Restrict Logger.configure on config_change callback (#10388)

The `config_change` callback is called from `application_controller` process,
which is receiving env updates on releases. `Logger.configure` does a blocking
call to the `Logger` process, which calls `Application.put_env`

This causes a crash on logger config update.

The fix is to call `Logger.configure` only for the config that have not yet
been persisted.

Author: hairyhum

lib/logger/lib/logger/app.ex

@@ -62,7 +62,9 @@ defmodule Logger.App do
 
   @doc false
   def config_change(changed, _new, _removed) do
-    Logger.configure(changed)
+    # All other config has already been persisted, we only need to
+    # update the level and reload the logger state.
+    Logger.configure(Keyword.take(changed, [:level]))
   end
 
   @doc """

lib/logger/test/logger_test.exs

@@ -647,7 +647,8 @@ defmodule LoggerTest do
     :ok = Logger.configure(level: :debug)
 
     try do
-      assert Logger.App.config_change([level: :error], [], []) === :ok
+      assert Application.put_env(:logger, :level, :error) === :ok
+      assert :application_controller.config_change(logger: [level: :debug]) === :ok
       assert Logger.level() === :error
     after
       Logger.configure(level: :debug)