From 0584a3345e9d7ecd84494abc6ba7971309b5a338 Mon Sep 17 00:00:00 2001
From: schneems <richard.schneeman@gmail.com>
Date: Wed, 2 Aug 2017 14:28:39 -0500
Subject: [PATCH] [close #1327] Fix double port bind in Rails

The "default" configuration puma level is initialized with a "binds" of `tcp://0.0.0.0:9292`. Puma is designed to be able to bind to multiple ports.

When a `:port` is sent from Rails along with an empty `user_supplied_options` then the port is treated as a "default". This is merged in with the system defaults, and then later converted into a "binds" via calling `config.port` in the `set_host_port_to_config` method.

The bug comes due to the "level" of the configuration. Since both are being set on the same "level" the `port` call does not over-write the existing binds but instead prepends to the array. We can fix by ensuring that any binds in a given "level" are empty before setting it.
---
 lib/puma/dsl.rb           |  4 ++++
 lib/rack/handler/puma.rb  |  2 ++
 test/test_rack_handler.rb | 10 ++++++++++
 3 files changed, 16 insertions(+)

diff --git a/lib/puma/dsl.rb b/lib/puma/dsl.rb
index eca8fe71f8..e2e142246c 100644
--- a/lib/puma/dsl.rb
+++ b/lib/puma/dsl.rb
@@ -118,6 +118,10 @@ def bind(url)
       @options[:binds] << url
     end
 
+    def clear_binds!
+      @options[:binds] = []
+    end
+
     # Define the TCP port to bind to. Use +bind+ for more advanced options.
     #
     def port(port, host=nil)
diff --git a/lib/rack/handler/puma.rb b/lib/rack/handler/puma.rb
index ef1a2a7f6a..83b757c24a 100644
--- a/lib/rack/handler/puma.rb
+++ b/lib/rack/handler/puma.rb
@@ -84,6 +84,8 @@ def self.valid_options
       end
     private
       def self.set_host_port_to_config(host, port, config)
+        config.clear_binds! if host || port
+
         if host && (host[0,1] == '.' || host[0,1] == '/')
           config.bind "unix://#{host}"
         elsif host && host =~ /^ssl:\/\//
diff --git a/test/test_rack_handler.rb b/test/test_rack_handler.rb
index 73809cb12d..fa9e75a638 100644
--- a/test/test_rack_handler.rb
+++ b/test/test_rack_handler.rb
@@ -153,6 +153,16 @@ def test_config_wins_over_default
     end
   end
 
+  def test_user_port_wins_over_default_when_user_supplied_is_blank
+    user_port = 5001
+    @options[:user_supplied_options] = []
+    @options[:Port] = user_port
+    conf = Rack::Handler::Puma.config(->{}, @options)
+    conf.load
+
+    assert_equal ["tcp://0.0.0.0:#{user_port}"], conf.options[:binds]
+  end
+
   def test_user_port_wins_over_default
     user_port = 5001
     @options[:Port] = user_port