lua: fix bug with discarding arguments in box.func:call()

Fixes incorrect handling of variable number of arguments in box.func:call().

Closes #6405

changelogs/unreleased/gh-6405-discarding-arguments-in-box-func-call.md

+## bugfix/lua
+
+* Fixed incorrect handling of variable number of arguments in box.func:call() (gh-6405).

src/box/lua/schema.lua

@@ -2663,7 +2663,7 @@ func_mt.call = function(func, args)
     if type(args) ~= 'table' then
         error('Use func:call(table)')
     end
-    return box.schema.func.call(func.name, unpack(args))
+    return box.schema.func.call(func.name, unpack(args, 1, table.maxn(args)))
 end
 
 function box.schema.func.bless(func)

test/box/gh-6405-discarding-arguments-in-box-func-call.result

+-- test-run result file version 2
+args_type = function(...)                     \
+    local type_table = {}                     \
+    for i = 1, select('#', ...) do            \
+        type_table[i] = type(select(i, ...))  \
+    end                                       \
+    return type_table                         \
+end                                           \
+
+box.schema.func.create('args_type')
+ | ---
+ | ...
+
+box_call = box.func.args_type:call({1, nil, 3})
+ | ---
+ | ...
+lua_call = args_type(1, nil, 3)
+ | ---
+ | ...
+assert(table.equals(box_call, lua_call))
+ | ---
+ | - true
+ | ...
+box_call = box.func.args_type:call({'string', nil, 3})
+ | ---
+ | ...
+lua_call = args_type('string', nil, 3)
+ | ---
+ | ...
+assert(table.equals(box_call, lua_call))
+ | ---
+ | - true
+ | ...
+box_call = box.func.args_type:call({1, nil, 7, nil, 3, 5, nil, 9, 10})
+ | ---
+ | ...
+lua_call = args_type(1, nil, 7, nil, 3, 5, nil, 9, 10)
+ | ---
+ | ...
+assert(table.equals(box_call, lua_call))
+ | ---
+ | - true
+ | ...
+box_call = box.func.args_type:call({1, 2, 3, 'string'})
+ | ---
+ | ...
+lua_call = args_type(1, 2, 3, 'string')
+ | ---
+ | ...
+assert(table.equals(box_call, lua_call))
+ | ---
+ | - true
+ | ...
+box_call = box.func.args_type:call({nil, nil, 3})
+ | ---
+ | ...
+lua_call = args_type(nil, nil, 3)
+ | ---
+ | ...
+assert(table.equals(box_call, lua_call))
+ | ---
+ | - true
+ | ...
+
+box.schema.func.drop('args_type')
+ | ---
+ | ...

test/box/gh-6405-discarding-arguments-in-box-func-call.test.lua

+args_type = function(...)                     \
+    local type_table = {}                     \
+    for i = 1, select('#', ...) do            \
+        type_table[i] = type(select(i, ...))  \
+    end                                       \
+    return type_table                         \
+end                                           \
+
+box.schema.func.create('args_type')
+
+box_call = box.func.args_type:call({1, nil, 3})
+lua_call = args_type(1, nil, 3)
+assert(table.equals(box_call, lua_call))
+box_call = box.func.args_type:call({'string', nil, 3})
+lua_call = args_type('string', nil, 3)
+assert(table.equals(box_call, lua_call))
+box_call = box.func.args_type:call({1, nil, 7, nil, 3, 5, nil, 9, 10})
+lua_call = args_type(1, nil, 7, nil, 3, 5, nil, 9, 10)
+assert(table.equals(box_call, lua_call))
+box_call = box.func.args_type:call({1, 2, 3, 'string'})
+lua_call = args_type(1, 2, 3, 'string')
+assert(table.equals(box_call, lua_call))
+box_call = box.func.args_type:call({nil, nil, 3})
+lua_call = args_type(nil, nil, 3)
+assert(table.equals(box_call, lua_call))
+
+box.schema.func.drop('args_type')