From f9eeecf91415040762ed874a5708e42e0a0a73b8 Mon Sep 17 00:00:00 2001
From: v0idpwn <v0idpwn@gmail.com>
Date: Mon, 22 Apr 2024 21:03:06 -0300
Subject: [PATCH 1/3] Propagate parent process logger level to preloader

Closes https://github.com/elixir-ecto/ecto_sql/issues/602
---
 lib/ecto/repo/preloader.ex | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/lib/ecto/repo/preloader.ex b/lib/ecto/repo/preloader.ex
index 23d3902966..2df9b28eaf 100644
--- a/lib/ecto/repo/preloader.ex
+++ b/lib/ecto/repo/preloader.ex
@@ -136,9 +136,11 @@ defmodule Ecto.Repo.Preloader do
       # still necessary.
       opts = Keyword.put_new(opts, :caller, self())
       on_preloader_spawn = Keyword.get(opts, :on_preloader_spawn, fn -> :ok end)
+      parent_logger_level = Logger.get_process_level(self())
 
       preloaders
       |> Task.async_stream(fn preloader ->
+        Logger.put_process_level(self(), parent_logger_level)
         on_preloader_spawn.()
         preloader.({adapter_meta, opts})
       end, timeout: :infinity)

From 3e7d9bb73e47aa85fda93f51637a34c5301c49cf Mon Sep 17 00:00:00 2001
From: v0idpwn <v0idpwn@gmail.com>
Date: Tue, 23 Apr 2024 00:09:03 -0300
Subject: [PATCH 2/3] Alternative implementation for Elixir pre-1.15.0

---
 lib/ecto/repo/preloader.ex | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/lib/ecto/repo/preloader.ex b/lib/ecto/repo/preloader.ex
index 2df9b28eaf..2b7a780780 100644
--- a/lib/ecto/repo/preloader.ex
+++ b/lib/ecto/repo/preloader.ex
@@ -129,15 +129,29 @@ defmodule Ecto.Repo.Preloader do
   defp maybe_pmap(preloaders, _repo_name, {adapter_meta, opts}) do
     if match?([_, _ | _] , preloaders) and not adapter_meta.adapter.checked_out?(adapter_meta) and
          Keyword.get(opts, :in_parallel, true) do
+      pmap(preloaders, {adapter_meta, opts})
+    else
+      Enum.map(preloaders, &(&1.({adapter_meta, opts})))
+    end
+  end
+
+  # TODO: once we require Elixir >= v1.15.0, we can remove the alternative 
+  # function implementations
+  if Version.match?(System.version(), ">= 1.15.0") do
+    defp pmap(preloaders, {adapter_meta, opts}) do
       # We pass caller: self() so the ownership pool knows where
       # to fetch the connection from and set the proper timeouts.
       # Note while the ownership pool uses '$callers' from pdict,
       # it does not do so in automatic mode, hence this line is
       # still necessary.
       opts = Keyword.put_new(opts, :caller, self())
-      on_preloader_spawn = Keyword.get(opts, :on_preloader_spawn, fn -> :ok end)
+
+      # Additionally, we propagate the caller's logger level to
+      # the spawned tasks
       parent_logger_level = Logger.get_process_level(self())
 
+      on_preloader_spawn = Keyword.get(opts, :on_preloader_spawn, fn -> :ok end)
+
       preloaders
       |> Task.async_stream(fn preloader ->
         Logger.put_process_level(self(), parent_logger_level)
@@ -148,9 +162,23 @@ defmodule Ecto.Repo.Preloader do
         {:ok, assoc} -> assoc
         {:exit, reason} -> exit(reason)
       end)
-    else
-      Enum.map(preloaders, &(&1.({adapter_meta, opts})))
     end
+  else
+    defp pmap(preloaders, {adapter_meta, opts}) do
+      opts = Keyword.put_new(opts, :caller, self())
+      on_preloader_spawn = Keyword.get(opts, :on_preloader_spawn, fn -> :ok end)
+
+      preloaders
+      |> Task.async_stream(fn preloader ->
+        on_preloader_spawn.()
+        preloader.({adapter_meta, opts})
+      end, timeout: :infinity)
+      |> Enum.map(fn
+        {:ok, assoc} -> assoc
+        {:exit, reason} -> exit(reason)
+      end)
+    end
+
   end
 
   # Then we unpack the query results, merge them, and preload recursively

From 39237937b46d34cbf8ab357581086b277b3c704e Mon Sep 17 00:00:00 2001
From: v0idpwn <v0idpwn@gmail.com>
Date: Tue, 23 Apr 2024 00:16:46 -0300
Subject: [PATCH 3/3] Add note regarding alterantive pmap versions

---
 lib/ecto/repo/preloader.ex | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/lib/ecto/repo/preloader.ex b/lib/ecto/repo/preloader.ex
index 2b7a780780..e1f6698418 100644
--- a/lib/ecto/repo/preloader.ex
+++ b/lib/ecto/repo/preloader.ex
@@ -135,8 +135,14 @@ defmodule Ecto.Repo.Preloader do
     end
   end
 
-  # TODO: once we require Elixir >= v1.15.0, we can remove the alternative 
-  # function implementations
+  # TODO: once we require Elixir >= v1.15.0, we can remove the
+  # alternative function implementations.
+  #
+  # Elixir v1.15.0 included the `Logger.get_process_level/2` and
+  # `Logger.put_process_level` functions, which are used here
+  # to guarantee that the preloader processes inherit the parent's
+  # logger level.
+  #
   if Version.match?(System.version(), ">= 1.15.0") do
     defp pmap(preloaders, {adapter_meta, opts}) do
       # We pass caller: self() so the ownership pool knows where
@@ -178,7 +184,6 @@ defmodule Ecto.Repo.Preloader do
         {:exit, reason} -> exit(reason)
       end)
     end
-
   end
 
   # Then we unpack the query results, merge them, and preload recursively