fix update phased restart symlink folder

lib/puma/launcher.rb

@@ -165,6 +165,13 @@ def phased_restart
         log "* phased-restart called but not available, restarting normally."
         return restart
       end
+
+      if @options.file_options[:tag].nil?
+        dir = File.realdirpath(@restart_dir)
+        @options[:tag] = File.basename(dir)
+        set_process_title
+      end
+
       true
     end
 

test/test_worker_gem_independence.rb

@@ -112,10 +112,13 @@ def change_gem_version_during_phased_restart(old_app_dir:,
         silent_and_checked_system_command("bundle install")
       end
     end
+
+    verify_process_tag(@server.pid, File.basename(old_app_dir))
     start_phased_restart
 
     connection = connect
     new_reply = read_body(connection)
+    verify_process_tag(@server.pid, File.basename(new_app_dir))
     assert_equal new_version, new_reply
   end
 
@@ -142,4 +145,10 @@ def with_unbundled_env
       Bundler.with_unbundled_env { yield }
     end
   end
+
+  def verify_process_tag(pid, tag)
+    cmd = "ps aux | grep #{pid}"
+    io = IO.popen cmd, 'r'
+    assert io.read.include? tag
+  end
 end