anotherpit
Nested grafts + Oban.Pro.Workflow.status = Infinite recursion
A graft inside another graft causes Oban.Pro.Workflow.status to recurse forever. oban_pro 1.7.5
defmodule App.NestedGraftRepro.Test do
# Minimal, self-contained reproduction of an Oban.Pro nested-graft bug (oban_pro 1.7.5).
#
# A graft that executes while its own job's `workflow_id` is already "grafted_"-prefixed
# (i.e. a graft nested inside a grafted workflow) produces a sub-job whose
# `workflow_id == sup_workflow_id`. `Oban.Pro.Workflow.status/1` walks sub-workflows via
# `sup_workflow_id -> workflow_id` with no visited-set, so that self-edge makes
# `expand_status` recurse forever (here: child process killed at max_heap).
#
# Topology:
# - W -> add_graft(:outer);
# - outer grafts a workflow containing add_graft(:inner);
# - inner grafts a leaf -> leaf.workflow_id == leaf.sup_workflow_id.
use ExUnit.Case, async: false
# `prefix: "sunrise"` matches this app's Oban schema; upstream you'd drop it (default "public").
use Oban.Pro.Testing, repo: App.Repo
import Ecto.Query
setup do
pid = Ecto.Adapters.SQL.Sandbox.start_owner!(App.Repo, shared: true)
on_exit(fn -> Ecto.Adapters.SQL.Sandbox.stop_owner(pid) end)
:ok
end
defmodule Leaf do
use Oban.Pro.Worker, queue: :general, max_attempts: 1
@impl Oban.Pro.Worker
def process(%Oban.Job{}), do: :ok
end
defmodule InnerGrafter do
use Oban.Pro.Worker, queue: :general, max_attempts: 1
@impl Oban.Pro.Worker
def process(%Oban.Job{}) do
Oban.Pro.Workflow.new()
|> Oban.Pro.Workflow.add(:leaf, Leaf.new(%{}))
|> Oban.Pro.Workflow.apply_graft()
|> Oban.insert_all()
:ok
end
end
defmodule OuterGrafter do
use Oban.Pro.Worker, queue: :general, max_attempts: 1
@impl Oban.Pro.Worker
def process(%Oban.Job{}) do
# Graft a workflow that itself contains a graft point -> nesting.
Oban.Pro.Workflow.new()
|> Oban.Pro.Workflow.add_graft(:inner, InnerGrafter.new(%{}))
|> Oban.Pro.Workflow.apply_graft()
|> Oban.insert_all()
:ok
end
end
test "nested graft produces workflow_id == sup_workflow_id, and status/1 never terminates" do
Oban.Testing.with_testing_mode(:manual, fn ->
Oban.Pro.Workflow.new()
|> Oban.Pro.Workflow.add_graft(:outer, OuterGrafter.new(%{}))
|> Oban.insert_all()
# Recursive drain (default) runs the dynamically-grafted jobs as they're inserted.
drain_jobs(queue: :general, with_safety: true)
jobs =
from(j in Oban.Job,
select: %{
name: fragment("?->>'name'", j.meta),
wid: fragment("?->>'workflow_id'", j.meta),
sup: fragment("?->>'sup_workflow_id'", j.meta)
}
)
|> App.Repo.all()
for j <- jobs, do: IO.puts("JOB #{j.name} wid=#{j.wid} sup=#{j.sup}")
# 1. The broken state: a job whose workflow_id == its own sup_workflow_id.
selfloop = Enum.find(jobs, fn j -> not is_nil(j.sup) and j.wid == j.sup end)
assert selfloop, "expected a workflow_id == sup_workflow_id self-loop job, found none"
IO.puts("SELF-LOOP NODE: name=#{selfloop.name} wid=#{selfloop.wid} sup=#{selfloop.sup}")
# 2. status/1 on that workflow never returns (infinite expand_status recursion).
# Run it in a heap-capped child so the test process survives.
parent = self()
{pid, ref} =
:erlang.spawn_opt(
fn ->
result = Oban.Pro.Workflow.status(selfloop.wid)
send(parent, {:returned, result})
end,
[:monitor, {:max_heap_size, %{size: 2_000_000, kill: true, error_logger: false}}]
)
outcome =
receive do
{:returned, _} -> :returned
{:DOWN, ^ref, :process, ^pid, reason} -> {:died, reason}
after
8_000 ->
Process.exit(pid, :kill)
:timeout
end
IO.puts("status/1 outcome: #{inspect(outcome)}")
refute outcome == :returned,
"status/1 returned — infinite recursion NOT reproduced (bug may be fixed)"
end)
end
end
Trending in Troubleshooting
I tried to run the first LLM example “Your first LLM agent” in LiveBook. Firstly I got a weird Setup block:
Mix.install([
{{mix_dep:ji...
New
Well, after getting tired of using prints to debug, I’ve decided to setup the debugger. After setting the launch as this:
{
"configu...
New
I am trying to build a container for a new Phoenix app that I want to deploy in our kubernetes cluster. The container blows up when it ...
New
or put another way, can I run a chunked worker on a queue which has no global limit set?
New
Other Trending Topics
Hey, I’m Jesse and I’m the main contributor behind Dexter, a full-featured, lightning-fast Elixir LSP optimized for large codebases. It s...
New
Beam Bots (or just BB for short) is a framework for building fault-tolerant robotics applications in Elixir using familiar OTP patterns. ...
New
Hello everyone. After busy few months I am happy to announce v0.1.0 of Emerge & Solve.
They are GUI (Emerge) and State management (S...
New
Emily is an Elixir library that runs Nx computations on Apple’s MLX. Install it as the default Nx backend and Nx, defn, Axon, Nx.Serving,...
New
I just stumbled on a newly redesigned elixir-lang.org. :tada: It looks like @Software_Mansion did the work, and I think it is generally a...
New
@hugobarauna and I (Alex Koutmos) have been hard at work on writing a book on Nerves that takes you from simply blinking LEDs to building...
New
Categories:
Sub Categories:
Forums
Popular Tags
- #ecto
- #liveview
- #troubleshooting
- #learning-elixir
- #deployment
- #library
- #erlang
- #testing
- #genserver
- #mix
- #absinthe
- #remote-other
- #otp
- #plug
- #how-to-question
- #macros
- #postgres
- #channels
- #elixirconf
- #exunit
- #discussion
- #code-sync
- #javascript
- #podcasts
- #onsite
- #dialyzer
- #docker
- #authentication
- #umbrella
- #full-time-contract
- #podcasts-by-brainlid
- #ecto-query
- #elixir-ls
- #phoenix_html
- #iex
- #blog-post
- #graphql
- #genstage
- #ai
- #elixirconf-us
- #websockets
- #supervisor
- #advent-of-code
- #distillery
- #processes
- #api
- #forms
- #metaprogramming
- #hex
- #performance










First Post!
sorenone
Welcome
@anotherpit,
Thanks for catching a strange edge case and giving us the report. It’s fixed and ready for the next patch release.