Mateusz Kwiatkowski

As I mentioned on Slack while doing using a @Async new thread is losing context by default. We are getting locale info from LocaleContextHolder while translating messages so this was causing missing translations for email notifications. Here is a GitHub issue regarding this problem: https://github.com/spring-projects/spring-boot/issues/14079
I think we are safe to use "dispatcherServlet.setThreadContextInheritable(true);" but Javadoc says:
/**

• Set whether to expose the LocaleContext and RequestAttributes as inheritable
• for child threads (using an
  Unknown macro: {@link java.lang.InheritableThreadLocal}

  ).

• <p>Default is "false", to avoid side effects on spawned background threads.
• Switch this to "true" to enable inheritance for custom child threads which
• are spawned during request processing and only used for this request
• (that is, ending after their initial task, without reuse of the thread).
• <p><b>WARNING:</b> Do not use inheritance for child threads if you are
• accessing a thread pool which is configured to potentially add new threads
• on demand (e.g. a JDK
  Unknown macro: {@link java.util.concurrent.ThreadPoolExecutor}

  ),

• since this will expose the inherited context to such a pooled thread.
  */
  Alternatively, we could retrieve locale before starting a new thread and passing it there, but it would require more work.
  I would be nice if we could agree on a solution quickly as it is blocking release and I still need to include it in patch release for Angola. Also, I would need to include those changes in other services that are sending notifications asynchronously.