Preserve BUNDLE_GEMFILE and add a test for it

History.md

@@ -10,6 +10,7 @@
 * Bugfixes
   * Your bugfix goes here (#Github Number)
   * Windows update extconf.rb for use with ssp and varied Ruby/MSYS2 combinations (#2069)
+  * Preserve `BUNDLE_GEMFILE` env var on restart (#1893)
 
 * Refactor
   * Remove unused loader argument from Plugin initializer (#2095)

lib/puma/launcher.rb

@@ -297,8 +297,10 @@ def prune_bundler
 
       log '* Pruning Bundler environment'
       home = ENV['GEM_HOME']
+      bundle_gemfile = ENV['BUNDLE_GEMFILE']
       Bundler.with_clean_env do
         ENV['GEM_HOME'] = home
+        ENV['BUNDLE_GEMFILE'] = bundle_gemfile
         ENV['PUMA_BUNDLER_PRUNED'] = '1'
         args = [Gem.ruby, puma_wild_location, '-I', dirs.join(':'), deps.join(',')] + @original_argv
         # Ruby 2.0+ defaults to true which breaks socket activation

test/bundle_preservation_test/.gitignore

@@ -0,0 +1 @@
+Gemfile.bundle_env_preservation_test.lock

test/bundle_preservation_test/Gemfile.bundle_env_preservation_test

@@ -0,0 +1 @@
+gem 'puma', path: '../..'

test/bundle_preservation_test/config.ru

@@ -0,0 +1 @@
+run lambda { |env| [200, {'Content-Type'=>'text/plain'}, [ENV['BUNDLE_GEMFILE'].inspect]] }

test/helpers/integration.rb

@@ -75,14 +75,24 @@ def restart_server_and_listen(argv)
   end
 
   # reuses an existing connection to make sure that works
-  def restart_server(connection)
+  def restart_server(connection, log: false)
     Process.kill :USR2, @pid
     connection.write "GET / HTTP/1.1\r\n\r\n" # trigger it to start by sending a new request
-    wait_for_server_to_boot
+    wait_for_server_to_boot(log: log)
   end
 
-  def wait_for_server_to_boot
-    true while @server.gets !~ /Ctrl-C/ # wait for server to say it booted
+  # wait for server to say it booted
+  def wait_for_server_to_boot(log: false)
+    if log
+      puts "Waiting for server to boot..."
+      begin
+        line = @server.gets
+        puts line if line && line.strip != ''
+      end while line !~ /Ctrl-C/
+      puts "Server booted!"
+    else
+      true while @server.gets !~ /Ctrl-C/
+    end
   end
 
   def connect(path = nil, unix: false)

test/test_preserve_bundler_env.rb

@@ -0,0 +1,35 @@
+require_relative "helper"
+require_relative "helpers/integration"
+
+class TestPreserveBundlerEnv < TestIntegration
+  def setup
+    skip NO_FORK_MSG unless HAS_FORK
+    super
+  end
+
+  # It does not wipe out BUNDLE_GEMFILE et al
+  def test_usr2_restart_preserves_bundler_environment
+    skip_unless_signal_exist? :USR2
+
+    @tcp_port = UniquePort.call
+    env = {
+      # Intentionally set this to something we wish to keep intact on restarts
+      "BUNDLE_GEMFILE" => "Gemfile.bundle_env_preservation_test",
+      # Don't allow our (rake test's) original env to interfere with the child process
+      "BUNDLER_ORIG_BUNDLE_GEMFILE" => nil
+    }
+    # Must use `bundle exec puma` here, because otherwise Bundler may not be defined, which is required to trigger the bug
+    cmd = "bundle exec puma -q -w 1 --prune-bundler -b tcp://#{HOST}:#{@tcp_port}"
+    Dir.chdir(File.expand_path("bundle_preservation_test", __dir__)) do
+      @server = IO.popen(env, cmd.split, "r")
+    end
+    wait_for_server_to_boot
+    @pid = @server.pid
+    connection = connect
+    initial_reply = read_body(connection)
+    assert_match("Gemfile.bundle_env_preservation_test", initial_reply)
+    restart_server connection
+    new_reply = read_body(connection)
+    assert_match("Gemfile.bundle_env_preservation_test", new_reply)
+  end
+end