From 87cb223a6a4c7f266a61b28fbffd3039f39befcd Mon Sep 17 00:00:00 2001
From: Ryota Kinukawa <kinukawa@tombo-works.com>
Date: Sun, 21 Jul 2024 14:37:05 +0900
Subject: [PATCH] Add `false` value to disable `watchers`

This is useful to override `watchers`
---
 lib/phoenix/endpoint.ex                   |  2 ++
 lib/phoenix/endpoint/supervisor.ex        |  4 +++-
 test/phoenix/endpoint/supervisor_test.exs | 10 ++++++++++
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/lib/phoenix/endpoint.ex b/lib/phoenix/endpoint.ex
index 346a4d84a4..465420ac29 100644
--- a/lib/phoenix/endpoint.ex
+++ b/lib/phoenix/endpoint.ex
@@ -181,6 +181,8 @@ defmodule Phoenix.Endpoint do
 
           [another: {Mod, :fun, [arg1, arg2]}]
 
+      When `false`, watchers can be disabled.
+
     * `:force_watchers` - when `true`, forces your watchers to start
       even when the `:server` option is set to `false`.
 
diff --git a/lib/phoenix/endpoint/supervisor.ex b/lib/phoenix/endpoint/supervisor.ex
index 253db8c9cb..5ee904dcb7 100644
--- a/lib/phoenix/endpoint/supervisor.ex
+++ b/lib/phoenix/endpoint/supervisor.ex
@@ -161,8 +161,10 @@ defmodule Phoenix.Endpoint.Supervisor do
   end
 
   defp watcher_children(_mod, conf, server?) do
+    watchers = conf[:watchers] || []
+
     if server? || conf[:force_watchers] do
-      Enum.map(conf[:watchers], &{Phoenix.Endpoint.Watcher, &1})
+      Enum.map(watchers, &{Phoenix.Endpoint.Watcher, &1})
     else
       []
     end
diff --git a/test/phoenix/endpoint/supervisor_test.exs b/test/phoenix/endpoint/supervisor_test.exs
index ca2f028bb1..235c5c0be4 100644
--- a/test/phoenix/endpoint/supervisor_test.exs
+++ b/test/phoenix/endpoint/supervisor_test.exs
@@ -145,6 +145,16 @@ defmodule Phoenix.Endpoint.SupervisorTest do
              end)
     end
 
+    test "init/1 doesn't start watchers when `:server` config is true and `:watchers` is false" do
+      Application.put_env(:phoenix, WatchersEndpoint, server: true, watchers: false)
+      {:ok, {_, children}} = Supervisor.init({:phoenix, WatchersEndpoint, []})
+
+      refute Enum.any?(children, fn
+               %{start: {Phoenix.Endpoint.Watcher, :start_link, _config}} -> true
+               _ -> false
+             end)
+    end
+
     test "init/1 doesn't start watchers when `:server` config is false" do
       Application.put_env(:phoenix, WatchersEndpoint, server: false, watchers: @watchers)
       {:ok, {_, children}} = Supervisor.init({:phoenix, WatchersEndpoint, []})