From 28c47ab435220d1b81870093aaf50225d7b8f05c Mon Sep 17 00:00:00 2001
From: Steffen Beyer <steffen@beyer.io>
Date: Fri, 20 Mar 2026 04:10:06 +0100
Subject: [PATCH] test/build: Stability, compatibility

---
 justfile                                      | 11 +--
 .../storage/adapters/memory/store.ex          | 76 ++++++++++++++++---
 lib/parrhesia/storage/supervisor.ex           | 10 ++-
 .../storage/adapters/memory/adapter_test.exs  |  6 ++
 4 files changed, 86 insertions(+), 17 deletions(-)

diff --git a/justfile b/justfile
index 7f06cd9..08f3dcc 100644
--- a/justfile
+++ b/justfile
@@ -1,5 +1,4 @@
 set shell := ["bash", "-euo", "pipefail", "-c"]
-set script-interpreter := ["bash", "-euo", "pipefail"]
 
 repo_root := justfile_directory()
 
@@ -12,8 +11,9 @@ help topic="":
   @cd "{{repo_root}}" && ./scripts/just_help.sh "{{topic}}"
 
 # Raw e2e harness commands.
-[script]
-e2e subcommand="help" *args:
+e2e subcommand *args:
+  #!/usr/bin/env bash
+  set -euo pipefail
   cd "{{repo_root}}"
   subcommand="{{subcommand}}"
 
@@ -40,8 +40,9 @@ e2e subcommand="help" *args:
   fi
 
 # Benchmark flows (local/cloud/history + direct relay targets).
-[script]
-bench subcommand="help" *args:
+bench subcommand *args:
+  #!/usr/bin/env bash
+  set -euo pipefail
   cd "{{repo_root}}"
   subcommand="{{subcommand}}"
 
diff --git a/lib/parrhesia/storage/adapters/memory/store.ex b/lib/parrhesia/storage/adapters/memory/store.ex
index 1a74d90..625a15b 100644
--- a/lib/parrhesia/storage/adapters/memory/store.ex
+++ b/lib/parrhesia/storage/adapters/memory/store.ex
@@ -22,7 +22,17 @@ defmodule Parrhesia.Storage.Adapters.Memory.Store do
     audit_logs: []
   }
 
-  def ensure_started, do: start_store()
+  def start_link(opts \\ []) do
+    name = Keyword.get(opts, :name, @name)
+    Agent.start_link(&init_state/0, name: name)
+  end
+
+  def ensure_started do
+    case Process.whereis(@name) do
+      pid when is_pid(pid) -> :ok
+      nil -> start_store()
+    end
+  end
 
   def put_event(event_id, event) when is_binary(event_id) and is_map(event) do
     :ok = ensure_started()
@@ -159,28 +169,72 @@ defmodule Parrhesia.Storage.Adapters.Memory.Store do
   defp normalize_reduce_result(next_acc), do: next_acc
 
   def get(fun) do
-    :ok = ensure_started()
-    Agent.get(@name, fun)
+    with_store(fn pid -> Agent.get(pid, fun) end)
   end
 
   def update(fun) do
-    :ok = ensure_started()
-    Agent.update(@name, fun)
+    with_store(fn pid -> Agent.update(pid, fun) end)
   end
 
   def get_and_update(fun) do
-    :ok = ensure_started()
-    Agent.get_and_update(@name, fun)
+    with_store(fn pid -> Agent.get_and_update(pid, fun) end)
   end
 
   defp start_store do
-    case Agent.start_link(&init_state/0, name: @name) do
-      {:ok, _pid} -> :ok
-      {:error, {:already_started, _pid}} -> :ok
-      {:error, reason} -> {:error, reason}
+    case start_link() do
+      {:ok, _pid} ->
+        :ok
+
+      {:error, {:already_started, pid}} ->
+        if Process.alive?(pid) do
+          :ok
+        else
+          wait_for_store_exit(pid)
+        end
+
+      {:error, reason} ->
+        {:error, reason}
     end
   end
 
+  defp with_store(fun, attempts \\ 2)
+
+  defp with_store(fun, attempts) when attempts > 0 do
+    :ok = ensure_started()
+
+    case Process.whereis(@name) do
+      pid when is_pid(pid) ->
+        try do
+          fun.(pid)
+        catch
+          :exit, reason ->
+            if noproc_exit?(reason) and attempts > 1 do
+              with_store(fun, attempts - 1)
+            else
+              exit(reason)
+            end
+        end
+
+      nil ->
+        with_store(fun, attempts - 1)
+    end
+  end
+
+  defp with_store(_fun, 0), do: exit(:noproc)
+
+  defp wait_for_store_exit(pid) do
+    ref = Process.monitor(pid)
+
+    receive do
+      {:DOWN, ^ref, :process, ^pid, _reason} -> start_store()
+    after
+      100 -> start_store()
+    end
+  end
+
+  defp noproc_exit?({:noproc, _details}), do: true
+  defp noproc_exit?(_reason), do: false
+
   defp init_state do
     ensure_tables_started()
 
diff --git a/lib/parrhesia/storage/supervisor.ex b/lib/parrhesia/storage/supervisor.ex
index 3e73332..adf4423 100644
--- a/lib/parrhesia/storage/supervisor.ex
+++ b/lib/parrhesia/storage/supervisor.ex
@@ -13,11 +13,19 @@ defmodule Parrhesia.Storage.Supervisor do
 
   @impl true
   def init(_init_arg) do
-    children = moderation_cache_children() ++ PostgresRepos.started_repos()
+    children =
+      memory_store_children() ++ moderation_cache_children() ++ PostgresRepos.started_repos()
 
     Supervisor.init(children, strategy: :one_for_one)
   end
 
+  defp memory_store_children do
+    case Application.get_env(:parrhesia, :storage, [])[:backend] do
+      :memory -> [Parrhesia.Storage.Adapters.Memory.Store]
+      _other -> []
+    end
+  end
+
   defp moderation_cache_children do
     if PostgresRepos.postgres_enabled?() and
          Application.get_env(:parrhesia, :moderation_cache_enabled, true) do
diff --git a/test/parrhesia/storage/adapters/memory/adapter_test.exs b/test/parrhesia/storage/adapters/memory/adapter_test.exs
index 27bbce7..e238ed8 100644
--- a/test/parrhesia/storage/adapters/memory/adapter_test.exs
+++ b/test/parrhesia/storage/adapters/memory/adapter_test.exs
@@ -6,6 +6,12 @@ defmodule Parrhesia.Storage.Adapters.Memory.AdapterTest do
   alias Parrhesia.Storage.Adapters.Memory.Events
   alias Parrhesia.Storage.Adapters.Memory.Groups
   alias Parrhesia.Storage.Adapters.Memory.Moderation
+  alias Parrhesia.Storage.Adapters.Memory.Store
+
+  setup do
+    start_supervised!(Store)
+    :ok
+  end
 
   test "memory adapter supports basic behavior contract operations" do
     event_id = String.duplicate("a", 64)