Raise error when non-array arguments passed to server:exec

An error will be raised if the non-array arguments have been passed to
the `server:exec()`.

Resolves #230

Author: Oleg Chaplashkin

CHANGELOG.md

@@ -46,6 +46,7 @@
 - Auto-require `luatest` module in `Server:exec()` function where it is available
   via the corresponding upvalue.
 - Add new function `tarantool.skip_if_not_enterprise`.
+- Raise an error when non-array arguments passed to the `server:exec()`.
 
 ## 0.5.7
 

luatest/server.lua

@@ -504,6 +504,19 @@ local function exec_tail(ok, ...)
     end
 end
 
+-- Check that the passed `args` to the `fn` function are an array.
+local function are_fn_args_array(fn, args)
+    local fn_details = debug.getinfo(fn)
+    if args and #args ~= fn_details.nparams then
+        for k, _ in pairs(args) do
+            if type(k) ~= 'number' then
+                return false
+            end
+        end
+    end
+    return true
+end
+
 --- Run given function on the server.
 --
 -- Much like `Server:eval`, but takes a function instead of a string.
@@ -562,6 +575,11 @@ function Server:exec(fn, args, options)
         error(err, 2)
     end
 
+    if not are_fn_args_array(fn, args) then
+        error(('bad argument #3 for exec at %s: an array is required')
+            :format(utils.get_fn_location(fn)))
+    end
+
     return exec_tail(self.net_box:eval([[
         local dump, args, passthrough_ups = ...
         local fn = loadstring(dump)

luatest/utils.lua

@@ -142,5 +142,10 @@ function utils.upvalues(fn)
     return ret
 end
 
+function utils.get_fn_location(fn)
+    local fn_details = debug.getinfo(fn)
+    local fn_source = fn_details.source:split('/')
+    return ('%s:%s'):format(fn_source[#fn_source], fn_details.linedefined)
+end
 
 return utils

test/malformed_args_test.lua

@@ -0,0 +1,80 @@
+local fio = require('fio')
+local t = require('luatest')
+
+local g = t.group()
+local Server = t.Server
+
+local root = fio.dirname(fio.dirname(fio.abspath(package.search('test.helper'))))
+local datadir = fio.pathjoin(root, 'tmp', 'malformed_args')
+local command = fio.pathjoin(root, 'test', 'server_instance.lua')
+
+g.before_all(function()
+    fio.rmtree(datadir)
+
+    local log = fio.pathjoin(datadir, 'malformed_args_server.log')
+    g.server = Server:new({
+        command = command,
+        workdir = datadir,
+        env = {
+            TARANTOOL_LOG = log
+        },
+        http_port = 8186,
+        net_box_port = 3139,
+    })
+    fio.mktree(g.server.workdir)
+
+    g.server:start()
+    t.helpers.retrying({timeout = 2}, function()
+        g.server:http_request('get', '/ping')
+    end)
+
+    g.server:connect_net_box()
+end)
+
+g.after_all(function()
+    g.server:drop()
+    fio.rmtree(datadir)
+end)
+
+g.test_exec_correct_args = function()
+    local a = g.server:exec(function(a, b) return a + b end, {1, 1})
+    t.assert_equals(a, 2)
+end
+
+g.test_exec_no_args = function()
+    local a = g.server:exec(function() return 1 + 1 end)
+    t.assert_equals(a, 2)
+end
+
+g.test_exec_specific_args = function()
+    -- nil
+    local a = g.server:exec(function(a) return a end)
+    t.assert_equals(a, nil)
+
+    -- too few args
+    local b, c = g.server:exec(function(b, c) return b, c end, {1})
+    t.assert_equals(b, 1)
+    t.assert_equals(c, nil)
+
+    -- too many args
+    local d = g.server:exec(function(d) return d end, {1, 2})
+    t.assert_equals(d, 1)
+end
+
+g.test_exec_non_array_args = function()
+    local function f1()
+        g.server:exec(function(a, b, c) return a, b, c end, {a="a", 2, 3})
+    end
+
+    local function f2()
+        g.server:exec(function(a, b, c) return a, b, c end, {1, a="a", 2})
+    end
+
+    local function f3()
+        g.server:exec(function(a, b, c) return a, b, c end, {1, 2, a="a"})
+    end
+
+    t.assert_error_msg_contains("bad argument #3 for exec at malformed_args_test.lua:66:", f1)
+    t.assert_error_msg_contains("bad argument #3 for exec at malformed_args_test.lua:70:", f2)
+    t.assert_error_msg_contains("bad argument #3 for exec at malformed_args_test.lua:74:", f3)
+end