lua: fix for option pid_file overwritten by tarantoolctl

During startup tarantoolctl ignores 'pid_file' option and set it to
default value.
This cause a fault if user tries to execute config with option set.
In case of being started with tarantoolctl shadow this option with
additional wrapper around box.cfg.

Closes #3214

extra/dist/tarantoolctl.in

@@ -527,6 +527,13 @@ local function start()
         end
         os.exit(1)
     end
+    local old_call = getmetatable(box.cfg).__call
+    getmetatable(box.cfg).__call = function(old_cfg, cfg)
+        if old_cfg.pid_file ~= nil and cfg ~= nil and cfg.pid_file ~= nil then
+            cfg.pid_file = old_cfg.pid_file
+        end
+        old_call(old_cfg, cfg)
+    end
     return 0
 end
 

test/box/cfg.result

@@ -365,6 +365,36 @@ test_run:cmd("cleanup server cfg_tester4")
 - true
 ...
 --------------------------------------------------------------------------------
+-- Check fix for pid_file option overwritten by tarantoolctl
+--------------------------------------------------------------------------------
+test_run:cmd('create server cfg_tester5 with script = "box/lua/cfg_test1.lua"')
+---
+- true
+...
+test_run:cmd("start server cfg_tester5")
+---
+- true
+...
+test_run:cmd('switch cfg_tester5')
+---
+- true
+...
+box.cfg{pid_file = "current.pid"}
+---
+...
+test_run:cmd("switch default")
+---
+- true
+...
+test_run:cmd("stop server cfg_tester5")
+---
+- true
+...
+test_run:cmd("cleanup server cfg_tester5")
+---
+- true
+...
+--------------------------------------------------------------------------------
 -- Check that 'vinyl_dir' cfg option is not checked as long as
 -- there is no vinyl indexes (issue #2664)
 --------------------------------------------------------------------------------

test/box/cfg.test.lua

@@ -69,6 +69,18 @@ test_run:cmd("switch default")
 test_run:cmd("stop server cfg_tester4")
 test_run:cmd("cleanup server cfg_tester4")
 
+--------------------------------------------------------------------------------
+-- Check fix for pid_file option overwritten by tarantoolctl
+--------------------------------------------------------------------------------
+
+test_run:cmd('create server cfg_tester5 with script = "box/lua/cfg_test1.lua"')
+test_run:cmd("start server cfg_tester5")
+test_run:cmd('switch cfg_tester5')
+box.cfg{pid_file = "current.pid"}
+test_run:cmd("switch default")
+test_run:cmd("stop server cfg_tester5")
+test_run:cmd("cleanup server cfg_tester5")
+
 --------------------------------------------------------------------------------
 -- Check that 'vinyl_dir' cfg option is not checked as long as
 -- there is no vinyl indexes (issue #2664)