Set the default for mailer depending on the value of ecto

installer/lib/mix/tasks/phx.new.ecto.ex

@@ -59,6 +59,10 @@ defmodule Mix.Tasks.Phx.New.Ecto do
       Mix.raise("The ecto task can only be run within an umbrella's apps directory")
     end
 
-    Mix.Tasks.Phx.New.run(args ++ ["--no-assets", "--ecto"], Phx.New.Ecto, :app_path)
+    Mix.Tasks.Phx.New.run(
+      args ++ ["--no-assets", "--ecto"],
+      Phx.New.Ecto,
+      :app_path
+    )
   end
 end

installer/lib/phx_new/generator.ex

@@ -176,7 +176,7 @@ defmodule Phx.New.Generator do
     assets = Keyword.get(opts, :assets, true)
     esbuild = Keyword.get(opts, :esbuild, assets)
     tailwind = Keyword.get(opts, :tailwind, assets)
-    mailer = Keyword.get(opts, :mailer, true)
+    mailer = Keyword.get(opts, :mailer, !ecto)
     dev = Keyword.get(opts, :dev, false)
     phoenix_path = phoenix_path(project, dev, false)
     phoenix_path_umbrella_root = phoenix_path(project, dev, true)
@@ -188,7 +188,8 @@ defmodule Phx.New.Generator do
     {adapter_app, adapter_module, adapter_config} =
       get_ecto_adapter(db, String.downcase(project.app), project.app_mod)
 
-    {web_adapter_app, web_adapter_vsn, web_adapter_module, web_adapter_docs} = get_web_adapter(web_adapter)
+    {web_adapter_app, web_adapter_vsn, web_adapter_module, web_adapter_docs} =
+      get_web_adapter(web_adapter)
 
     pubsub_server = get_pubsub_server(project.app_mod)
 
@@ -304,8 +305,16 @@ defmodule Phx.New.Generator do
     Mix.raise("Unknown database #{inspect(db)}")
   end
 
-  defp get_web_adapter("cowboy"), do: {:plug_cowboy, "~> 2.7", Phoenix.Endpoint.Cowboy2Adapter, "https://hexdocs.pm/plug_cowboy/Plug.Cowboy.html"}
-  defp get_web_adapter("bandit"), do: {:bandit, "~> 1.2", Bandit.PhoenixAdapter, "https://hexdocs.pm/bandit/Bandit.html#t:options/0"}
+  defp get_web_adapter("cowboy"),
+    do:
+      {:plug_cowboy, "~> 2.7", Phoenix.Endpoint.Cowboy2Adapter,
+       "https://hexdocs.pm/plug_cowboy/Plug.Cowboy.html"}
+
+  defp get_web_adapter("bandit"),
+    do:
+      {:bandit, "~> 1.2", Bandit.PhoenixAdapter,
+       "https://hexdocs.pm/bandit/Bandit.html#t:options/0"}
+
   defp get_web_adapter(other), do: Mix.raise("Unknown web adapter #{inspect(other)}")
 
   defp fs_db_config(app, module) do