From 8df7d7d92dc04bd79319d725466ffdd4176c4d87 Mon Sep 17 00:00:00 2001
From: Dmytro Shteflyuk <kpumuk@kpumuk.info>
Date: Sat, 28 Sep 2024 20:13:14 -0400
Subject: [PATCH] Do not allow both host and hosts for proxy configuration

---
 lib/kamal/configuration/docs/proxy.yml     | 2 +-
 lib/kamal/configuration/validator/proxy.rb | 4 ++++
 test/configuration/proxy_test.rb           | 5 +++++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/lib/kamal/configuration/docs/proxy.yml b/lib/kamal/configuration/docs/proxy.yml
index 092a7f32..444e2da7 100644
--- a/lib/kamal/configuration/docs/proxy.yml
+++ b/lib/kamal/configuration/docs/proxy.yml
@@ -31,7 +31,7 @@ proxy:
   # Hosts
   #
   # The hosts that will be used to serve the app. The proxy will only route requests
-  # to this host to your app.
+  # to these hosts to your app.
   #
   # If no hosts are set, then all requests will be forwarded, except for matching
   # requests for other apps deployed on that server that do have a host set.
diff --git a/lib/kamal/configuration/validator/proxy.rb b/lib/kamal/configuration/validator/proxy.rb
index c6dbcb2d..3e2eda19 100644
--- a/lib/kamal/configuration/validator/proxy.rb
+++ b/lib/kamal/configuration/validator/proxy.rb
@@ -6,6 +6,10 @@ class Kamal::Configuration::Validator::Proxy < Kamal::Configuration::Validator
       if config["host"].blank? && config["hosts"].blank? && config["ssl"]
         error "Must set a host to enable automatic SSL"
       end
+
+      if config["host"].present? && config["hosts"].present?
+        error "Must use either 'host' or 'hosts', not both"
+      end
     end
   end
 end
diff --git a/test/configuration/proxy_test.rb b/test/configuration/proxy_test.rb
index 7772012d..1bdfaeab 100644
--- a/test/configuration/proxy_test.rb
+++ b/test/configuration/proxy_test.rb
@@ -28,6 +28,11 @@ class ConfigurationProxyTest < ActiveSupport::TestCase
     assert_raises(Kamal::ConfigurationError) { config.proxy.ssl? }
   end
 
+  test "ssl with both host and hosts" do
+    @deploy[:proxy] = { "ssl" => true, host: "example.com", hosts: [ "anotherexample.com" ] }
+    assert_raises(Kamal::ConfigurationError) { config.proxy.ssl? }
+  end
+
   test "ssl false" do
     @deploy[:proxy] = { "ssl" => false }
     assert_not config.proxy.ssl?