Protect the global environment

exe/diversipub

@@ -12,6 +12,36 @@ rescue LoadError
   require gem_name
 end
 
+# Clean common ENVs
+ENV.delete 'APP_ENV'
+ENV.delete 'RACK_ENV'
+ENV.delete 'RAILS_ENV'
+
+# Clean Puma ENVs
+ENV.delete 'LISTEN_FDS'
+ENV.delete 'LISTEN_PID'
+ENV.delete 'MAX_THREADS'
+ENV.delete 'MIN_THREADS'
+ENV.delete 'NOTIFY_SOCKET'
+ENV.delete 'PUMA_BUNDLER_PRUNED'
+ENV.delete 'PUMA_DEBUG'
+ENV.delete 'PUMA_LOG_CONFIG'
+ENV.delete 'PUMA_MAX_THREADS'
+ENV.delete 'PUMA_MIN_THREADS'
+ENV.delete 'SCRIPT_NAME'
+ENV.delete 'WATCHDOG_PID'
+ENV.delete 'WATCHDOG_USEC'
+ENV.delete 'WEB_CONCURRENCY'
+
+# Freeze well-known constants
+ARGV.each(&:freeze).freeze
+ENV.each_key(&:freeze).each_value(&:freeze) # ENV itself can't be frozen
+
+# Freeze well-known globals
+$ARGV&.each(&:freeze).freeze # $ARGV is nil sometimes
+$LOAD_PATH.each(&:freeze).freeze
+
+# Non-buffered output
 $stdout.sync = true
 $stderr.sync = true