Elixir 1.19: Warn on old config of :console Logger and conflicts

lib/pleroma/config/deprecation_warnings.ex

@@ -419,7 +419,52 @@ defmodule Pleroma.Config.DeprecationWarnings do
 
   @spec check_deprecated_logger_config() :: :ok | :error
   def check_deprecated_logger_config do
-    backend = if Application.get_env(:logger, :backends) do
+    mix_env = Pleroma.Config.get(:env)
+    config_file_name = "config/#{mix_env}.secret.exs"
+    config_file = File.read(config_file_name)
+
+    config_file =
+      case config_file do
+        {:ok, contents} ->
+          String.split(contents, "\n", trim: true)
+          |> Enum.reject(fn string -> String.starts_with?(string, "#") end)
+          |> Enum.join("\n")
+
+        _ ->
+          false
+      end
+
+    declared_deprecated_backend =
+      if is_binary(config_file) do
+        String.contains?(config_file, "config :logger, backends") or
+          String.contains?(config_file, "config :logger,\n  backends")
+      else
+        nil
+      end
+
+    declared_deprecated_console =
+      if is_binary(config_file) do
+        String.contains?(config_file, "config :logger, :console") or
+          String.contains?(config_file, "config :logger,\n  console")
+      else
+        nil
+      end
+
+    # We can't use Application.get_env/3, because by default default_formatter is populated
+    declared_new_console =
+      if is_binary(config_file) do
+        String.contains?(config_file, "config :logger, :default_handler") or
+          String.contains?(config_file, "config :logger,\n  :default_handler") or
+          String.contains?(config_file, "config :logger, :default_formatter") or
+          String.contains?(config_file, "config :logger,\n  :default_formatter")
+      else
+        nil
+      end
+
+    use_new_backend_config = Pleroma.Config.get([:logger, :backends])
+
+    backend =
+      if declared_deprecated_backend do
         Logger.warning("""
         !!!DEPRECATION WARNING!!!
         Your configuration is using deprecated syntax for configuring backends of Elixir's logger.
@@ -437,7 +482,8 @@ defmodule Pleroma.Config.DeprecationWarnings do
         false
       end
 
-    console = if Application.get_env(:logger, :console) do
+    console =
+      if declared_deprecated_console do
         Logger.warning("""
         !!!DEPRECATION WARNING!!!
         Your configuration is using deprecated syntax for configuring logging to console.
@@ -455,6 +501,20 @@ defmodule Pleroma.Config.DeprecationWarnings do
         false
       end
 
-    if backend or console, do: :error, else: :ok
+    conflict =
+      if (!is_nil(use_new_backend_config) and declared_deprecated_backend) or
+           (declared_new_console and declared_deprecated_console) do
+        Logger.warning("""
+        !!!CONFIGURATION CONFLICT!!!
+        Pleroma has detected that both the deprecated way of configuring Logger and the new way are defined in your configuration.
+        Delete the deprecated configuration syntax.
+        """)
+
+        true
+      else
+        false
+      end
+
+    if backend or console or conflict, do: :error, else: :ok
   end
 end

test/pleroma/config/deprecation_warnings_test.exs

@@ -401,7 +401,8 @@ defmodule Pleroma.Config.DeprecationWarningsTest do
     end
 
     test "warns on deprecated syntax" do
-      log = capture_log(fn ->
+      log =
+        capture_log(fn ->
           Pleroma.Config.DeprecationWarnings.check_deprecated_logger_config()
         end)