Add luacheck integration

Patch reimplements commit 'Run luacheck on CI, fix warnings'
(b660d8e) added for http v2 and later
reverted in scope of issue with discard v2. File http/mime_types.lua
contains duplicate items in a table, I don't know what items can be
removed so I just ignored a file in a luacheck configuration file.

Follows up #95
Part of #134

Author: ligurio

.github/workflows/check_on_push.yaml

@@ -0,0 +1,27 @@
+name: Static analysis
+
+on:
+  push:
+  pull_request:
+
+jobs:
+  static-analysis:
+    if: |
+      github.event_name == 'push' ||
+      github.event_name == 'pull_request' && github.event.pull_request.head.repo.full_name != github.repository
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@master
+
+    - name: Setup Tarantool
+      uses: tarantool/setup-tarantool@v1
+      with:
+        tarantool-version: '2.8'
+
+    - name: Setup luacheck
+      run: tarantoolctl rocks install luacheck 0.25.0
+
+    - run: cmake -S . -B build
+
+    - name: Run luacheck
+      run: make -C build luacheck

.luacheckrc

@@ -0,0 +1,35 @@
+std = "luajit"
+globals = {"box", "_TARANTOOL", "tonumber64", "utf8"}
+ignore = {
+    -- Accessing an undefined field of a global variable <debug>.
+    "143/debug",
+    -- Accessing an undefined field of a global variable <os>.
+    "143/os",
+    -- Accessing an undefined field of a global variable <string>.
+    "143/string",
+    -- Accessing an undefined field of a global variable <table>.
+    "143/table",
+    -- Unused argument <self>.
+    "212/self",
+    -- Redefining a local variable.
+    "411",
+    -- Redefining an argument.
+    "412",
+    -- Shadowing a local variable.
+    "421",
+    -- Shadowing an upvalue.
+    "431",
+    -- Shadowing an upvalue argument.
+    "432",
+}
+
+include_files = {
+    "**/*.lua",
+}
+
+exclude_files = {
+    "build/**/*.lua",
+    ".rocks/**/*.lua",
+    ".git/**/*.lua",
+    "http/mime_types.lua",
+}

CMakeLists.txt

@@ -7,6 +7,7 @@ endif()
 set(CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake" ${CMAKE_MODULE_PATH})
 
 find_package(LuaTest)
+find_package(LuaCheck)
 
 # Find Tarantool and Lua dependecies
 set(TARANTOOL_FIND_REQUIRED ON)
@@ -18,6 +19,12 @@ set(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -Wall -Wextra")
 
 add_subdirectory(http)
 
+add_custom_target(luacheck
+  COMMAND ${LUACHECK} ${PROJECT_SOURCE_DIR}
+  WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+  COMMENT "Run luacheck"
+)
+
 add_custom_target(luatest
   COMMAND ${LUATEST} -v
   WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}

README.md

@@ -5,6 +5,7 @@ align="right">
 
 # HTTP server for Tarantool 1.7.5+
 
+[![Static analysis](https://github.com/tarantool/http/actions/workflows/check_on_push.yaml/badge.svg)](https://github.com/tarantool/http/actions/workflows/check_on_push.yaml)
 [![Test](https://github.com/tarantool/http/actions/workflows/test.yml/badge.svg)](https://github.com/tarantool/http/actions/workflows/test.yml)
 
 > **Note:** In Tarantool 1.7.5+, a full-featured HTTP client is available aboard.

cmake/FindLuaCheck.cmake

@@ -0,0 +1,12 @@
+find_program(LUACHECK luacheck
+    HINTS .rocks/
+    PATH_SUFFIXES bin
+    DOC "Lua static analyzer"
+)
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(LuaCheck
+    REQUIRED_VARS LUACHECK
+)
+
+mark_as_advanced(LUACHECK)

http/server.lua

@@ -163,7 +163,6 @@ local function request_content_type(self)
 end
 
 local function post_param(self, name)
-    local content_type = self:content_type()
     if self:content_type() == 'multipart/form-data' then
         -- TODO: do that!
         rawset(self, 'post_params', {})
@@ -213,7 +212,7 @@ local function catfile(...)
         return
     end
 
-    for i, pe in pairs(sp) do
+    for _, pe in pairs(sp) do
         if path == nil then
             path = pe
         elseif string.match(path, '.$') ~= '/' then
@@ -441,7 +440,7 @@ local function render(tx, opts)
     return resp
 end
 
-local function iterate(tx, gen, param, state)
+local function iterate(_, gen, param, state)
     return setmetatable({ body = { gen = gen, param = param, state = state } },
         response_mt)
 end
@@ -837,7 +836,7 @@ local function process_client(self, s, peer)
         };
         for k, v in pairs(hdrs) do
             if type(v) == 'table' then
-                for i, sv in pairs(v) do
+                for _, sv in pairs(v) do
                     table.insert(response, sprintf("%s: %s\r\n", ucfirst(k), sv))
                 end
             else
@@ -857,7 +856,7 @@ local function process_client(self, s, peer)
             if not s:write(response) then
                 break
             end
-            response = nil
+            response = nil -- luacheck: no unused
             -- Transfer-Encoding: chunked
             for _, part in gen, param, state do
                 part = tostring(part)
@@ -916,7 +915,7 @@ local function match_route(self, method, route)
     local fit
     local stash = {}
 
-    for k, r in pairs(self.routes) do
+    for _, r in pairs(self.routes) do
         if r.method == method or r.method == 'ANY' then
             local m = { string.match(route, r.match)  }
             local nfit
@@ -980,7 +979,7 @@ local function url_for_route(r, args, query)
         args = {}
     end
     local name = r.path
-    for i, sn in pairs(r.stash) do
+    for _, sn in pairs(r.stash) do
         local sv = args[sn]
         if sv == nil then
             sv = ''
@@ -1137,7 +1136,7 @@ local function add_route(self, opts, sub)
 
     opts.match = '^' .. opts.match .. '$'
 
-    estash = nil
+    estash = nil -- luacheck: no unused
 
     opts.stash = stash
     opts.sub = sub
@@ -1196,7 +1195,7 @@ local function httpd_start(self)
     local server = socket.tcp_server(self.host, self.port,
                      { name = 'http',
                        handler = function(...)
-                           local res = process_client(self, ...)
+                           process_client(self, ...)
                      end})
     if server == nil then
         error(sprintf("Can't create tcp_server: %s", errno.strerror()))