[Tarantool-patches] [PATCH 5/6] Fix luacheck warnings in src/lua/

[sergeyb@tarantool.org]

From: Sergey Bronnikov <sergeyb@tarantool.org>

Part of #4681

Reviewed-by: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
Reviewed-by: Igor Munkin <imun@tarantool.org>

Co-authored-by: Vladislav Shpilevoy <v.shpilevoy@tarantool.org>
Co-authored-by: Igor Munkin <imun@tarantool.org>
---
 .luacheckrc            | 28 ++++++++++++++++++++++++----
 src/lua/argparse.lua   |  3 ++-
 src/lua/buffer.lua     |  4 ++--
 src/lua/clock.lua      |  2 +-
 src/lua/crypto.lua     |  4 ++--
 src/lua/csv.lua        |  5 ++---
 src/lua/digest.lua     |  2 +-
 src/lua/env.lua        |  2 +-
 src/lua/fiber.lua      |  4 ++--
 src/lua/fio.lua        | 30 ++++++++++++++----------------
 src/lua/help.lua       |  7 ++-----
 src/lua/httpc.lua      |  3 ---
 src/lua/init.lua       |  4 ++--
 src/lua/msgpackffi.lua | 22 +++++++++-------------
 src/lua/socket.lua     | 16 ++++++++--------
 src/lua/string.lua     |  1 -
 src/lua/swim.lua       |  2 +-
 src/lua/tap.lua        |  4 ----
 src/lua/trigger.lua    |  3 ---
 19 files changed, 73 insertions(+), 73 deletions(-)

diff --git a/.luacheckrc b/.luacheckrc
index b917eb927..fb8b9dfb3 100644
--- a/.luacheckrc
+++ b/.luacheckrc
@@ -1,9 +1,14 @@
 std = "luajit"
 globals = {"box", "_TARANTOOL"}
 ignore = {
-    "212/self", -- Unused argument <self>.
-    "411",      -- Redefining a local variable.
-    "431",      -- Shadowing an upvalue.
+    "143/debug",  -- Accessing an undefined field of a global variable <debug>.
+    "143/string", -- Accessing an undefined field of a global variable <string>.
+    "143/table",  -- Accessing an undefined field of a global variable <table>.
+    "212/self",   -- Unused argument <self>.
+    "411",        -- Redefining a local variable.
+    "421",        -- Shadowing a local variable.
+    "431",        -- Shadowing an upvalue.
+    "432",        -- Shadowing an upvalue argument.
 }
 
 
@@ -14,7 +19,7 @@ include_files = {
 
 exclude_files = {
     "build/**/*.lua",
-    "src/**/*.lua",
+    "src/box/**/*.lua",
     "test-run/**/*.lua",
     "test/**/*.lua",
     "third_party/**/*.lua",
@@ -27,3 +32,18 @@ files["extra/dist/tarantoolctl.in"] = {
         "122", -- https://github.com/tarantool/tarantool/issues/4929
     },
 }
+files["src/lua/help.lua"] = {
+    globals = {"help", "tutorial"}, -- globals defined for interactive mode.
+}
+files["src/lua/init.lua"] = {
+    globals = {"dostring"}, -- miscellaneous global function definition.
+    ignore = {
+        "122/os",      -- set tarantool specific behaviour for os.exit.
+        "142/package", -- add custom functions into Lua package namespace.
+    },
+}
+files["src/lua/swim.lua"] = {
+    ignore = {
+        "212/m", -- respect swim module code style.
+    },
+}
diff --git a/src/lua/argparse.lua b/src/lua/argparse.lua
index faa0ae130..6c8f10fc1 100644
--- a/src/lua/argparse.lua
+++ b/src/lua/argparse.lua
@@ -91,7 +91,8 @@ local function convert_parameter(name, convert_from, convert_to)
 end
 
 local function parameters_parse(t_in, options)
-    local t_out, t_in = {}, t_in or {}
+    local t_out = {}
+    t_in = t_in or {}
 
