if box.space._schema:get{key} ~= nil then
>          return
>      end
> diff --git a/src/box/lua/tuple.lua b/src/box/lua/tuple.lua
> index f97aa1579..1b958425f 100644
> --- a/src/box/lua/tuple.lua
> +++ b/src/box/lua/tuple.lua
> @@ -1,7 +1,6 @@
>  -- tuple.lua (internal file)
>  
>  local ffi = require('ffi')
> -local yaml = require('yaml')
>  local msgpackffi = require('msgpackffi')
>  local fun = require('fun')
>  local buffer = require('buffer')
> @@ -81,7 +80,6 @@ local tuple_encode = function(obj)
>          encode_r(tmpbuf, obj, 1)
>      elseif type(obj) == "table" then
>          encode_array(tmpbuf, #obj)
> -        local i
>          for i = 1, #obj, 1 do
>              encode_r(tmpbuf, obj[i], 1)
>          end
> @@ -232,7 +230,7 @@ local function tuple_update(tuple, expr)
>          error("Usage: tuple:update({ { op, field, arg}+ })")
>      end
>      local pexpr, pexpr_end = tuple_encode(expr)
> -    local tuple = builtin.box_tuple_update(tuple, pexpr, pexpr_end)
> +    tuple = builtin.box_tuple_update(tuple, pexpr, pexpr_end)
>      if tuple == nil then
>          return box.error()
>      end
> @@ -245,7 +243,7 @@ local function tuple_upsert(tuple, expr)
>          error("Usage: tuple:upsert({ { op, field, arg}+ })")
>      end
>      local pexpr, pexpr_end = tuple_encode(expr)
> -    local tuple = builtin.box_tuple_upsert(tuple, pexpr, pexpr_end)
> +    tuple = builtin.box_tuple_upsert(tuple, pexpr, pexpr_end)
>      if tuple == nil then
>          return box.error()
>      end
> @@ -339,7 +337,7 @@ ffi.metatype(tuple_t, {
>  
>  ffi.metatype(tuple_iterator_t, {
>      __call = tuple_iterator_next;
> -    __tostring = function(it) return "<tuple iterator>" end;
> +    __tostring = function() return "<tuple iterator>" end;
>  })
>  
>  -- Free methods, which are not needed anymore.
> diff --git a/src/box/lua/upgrade.lua b/src/box/lua/upgrade.lua
> index 075cc236e..208b53f15 100644
> --- a/src/box/lua/upgrade.lua
> +++ b/src/box/lua/upgrade.lua
> @@ -52,10 +52,9 @@ end
>  local function truncate(space)
>      local pk = space.index[0]
>      while pk:len() > 0 do
> -        local state, t
> -        for state, t in pk:pairs() do
> +        for _, t in pk:pairs() do
>              local key = {}
> -            for _k2, parts in ipairs(pk.parts) do
> +            for _, parts in ipairs(pk.parts) do
>                  table.insert(key, t[parts.fieldno])
>              end
>              space:delete(key)
> @@ -173,7 +172,7 @@ local function initial_1_7_5()
>      format[5] = {name='field_count', type='unsigned'}
>      format[6] = {name='flags', type='map'}
>      format[7] = {name='format', type='array'}
> -    local def = _space:insert{_space.id, ADMIN, '_space', 'memtx', 0, MAP, format}
> +    _space:insert{_space.id, ADMIN, '_space', 'memtx', 0, MAP, format}
>      -- space name is unique
>      log.info("create index primary on _space")
>      _index:insert{_space.id, 0, 'primary', 'tree', { unique = true }, {{0, 'unsigned'}}}
> @@ -194,7 +193,7 @@ local function initial_1_7_5()
>      format[4] = {name = 'type', type = 'string'}
>      format[5] = {name = 'opts', type = 'map'}
>      format[6] = {name = 'parts', type = 'array'}
> -    def = _space:insert{_index.id, ADMIN, '_index', 'memtx', 0, MAP, format}
> +    _space:insert{_index.id, ADMIN, '_index', 'memtx', 0, MAP, format}
>      -- index name is unique within a space
>      log.info("create index primary on _index")
>      _index:insert{_index.id, 0, 'primary', 'tree', {unique = true}, {{0, 'unsigned'}, {1, 'unsigned'}}}
> @@ -211,7 +210,7 @@ local function initial_1_7_5()
>      format[2] = {name='owner', type='unsigned'}
>      format[3] = {name='name', type='string'}
>      format[4] = {name='setuid', type='unsigned'}
> -    def = _space:insert{_func.id, ADMIN, '_func', 'memtx', 0, MAP, format}
> +    _space:insert{_func.id, ADMIN, '_func', 'memtx', 0, MAP, format}
>      -- function name and id are unique
>      log.info("create index _func:primary")
>      _index:insert{_func.id, 0, 'primary', 'tree', {unique = true}, {{0, 'unsigned'}}}
> @@ -231,7 +230,7 @@ local function initial_1_7_5()
>      format[3] = {name='name', type='string'}
>      format[4] = {name='type', type='string'}
>      format[5] = {name='auth', type='map'}
> -    def = _space:insert{_user.id, ADMIN, '_user', 'memtx', 0, MAP, format}
> +    _space:insert{_user.id, ADMIN, '_user', 'memtx', 0, MAP, format}
>      -- user name and id are unique
>      log.info("create index _func:primary")
>      _index:insert{_user.id, 0, 'primary', 'tree', {unique = true}, {{0, 'unsigned'}}}
> @@ -251,7 +250,7 @@ local function initial_1_7_5()
>      format[3] = {name='object_type', type='string'}
>      format[4] = {name='object_id', type='unsigned'}
>      format[5] = {name='privilege', type='unsigned'}
> -    def = _space:insert{_priv.id, ADMIN, '_priv', 'memtx', 0, MAP, format}
> +    _space:insert{_priv.id, ADMIN, '_priv', 'memtx', 0, MAP, format}
>      -- user id, object type and object id are unique
>      log.info("create index primary on _priv")
>      _index:insert{_priv.id, 0, 'primary', 'tree', {unique = true}, {{1, 'unsigned'}, {2, 'string'}, {3, 'unsigned'}}}
> @@ -580,7 +579,7 @@ local function upgrade_to_2_1_0()
>      -- Now, abscent field means NULL, so we can safely set second
>      -- field in format, marking it nullable.
>      log.info("Add nullable value field to space _schema")
> -    local format = {}
> +    format = {}
>      format[1] = {type='string', name='key'}
>      format[2] = {type='any', name='value', is_nullable=true}
>      box.space._schema:format(format)
> @@ -734,7 +733,7 @@ local function upgrade_collation_to_2_1_3()
>  
>      local id = 4
>      for _, collation in ipairs(coll_lst) do
> -        for i, strength in ipairs(coll_strengths) do
> +        for _, strength in ipairs(coll_strengths) do
>              local coll_name = 'unicode_' .. collation.name .. "_" .. strength.s
>              log.info("creating collation %s", coll_name)
>              box.space._collation:replace{id, coll_name, ADMIN, "ICU", collation.loc_str, strength.opt }
> -- 
> 2.23.0
> 

-- 
sergeyb@