Re: [Tarantool-patches] [PATCH 3/6] Fix luacheck warnings in src/box/lua/

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Thanks for the patch!

Consider more fixes below and on the branch in a separate commit.
That allowed to remove some warning mutes from the luacheck
config.

Also luacheck discovered two bugs, which were muted in luacheck
config. I fixed them in 2 separate commits so as they could be
backported.

So in total there are +1 commit with review fixes and +2 self
sufficient commits, which should not be squashed.

The 2 new commits I sent as separate letters.

====================

    Review fixes: src/box/lua

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 ad71a3fe2..06bf3f281 100644
--- a/src/box/lua/feedback_daemon.lua
+++ b/src/box/lua/feedback_daemon.lua
@@ -60,7 +60,7 @@ 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 b671eb7a2..8d5dfa590 100644
--- a/src/box/lua/load_cfg.lua
+++ b/src/box/lua/load_cfg.lua
@@ -430,7 +430,6 @@ 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
diff --git a/src/box/lua/net_box.lua b/src/box/lua/net_box.lua
index 07fa54c38..1e351bb31 100644
--- a/src/box/lua/net_box.lua
+++ b/src/box/lua/net_box.lua
@@ -38,10 +38,6 @@ 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_KEY     = 0x31
 local IPROTO_ERROR_STACK   = 0x52
@@ -155,7 +151,7 @@ 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
@@ -425,7 +421,7 @@ 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
@@ -647,7 +643,7 @@ 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
@@ -711,7 +707,8 @@ 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
@@ -729,7 +726,6 @@ 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)
@@ -803,8 +799,7 @@ local function create_transport(host, port, user, password, callback,
                 local status = hdr[IPROTO_STATUS_KEY]
                 local response_schema_version = hdr[IPROTO_SCHEMA_VERSION_KEY]
                 if status ~= 0 then
-                    local body
-                    body, body_end = decode(body_rpos)
+                    local body = decode(body_rpos)
                     return error_sm(E_NO_CONNECTION, body[IPROTO_ERROR_KEY])
                 end
                 if schema_version == nil then
@@ -813,8 +808,7 @@ 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
         until response[select1_id] and response[select2_id] and
@@ -830,14 +824,11 @@ 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
@@ -954,7 +945,7 @@ 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
@@ -1601,7 +1592,6 @@ 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
diff --git a/src/box/lua/schema.lua b/src/box/lua/schema.lua
index 85fcca562..545abe714 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 fio = require('fio')
@@ -274,7 +273,6 @@ 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])
@@ -582,9 +580,9 @@ 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
@@ -844,7 +842,7 @@ 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")
@@ -1281,7 +1279,6 @@ end
 
 -- global struct port instance to use by select()/get()
 local port_tuple = ffi.new('struct port_tuple')
-local port_tuple_entry_t = ffi.typeof('struct port_tuple_entry')
 
 -- Helper function to check space:method() usage
 local function check_space_arg(space, method)
@@ -1499,7 +1496,8 @@ 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
@@ -1532,7 +1530,8 @@ 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_tuple)
@@ -1554,7 +1553,7 @@ 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)
@@ -2680,7 +2679,7 @@ 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..6d5df1ae7 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
diff --git a/src/box/lua/upgrade.lua b/src/box/lua/upgrade.lua
index 6b8ece513..f95b1ae4a 100644
--- a/src/box/lua/upgrade.lua
+++ b/src/box/lua/upgrade.lua
@@ -52,7 +52,6 @@ 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
             local key = {}
             for _k2, parts in ipairs(pk.parts) do