     -- Prepare a lookup table for options. An option name -> a
     -- type name to convert a parameter into or true (which means
diff --git a/src/lua/buffer.lua b/src/lua/buffer.lua
index 9aac82b39..00846bb20 100644
--- a/src/lua/buffer.lua
+++ b/src/lua/buffer.lua
@@ -182,7 +182,7 @@ local ibuf_methods = {
     unused = ibuf_unused;
 }
 
-local function ibuf_tostring(ibuf)
+local function ibuf_tostring(self)
     return '<ibuf>'
 end
 local ibuf_mt = {
@@ -193,7 +193,7 @@ local ibuf_mt = {
 
 ffi.metatype(ibuf_t, ibuf_mt);
 
-local function ibuf_new(arg, arg2)
+local function ibuf_new(arg)
     local buf = ffi.new(ibuf_t)
     local slabc = builtin.tarantool_lua_slab_cache()
     builtin.ibuf_create(buf, slabc, READAHEAD)
diff --git a/src/lua/clock.lua b/src/lua/clock.lua
index 60c78663c..fee43ccde 100644
--- a/src/lua/clock.lua
+++ b/src/lua/clock.lua
@@ -33,7 +33,7 @@ clock.bench = function(fun, ...)
     overhead = clock.proc() - overhead
     local start_time = clock.proc()
     local res = {0, fun(...)}
-    res[1] = clock.proc() - start_time - overhead, res
+    res[1] = clock.proc() - start_time - overhead
     return res
 end
 
diff --git a/src/lua/crypto.lua b/src/lua/crypto.lua
index bf3064c70..f31708e29 100644
--- a/src/lua/crypto.lua
+++ b/src/lua/crypto.lua
@@ -75,7 +75,7 @@ local function openssl_err_str()
 end
 
 local digests = {}
-for class, name in pairs({
+for class, _ in pairs({
     md2 = 'MD2', md4 = 'MD4', md5 = 'MD5',
     sha1 = 'SHA1', sha224 = 'SHA224',
     sha256 = 'SHA256', sha384 = 'SHA384', sha512 = 'SHA512',
@@ -428,7 +428,7 @@ local public_methods = {
 }
 
 local module_mt = {
-    __serialize = function(s)
+    __serialize = function(self)
         return public_methods
     end,
     __index = public_methods
diff --git a/src/lua/csv.lua b/src/lua/csv.lua
index 7dff2f213..de6726bb7 100644
--- a/src/lua/csv.lua
+++ b/src/lua/csv.lua
@@ -188,10 +188,10 @@ module.dump = function(t, opts, writable)
     if type(writable) == 'nil' then
         result_table = {}
     end
-    for k, line in pairs(t) do
+    for _, line in pairs(t) do
         local first = true
         local output_tuple = {}
-        for k2, field in pairs(line) do
+        for _, field in pairs(line) do
             local strf = tostring(field)
             local buf_new_size = (strf:len() + 1) * 2
             if buf_new_size > bufsz then
@@ -214,7 +214,6 @@ module.dump = function(t, opts, writable)
         else
             writable:write(table.concat(output_tuple))
         end
-        output_tuple = {}
     end
     ffi.C.csv_destroy(csv)
     csv.realloc(buf, 0)
diff --git a/src/lua/digest.lua b/src/lua/digest.lua
index 6ed91cfa2..7f1aea8d0 100644
--- a/src/lua/digest.lua
+++ b/src/lua/digest.lua
@@ -246,7 +246,7 @@ local m = {
     end
 }
 
