AndrewKlymchuk
Hello,
I’ve encountered a problem when using Task.async_stream/3 within tests where sandbox shared mode is enabled.
I have the following test:
defmodule MyApp.SharedModeTest do
use MyApp.DataCase, async: false
test "shared mode works" do
MyApp.Repo.transaction(fn ->
Task.async_stream(
[1],
fn id -> MyApp.Repo.get(MySchema, id) end,
timeout: :infinity
)
|> Enum.to_list()
end)
end
end
DataCase content looks as follow:
setup tags do
:ok = Sandbox.checkout(MyApp.Repo)
unless tags[:async] do
Sandbox.mode(MyApp.Repo, {:shared, self()})
end
:ok
end
It fails with the following exception:
** (EXIT from #PID<0.3878.0>) exited in: DBConnection.Holder.checkout(#PID<0.3879.0>, [log: #Function<13.86356856/1 in Ecto.Adapters.SQL.with_log/3>, source: "my_table", cast_params: [1], repo: MyApp.Repo, timeout: 15000, pool_size: 10, pool: DBConnection.Ownership, ownership_timeout: 600000, queue_target: 600000, queue_interval: 600000])
** (EXIT) shutdown: %DBConnection.ConnectionError{message: "client #PID<0.3878.0> timed out because it queued and checked out the connection for longer than 15000ms\n\nClient #PID<0.3878.0> is still using a connection from owner at location:\n\n (elixir 1.17.1) lib/task/supervised.ex:292: Task.Supervised.stream_reduce/7\n (elixir 1.17.1) lib/enum.ex:4423: Enum.reverse/1\n (elixir 1.17.1) lib/enum.ex:3748: Enum.to_list/1\n (ecto_sql 3.11.3) lib/ecto/adapters/sql.ex:1358: anonymous fn/3 in Ecto.Adapters.SQL.checkout_or_transaction/4\n (db_connection 2.6.0) lib/db_connection.ex:1710: DBConnection.run_transaction/4\n ...
Apparently, db connection isn’t shared with task process, therefore it tries to check it out, but fails because it is already checked out by test process.
If I remove transaction from the test, it works as expected:
defmodule MyApp.SharedModeTest do
use MyApp.DataCase, async: false
test "shared mode works" do
Task.async_stream(
[1],
fn id -> MyApp.Repo.get(MySchema, id) end,
timeout: :infinity
)
|> Enum.to_list()
end
end
My perception is that transaction must not affect db connection sharing among processes.
Is it a bug, or I misunderstand how it must work?
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