From f44362b1400f4ce38887c0b72e334ea145b4a365 Mon Sep 17 00:00:00 2001
From: Akshay Birajdar <akshaybirajdar05@gmail.com>
Date: Sat, 3 Sep 2022 03:02:24 +0530
Subject: [PATCH] Show BCC recipients in mailer preview

---
 railties/CHANGELOG.md                         |  4 +++
 .../templates/rails/mailers/email.html.erb    |  5 ++++
 .../test/application/mailer_previews_test.rb  | 30 +++++++++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/railties/CHANGELOG.md b/railties/CHANGELOG.md
index ce539e6f66ab8..32d06d6bd55fa 100644
--- a/railties/CHANGELOG.md
+++ b/railties/CHANGELOG.md
@@ -1,3 +1,7 @@
+*   Show BCC recipients when present in Action Mailer previews.
+
+    *Akshay Birajdar*
+
 *   Extend `routes --grep` to also filter routes by matching against path.
 
     Example:
diff --git a/railties/lib/rails/templates/rails/mailers/email.html.erb b/railties/lib/rails/templates/rails/mailers/email.html.erb
index 59c2f283df01a..0c5ff765d4f7e 100644
--- a/railties/lib/rails/templates/rails/mailers/email.html.erb
+++ b/railties/lib/rails/templates/rails/mailers/email.html.erb
@@ -80,6 +80,11 @@
       <dd id="cc"><%= @email.header['cc'] %></dd>
     <% end %>
 
+    <% if @email.bcc %>
+      <dt>BCC:</dt>
+      <dd id="bcc"><%= @email.header['bcc'] %></dd>
+    <% end %>
+
     <dt>Date:</dt>
     <dd id="date"><%= Time.current.rfc2822 %></dd>
 
diff --git a/railties/test/application/mailer_previews_test.rb b/railties/test/application/mailer_previews_test.rb
index 4651120b23ab4..354bf91182400 100644
--- a/railties/test/application/mailer_previews_test.rb
+++ b/railties/test/application/mailer_previews_test.rb
@@ -877,6 +877,36 @@ def foo
       assert_match "<title>Mailer Preview for notifier#foo</title>", last_response.body
     end
 
+    test "mailer preview sender tags" do
+      mailer "notifier", <<-RUBY
+        class Notifier < ActionMailer::Base
+          default from: "from@example.com"
+          def foo
+            mail to: "to@example.org", cc: "cc@example.com", bcc: "bcc@example.com"
+          end
+        end
+      RUBY
+
+      text_template "notifier/foo", <<-RUBY
+        Hello, World!
+      RUBY
+
+      mailer_preview "notifier", <<-RUBY
+        class NotifierPreview < ActionMailer::Preview
+          def foo
+            Notifier.foo
+          end
+        end
+      RUBY
+
+      app("development")
+
+      get "/rails/mailers/notifier/foo"
+      assert_match "<dd id=\"to\">to@example.org</dd>", last_response.body
+      assert_match "<dd id=\"cc\">cc@example.com</dd>", last_response.body
+      assert_match "<dd id=\"bcc\">bcc@example.com</dd>", last_response.body
+    end
+
     private
       def build_app
         super