-for digest, name in pairs(digest_shortcuts) do
+for digest, _ in pairs(digest_shortcuts) do
     m[digest] = function (str)
         return crypto.digest[digest](str)
     end
diff --git a/src/lua/env.lua b/src/lua/env.lua
index dd1616a84..a31b7098f 100644
--- a/src/lua/env.lua
+++ b/src/lua/env.lua
@@ -28,7 +28,7 @@ os.environ = function()
 end
 
 os.setenv = function(key, value)
-    local rv = nil
+    local rv
     if value ~= nil then
         rv = ffi.C.setenv(key, value, 1)
     else
diff --git a/src/lua/fiber.lua b/src/lua/fiber.lua
index 89c17f63d..b14117714 100644
--- a/src/lua/fiber.lua
+++ b/src/lua/fiber.lua
@@ -39,8 +39,8 @@ local stall = fiber.stall
 fiber.stall = nil
 
 local worker_next_task = nil
-local worker_last_task = nil
-local worker_fiber = nil
+local worker_last_task
+local worker_fiber
 
 --
 -- Worker is a singleton fiber for not urgent delayed execution of
diff --git a/src/lua/fio.lua b/src/lua/fio.lua
index 83fddaa0a..b31311b7b 100644
--- a/src/lua/fio.lua
+++ b/src/lua/fio.lua
@@ -329,7 +329,7 @@ fio.abspath = function(path)
         error("Usage: fio.abspath(path)")
     end
     path = path
-    local joined_path = ''
+    local joined_path
     local path_tab = {}
     if string.sub(path, 1, 1) == '/' then
         joined_path = path
@@ -366,7 +366,7 @@ fio.listdir = function(path)
         return t
     end
     local names = string.split(str, "\n")
-    for i, name in ipairs(names) do
+    for _, name in ipairs(names) do
         table.insert(t, name)
     end
     return t
@@ -378,15 +378,15 @@ fio.mktree = function(path, mode)
     end
     path = fio.abspath(path)
 
-    local path = string.gsub(path, '^/', '')
+    path = string.gsub(path, '^/', '')
     local dirs = string.split(path, "/")
 
     local current_dir = "/"
-    for i, dir in ipairs(dirs) do
+    for _, dir in ipairs(dirs) do
         current_dir = fio.pathjoin(current_dir, dir)
         local stat = fio.stat(current_dir)
         if stat == nil then
-            local st, err = fio.mkdir(current_dir, mode)
+            local _, err = fio.mkdir(current_dir, mode)
             -- fio.stat() and fio.mkdir() above are separate calls
             -- and a file system may be changed between them. So
             -- if the error here is due to an existing directory,
@@ -407,27 +407,26 @@ fio.rmtree = function(path)
     if type(path) ~= 'string' then
         error("Usage: fio.rmtree(path)")
     end
-    local status, err
     path = fio.abspath(path)
     local ls, err = fio.listdir(path)
     if err ~= nil then
         return nil, err
     end
-    for i, f in ipairs(ls) do
+    for _, f in ipairs(ls) do
         local tmppath = fio.pathjoin(path, f)
         local st = fio.lstat(tmppath)
         if st then
             if st:is_dir() then
-                st, err = fio.rmtree(tmppath)
+                _, err = fio.rmtree(tmppath)
             else
-                st, err = fio.unlink(tmppath)
+                _, err = fio.unlink(tmppath)
             end
             if err ~= nil  then
                 return nil, err
             end
         end
     end
-    status, err = fio.rmdir(path)
+    local _, err = fio.rmdir(path)
     if err ~= nil then
         return false, string.format("failed to remove %s: %s", path, err)
     end
@@ -453,7 +452,6 @@ fio.copytree = function(from, to)
     if type(from) ~= 'string' or type(to) ~= 'string' then
         error('Usage: fio.copytree(from, to)')
     end
-    local status, reason
     local st = fio.stat(from)
     if not st then
         return false, string.format("Directory %s does not exist", from)
@@ -467,22 +465,22 @@ fio.copytree = function(from, to)
     end
 
