storage: preserve original error on function fail

test/storage-luatest/storage_1_test.lua

@@ -674,3 +674,55 @@ test_group.test_info_disable_consistency = function(g)
         ilt.assert(res.is_enabled)
     end, {global_cfg})
 end
+
+local function test_error_msg_is_preserved_template(add_to_schema, g)
+    g.replica_1_a:exec(function(add_to_schema)
+        rawset(_G, 'test_fail', function()
+            box.begin()
+            error('test_error')
+        end)
+        if add_to_schema then
+            box.schema.func.create('test_fail')
+        end
+        local status, err = ivshard.storage.call(1, 'read', 'test_fail', {})
+        ilt.assert_not(status)
+        local err_msg = tostring(err)
+        ilt.assert_str_contains(err_msg, 'test_error')
+        ilt.assert_not_str_contains(err_msg, 'Transaction is active')
+        rawset(_G, 'test_fail', nil)
+        if add_to_schema then
+            box.schema.func.drop('test_fail')
+        end
+    end, {add_to_schema})
+end
+
+test_group.test_error_msg_is_preserved = function(g)
+    test_error_msg_is_preserved_template(false, g)
+    test_error_msg_is_preserved_template(true, g)
+end
+
+local function test_local_call_return_type_consistency_template(
+    add_to_schema, g)
+    g.replica_1_a:exec(function(add_to_schema)
+        rawset(_G, 'test_return_tuple', function()
+            return box.tuple.new({100, 200, 'tuple'})
+        end)
+        if add_to_schema then
+            box.schema.func.create('test_return_tuple')
+        end
+        local status, result = ivshard.storage.call(
+            1, 'read', 'test_return_tuple', {})
+        ilt.assert(status)
+        ilt.assert_equals(type(result), 'table')
+        ilt.assert_equals(result, {100, 200, 'tuple'})
+        if add_to_schema then
+            box.schema.func.drop('test_return_tuple')
+        end
+        _G.test_return_tuple = nil
+    end, {add_to_schema})
+end
+
+test_group.test_local_call_return_type_consistency = function(g)
+    test_local_call_return_type_consistency_template(true, g)
+    test_local_call_return_type_consistency_template(false, g)
+end

vshard/storage/init.lua

@@ -7,6 +7,7 @@ local trigger = require('internal.trigger')
 local ffi = require('ffi')
 local json_encode = require('json').encode
 local yaml_encode = require('yaml').encode
+local msgpack = require('msgpack')
 local fiber_clock = lfiber.clock
 local fiber_yield = lfiber.yield
 local netbox_self = netbox.self
@@ -260,6 +261,23 @@ else
     end
 end
 
+--
+-- This is copy-paste from the net_box.lua handle_eval_result.
+--
+local function handle_results(status, ...)
+    if not status then
+        box.rollback()
+        return status, box.error.new(box.error.PROC_LUA, (...))
+    end
+    local results = {...}
+    for i = 1, select('#', ...) do
+        if type(results[i]) == 'cdata' then
+            results[i] = msgpack.decode(msgpack.encode(results[i]))
+        end
+    end
+    return status, unpack(results)
+end
+
 --
 -- Invoke a function on this instance. Arguments are unpacked into the function
 -- as arguments.
@@ -284,7 +302,12 @@ local_call = function(func_name, args)
     if not func then
         return pcall(netbox_self_call, netbox_self, func_name, args)
     end
-    return pcall(func.call, func, args)
+    -- If the function is called directly, fails, and leaves an uncommitted
+    -- transaction, then in Tarantool versions before 3.0.0-beta1-18,
+    -- the original error is replaced by the "Transaction is active" error.
+    -- We manually check if the function returned an error. If so, we
+    -- rollback the transaction to reveal the original error.
+    return handle_results(pcall(func.call, func, args))
 end
 
 end