router: relax checks in auto disable

Router's API is protected until the configuration is done, as accessing
router's functions at that time is not safe and can cause low level
errors.

Let's relax checks in this protection. The thrown error messages are
incorrect from now on: router can be started on unconfigured
instance, when box_cfg_mode is 'manual'. box.info.status in such case
will be 'unconfigured', not 'running', we shouldn't rely on it either.

NO_DOC=<documentation is correct>

test/router-luatest/router_test.lua

@@ -458,40 +458,20 @@ g.test_enable_disable = function(g)
     -- gh-291: router enable/disable
     --
     local router = vtest.router_new(g, 'router_1')
-    -- do not allow router's configuration to complete
-    router:exec(function()
-        _G.ivshard.router.internal.errinj.ERRINJ_CFG_DELAY = true
-    end)
     router:exec(function(cfg)
         ivtest.clear_test_cfg_options(cfg)
-        rawset(_G, 'fiber_static', ifiber.new(ivshard.router.cfg, cfg))
-        rawset(_G, 'fiber_new', ifiber.new(ivshard.router.new,
-                                           'new_router', cfg))
+        -- Do not allow router's configuration to complete.
+        _G.ivshard.router.internal.errinj.ERRINJ_CFG_DELAY = true
+        rawset(_G, 'fiber_static', ifiber.create(ivshard.router.cfg, cfg))
+        rawset(_G, 'fiber_new', ifiber.create(ivshard.router.new,
+                                              'new_router', cfg))
         _G.fiber_static:set_joinable(true)
         _G.fiber_new:set_joinable(true)
+        local routers = ivshard.router.internal.routers
+        rawset(_G, 'static_router', routers._static_router)
+        rawset(_G, 'new_router', routers.new_router)
     end, {global_cfg})
 
-    local err1, err2 = router:exec(function()
-        -- emulate unconfigured box
-        local old_box_cfg = box.cfg
-        box.cfg = function(...) return old_box_cfg(...) end
-
-        rawset(_G, 'static_router', ivshard.router.internal.routers._static_router)
-        rawset(_G, 'new_router', ivshard.router.internal.routers.new_router)
-        local _, err_1 = pcall(_G.static_router.info, _G.static_router)
-        local _, err_2 = pcall(_G.new_router.info, _G.new_router)
-
-        box.cfg = old_box_cfg
-        return err_1, err_2
-    end)
-    assert_errors_equals(err1, err2, 'box seems not to be configured')
-
-    -- set box status to loading
-    router:exec(function()
-        rawset(_G, 'old_box_info', box.info)
-        box.info = {status = 'loading'}
-    end)
-
     local echo_func = function()
         return router:exec(function(timeout)
             local echo = function(router)
@@ -504,15 +484,7 @@ g.test_enable_disable = function(g)
         end, {vtest.wait_timeout})
     end
 
-    err1, err2 = echo_func()
-    assert_errors_equals(err1, err2, 'instance status is "loading"')
-
-    -- restore proper box configuration
-    router:exec(function()
-        box.info = _G.old_box_info
-    end)
-
-    err1, err2 = echo_func()
+    local err1, err2 = echo_func()
     assert_errors_equals(err1, err2, 'router is not configured')
 
     -- unblock router's configuration and wait until it's finished
@@ -661,8 +633,9 @@ g.test_router_box_cfg_mode = function(g)
         local box_cfg = box.cfg
         box.cfg = function() end
         ivshard.router.cfg(cfg)
+        local router = ivshard.router.new('router', cfg)
         local opts = {timeout = iwait_timeout}
-        local res, err = ivshard.router.callrw(1, 'echo', {1}, opts)
+        local res, err = router:callrw(1, 'echo', {1}, opts)
         ilt.assert_equals(err, nil)
         ilt.assert_equals(res, 1)
         box.cfg = box_cfg

vshard/router/init.lua

@@ -1698,20 +1698,7 @@ end
 -- the beginning of instance's lifetime.
 --
 local function router_api_call_unsafe(func, router, ...)
-    -- box.info is quite expensive. Avoid calling it again when the instance
-    -- is finally loaded.
-    if not M.is_loaded then
-        if type(box.cfg) == 'function' then
-            local msg = 'box seems not to be configured'
-            return error(lerror.vshard(lerror.code.ROUTER_IS_DISABLED, msg))
-        end
-        local status = box.info.status
-        if status ~= 'running' then
-            local msg = ('instance status is "%s"'):format(status)
-            return error(lerror.vshard(lerror.code.ROUTER_IS_DISABLED, msg))
-        end
-        M.is_loaded = true
-    end
+    -- Router can be started on instance with unconfigured box.cfg.
     if not router.is_configured then
         local msg = 'router is not configured'
         return error(lerror.vshard(lerror.code.ROUTER_IS_DISABLED, msg))