     -- create tree of destination
-    status, reason = fio.mktree(to)
+    local _, reason = fio.mktree(to)
     if reason ~= nil then
         return false, reason
     end
-    for i, f in ipairs(ls) do
+    for _, f in ipairs(ls) do
         local ffrom = fio.pathjoin(from, f)
         local fto = fio.pathjoin(to, f)
         local st = fio.lstat(ffrom)
         if st and st:is_dir() then
-            status, reason = fio.copytree(ffrom, fto)
+            _, reason = fio.copytree(ffrom, fto)
             if reason ~= nil then
                 return false, reason
             end
         end
         if st:is_reg() then
-            status, reason = fio.copyfile(ffrom, fto)
+            _, reason = fio.copyfile(ffrom, fto)
             if reason ~= nil then
                 return false, reason
             end
@@ -492,7 +490,7 @@ fio.copytree = function(from, to)
             if reason ~= nil then
                 return false, reason
             end
-            status, reason = fio.symlink(link_to, fto)
+            _, reason = fio.symlink(link_to, fto)
             if reason ~= nil then
                 return false, "can't create symlink in place of existing file "..fto
             end
diff --git a/src/lua/help.lua b/src/lua/help.lua
index 54ff1b5d0..4f024832d 100644
--- a/src/lua/help.lua
+++ b/src/lua/help.lua
@@ -11,10 +11,7 @@ help = { doc.help }
 tutorial = {}
 tutorial[1] = help[1]
 
-local help_function_data = {};
-local help_object_data = {}
-
-local function help_call(table, param)
+local function help_call()
     return help
 end
 
@@ -22,7 +19,7 @@ setmetatable(help, { __call = help_call })
 
 local screen_id = 1;
 
-local function tutorial_call(table, action)
+local function tutorial_call(self, action)
     if action == 'start' then
         screen_id = 1;
     elseif action == 'next' or action == 'more' then
diff --git a/src/lua/httpc.lua b/src/lua/httpc.lua
index 6381c6a1a..9336dcee0 100644
--- a/src/lua/httpc.lua
+++ b/src/lua/httpc.lua
@@ -29,8 +29,6 @@
 --  SUCH DAMAGE.
 --
 
-local fiber = require('fiber')
-
 local driver = package.loaded.http.client
 package.loaded.http = nil
 
@@ -112,7 +110,6 @@ local special_characters = {
     [']'] = true,
     ['<'] = true,
     ['>'] = true,
-    ['>'] = true,
     ['@'] = true,
     [','] = true,
     [';'] = true,
diff --git a/src/lua/init.lua b/src/lua/init.lua
index ff3e74c3c..aea7a7491 100644
--- a/src/lua/init.lua
+++ b/src/lua/init.lua
@@ -144,9 +144,9 @@ local function gen_search_func(path_fn, templates, need_traverse)
 
         local searchpaths = {}
 
-        for _, path in ipairs(paths) do
+        for _, p in ipairs(paths) do
             for _, template in pairs(templates) do
-                table.insert(searchpaths, fio.pathjoin(path, template))
+                table.insert(searchpaths, fio.pathjoin(p, template))
             end
         end
 
diff --git a/src/lua/msgpackffi.lua b/src/lua/msgpackffi.lua
index f01ffaef0..cb7ad5b88 100644
--- a/src/lua/msgpackffi.lua
+++ b/src/lua/msgpackffi.lua
@@ -302,10 +302,6 @@ local function encode(obj)
     return r
 end
 
-local function encode_ibuf(obj, ibuf)
-    encode_r(ibuf, obj, 0)
-end
-
 on_encode(ffi.typeof('uint8_t'), encode_int)
 on_encode(ffi.typeof('uint16_t'), encode_int)
 on_encode(ffi.typeof('uint32_t'), encode_int)
@@ -332,7 +328,6 @@ local decode_r
 
