utubettl: fix work with "ttl" of buried task

Before the patch if a task has been "buried" after it was "taken"
(and the task has "ttr") when the time in `i_next_event` will be
interpreted as "ttl" in `utubettl_fiber_iteration` and the task will
be deleted.

Author: LeonidVas

queue/abstract/driver/utubettl.lua

@@ -343,13 +343,22 @@ end
 
 -- bury task
 function method.bury(self, id)
-    local task = self.space:update(id, {{ '=', i_status, state.BURIED }})
-    if task ~= nil then
-        return process_neighbour(
-            self, task:transform(i_status, 1, state.BURIED), 'bury'
-        )
+    -- The `i_next_event` should be updated because if the task has been
+    -- "buried" after it was "taken" (and the task has "ttr") when the time in
+    -- `i_next_event` will be interpreted as "ttl" in `utubettl_fiber_iteration`
+    -- and the task will be deleted.
+    local task = self.space:get{id}
+    if task == nil then
+        return
     end
-    self:on_task_change(task, 'bury')
+    task = self.space:update(id, {
+            { '=', i_status, state.BURIED },
+            { '=', i_next_event, task[i_created] + task[i_ttl] }
+    })
+
+    return process_neighbour(
+        self, task:transform(i_status, 1, state.BURIED), 'bury'
+    )
 end
 
 -- unbury several tasks

t/190-work-with-ttl-buried-task.t

@@ -22,35 +22,42 @@ tnt.cfg{}
 test:test('test work with "ttl", when "bury" after "take"', function(test)
     -- Before the patch if a task has been "buried" after it was "taken"
     -- (and the task has "ttr") when the time in `i_next_event` will be
-    -- interpreted as "ttl" in `fifottl_fiber_iteration` and the task will
-    -- be deleted.
-    test:plan(3)
+    -- interpreted as "ttl" in `{fifottl,utubettl}_fiber_iteration` and
+    -- the task will be deleted.
+    local drivers = {'fifottl', 'utubettl'}
+    test:plan(3 * table.getn(drivers))
 
     local TTR = 0.2
     local TTL = 1
 
-    local driver = 'fifottl'
-    local tube = queue.create_tube('test_tube', driver, {if_not_exists = true})
-    local task = tube:put('task1', {ttl = TTL, ttr = TTR})
-
-    -- "Take" a task and "bury" it.
-    task = tube:take(0)
-    local id = task[TASK_ID]
-    tube:bury(id)
-
-    -- Check status of the task.
-    task = tube:peek(id)
-    test:is(task[TASK_STATE], state.BURIED, 'task "buried"')
-
-    -- Check status of the task after "ttr" has expired.
-    fiber.sleep(TTR * 2)
-    task = tube:peek(id)
-    test:is(task[TASK_STATE], state.BURIED, 'task is still "buried"')
-
-    -- Check status of the task after "ttl" has expired.
-    fiber.sleep(TTL * 2)
-    task, err = pcall(tube.peek, tube, id)
-    test:ok(err:match(string.format('Task %d not found', id)), 'task done')
+    for _, driver in pairs(drivers) do
+        local tube = queue.create_tube('test_tube', driver, {if_not_exists = true})
+        local task = tube:put('task1', {ttl = TTL, ttr = TTR})
+
+        -- "Take" a task and "bury" it.
+        task = tube:take(0)
+        local id = task[TASK_ID]
+        tube:bury(id)
+
+        -- Check status of the task.
+        task = tube:peek(id)
+        test:is(task[TASK_STATE], state.BURIED,
+            ('task "buried", driver: "%s"'):format(driver))
+
+        -- Check status of the task after "ttr" has expired.
+        fiber.sleep(TTR * 2)
+        task = tube:peek(id)
+        test:is(task[TASK_STATE], state.BURIED,
+            ('task is still "buried", driver: "%s"'):format(driver))
+
+        -- Check status of the task after "ttl" has expired.
+        fiber.sleep(TTL * 2)
+        ok, res = pcall(tube.peek, tube, id)
+        test:ok(res:match(string.format('Task %d not found', id)),
+            ('task done, driver: "%s"'):format(driver))
+
+        tube:drop()
+    end
 end)
 
 tnt.finish()