From 3f23221aa7410da703d7164eff421edd63e944f8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@dashbit.co>
Date: Mon, 24 Jun 2024 22:43:02 +0200
Subject: [PATCH] Ensure matching escapes for nil and empty strings

Closes #444.
---
 lib/phoenix_html/engine.ex | 1 +
 test/phoenix_html_test.exs | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/lib/phoenix_html/engine.ex b/lib/phoenix_html/engine.ex
index 9da33f2c..7f801f19 100644
--- a/lib/phoenix_html/engine.ex
+++ b/lib/phoenix_html/engine.ex
@@ -16,6 +16,7 @@ defmodule Phoenix.HTML.Engine do
   """
   def encode_to_iodata!({:safe, body}), do: body
   def encode_to_iodata!(nil), do: ""
+  def encode_to_iodata!(""), do: ""
   def encode_to_iodata!(bin) when is_binary(bin), do: html_escape(bin)
   def encode_to_iodata!(list) when is_list(list), do: Phoenix.HTML.Safe.List.to_iodata(list)
   def encode_to_iodata!(other), do: Phoenix.HTML.Safe.to_iodata(other)
diff --git a/test/phoenix_html_test.exs b/test/phoenix_html_test.exs
index 913e5e9a..32f31537 100644
--- a/test/phoenix_html_test.exs
+++ b/test/phoenix_html_test.exs
@@ -36,6 +36,12 @@ defmodule Phoenix.HTMLTest do
         html_escape(~c"foo🐥")
       end
     end
+
+    test "equivalences" do
+      # Since some HTML code may compare html_escape("") with html_escape(nil),
+      # we make sure they have equivalent representations.
+      assert html_escape("") == html_escape(nil)
+    end
   end
 
   describe "attributes_escape" do