 -- See similar constants in utils.cc
 local DBL_INT_MAX = 1e14 - 1
-local DBL_INT_MIN = -1e14 + 1
 
 local function decode_u8(data)
     local num = ffi.cast(uint8_ptr_t, data[0])[0]
@@ -477,8 +472,7 @@ end
 local function decode_array(data, size)
     assert (type(size) == "number")
     local arr = {}
-    local i
-    for i=1,size,1 do
+    for _ = 1, size do
         table.insert(arr, decode_r(data))
     end
     if not msgpack.cfg.decode_save_metatables then
@@ -490,8 +484,7 @@ end
 local function decode_map(data, size)
     assert (type(size) == "number")
     local map = {}
-    local i
-    for i=1,size,1 do
+    for _ = 1, size do
         local key = decode_r(data);
         local val = decode_r(data);
         map[key] = val
@@ -504,11 +497,15 @@ end
 
 local ext_decoder = {
     -- MP_UNKNOWN_EXTENSION
-    [0] = function(data, len) error("unsupported extension type") end,
+    [0] = function(data, len) error("unsupported extension type") end, -- luacheck: no unused args
     -- MP_DECIMAL
     [1] = function(data, len) local num = ffi.new("decimal_t") builtin.decimal_unpack(data, len, num) return num end,
     -- MP_UUID
-    [2] = function(data, len) local uuid = ffi.new("struct tt_uuid") builtin.uuid_unpack(data, len, uuid) return uuid end,
+    [2] = function(data, len)
+        local uuid = ffi.new("struct tt_uuid")
+        builtin.uuid_unpack(data, len, uuid)
+        return uuid
+    end,
 }
 
 local function decode_ext(data)
@@ -516,7 +513,6 @@ local function decode_ext(data)
     -- mp_decode_extl and mp_decode_decimal
     -- need type code
     data[0] = data[0] - 1
-    local old_data = data[0]
     local len = builtin.mp_decode_extl(data, t)
     local fun = ext_decoder[t[0]]
     if type(fun) == 'function' then
@@ -603,7 +599,7 @@ local function check_offset(offset, len)
     if offset == nil then
         return 1
     end
-    local offset = ffi.cast('ptrdiff_t', offset)
+    offset = ffi.cast('ptrdiff_t', offset)
     if offset < 1 or offset > len then
         error(string.format("offset = %d is out of bounds [1..%d]",
             tonumber(offset), len))
diff --git a/src/lua/socket.lua b/src/lua/socket.lua
index bbdef01e3..2a2c7a32c 100644
--- a/src/lua/socket.lua
+++ b/src/lua/socket.lua
@@ -177,7 +177,7 @@ local function get_iflags(table, flags)
     if type(flags) ~= 'table' then
         flags = { flags }
     end
-    for i, f in pairs(flags) do
+    for _, f in pairs(flags) do
         if table[f] == nil then
             return nil
         end
@@ -665,7 +665,7 @@ local function check_delimiter(self, limit, eols)
     end
 
     local shortest
-    for i, eol in ipairs(eols) do
+    for _, eol in ipairs(eols) do
         local data = ffi.C.memmem(rbuf.rpos, rbuf:size(), eol, #eol)
         if data ~= nil then
             local len = ffi.cast('char *', data) - rbuf.rpos + #eol
@@ -1044,7 +1044,7 @@ local function tcp_connect(host, port, timeout)
         boxerrno(0)
         return s
     end
-    local timeout = timeout or TIMEOUT_INFINITY
+    timeout = timeout or TIMEOUT_INFINITY
     local stop = fiber.clock() + timeout
     local dns = getaddrinfo(host, port, timeout, { type = 'SOCK_STREAM',
         protocol = 'tcp' })
@@ -1052,7 +1052,7 @@ local function tcp_connect(host, port, timeout)
         boxerrno(boxerrno.EINVAL)
         return nil
     end
-    for i, remote in pairs(dns) do
+    for _, remote in pairs(dns) do
         timeout = stop - fiber.clock()
         if timeout <= 0 then
             boxerrno(boxerrno.ETIMEDOUT)
@@ -1319,7 +1319,7 @@ local function lsocket_tcp_getpeername(self)
     return peer.host, tostring(peer.port), peer.family:match("AF_(.*)"):lower()
 end
 
-local function lsocket_tcp_settimeout(self, value, mode)
+local function lsocket_tcp_settimeout(self, value, mode) -- luacheck: no unused args
     check_socket(self)
     self.timeout = value
     -- mode is effectively ignored
@@ -1475,7 +1475,7 @@ local function lsocket_tcp_receive(self, pattern, prefix)
         local result = { prefix }
         local deadline = fiber.clock() + (self.timeout or TIMEOUT_INFINITY)
         repeat
-            local data = read(self, LIMIT_INFINITY, timeout, check_infinity)
+            data = read(self, LIMIT_INFINITY, timeout, check_infinity)
             if data == nil then
                 if not errno_is_transient[self._errno] then
                     return nil, socket_error(self)
@@ -1543,7 +1543,7 @@ lsocket_tcp_mt.__index.send = lsocket_tcp_send;
 -- TCP Constructor and Shortcuts
 --
 
-local function lsocket_tcp()
+local function lsocket_tcp(self)
     local s = socket_new('AF_INET', 'SOCK_STREAM', 'tcp')
     if not s then
         return nil, socket_error(self)
@@ -1567,7 +1567,7 @@ local function lsocket_bind(host, port, backlog)
     if host == nil or port == nil then
         error("Usage: luasocket.bind(host, port [, backlog])")
     end
-    local function prepare(s) return backlog end
+    local function prepare(s) return backlog end -- luacheck: no unused args
     local s = tcp_server_bind(host, port, prepare)
     if not s then
         return nil, boxerrno.strerror()
diff --git a/src/lua/string.lua b/src/lua/string.lua
index 6e12c59ae..d3a846645 100644
--- a/src/lua/string.lua
+++ b/src/lua/string.lua
@@ -233,7 +233,6 @@ local function string_startswith(inp, head, _start, _end)
         return false
     end
     _start = _start - 1
-    _end = _start + head_len - 1
     return memcmp(c_char_ptr(inp) + _start, c_char_ptr(head), head_len) == 0
 end
 
diff --git a/src/lua/swim.lua b/src/lua/swim.lua
index 0859915c9..cdf9d7df0 100644
--- a/src/lua/swim.lua
+++ b/src/lua/swim.lua
@@ -371,7 +371,7 @@ end
 --
 local function swim_member_payload_str(m)
     local ptr = swim_check_member(m, 'member:payload_str()')
-    local cdata, size = swim_member_payload_raw(ptr)
+    local _, size = swim_member_payload_raw(ptr)
     if size > 0 then
         return ffi.string(swim_member_payload_raw(ptr))
     end
diff --git a/src/lua/tap.lua b/src/lua/tap.lua
index 94b080d5a..346724d84 100644
--- a/src/lua/tap.lua
+++ b/src/lua/tap.lua
@@ -53,7 +53,6 @@ local function ok(test, cond, message, extra)
     io.write(string.format("not ok - %s\n", message))
     extra = extra or {}
     if test.trace then
-        local frame = debug.getinfo(3, "Sl")
         extra.trace = traceback()
         extra.filename = extra.trace[#extra.trace].filename
         extra.line = extra.trace[#extra.trace].line
@@ -76,9 +75,6 @@ local function skip(test, message, extra)
     ok(test, true, message.." # skip", extra)
 end
 
-
-local nan = 0/0
-
 local function cmpdeeply(got, expected, extra)
     if type(expected) == "number" or type(got) == "number" then
         extra.got = got
diff --git a/src/lua/trigger.lua b/src/lua/trigger.lua
index 76a582c47..1330ecdd4 100644
--- a/src/lua/trigger.lua
+++ b/src/lua/trigger.lua
@@ -1,7 +1,4 @@
 local fun = require('fun')
-local log = require('log')
-
-local table_clear = require('table.clear')
 
 --
 -- Checks that argument is a callable, i.e. a function or a table
-- 
2.23.0