Adding new components sometimes cause client side errors

[mstahv]

Mac, JDK 11 or 12, Vaadin 14.0.0.rc3, npm 6.8

With this procedure I can reproduce this in a deterministic way.

1. Download Spring Boot starter from vaadin.com/start
2. Import to IntelliJ
3. Run a priming Maven build (mvn install)
4. Execute Application class fron IDE
5. Navigate to localhost:8080
6. Stop execution
7. Run a clean build (mvn clean install)
8. Execute Application class fron IDE
9. Navigate to localhost:8080
10. Change the MainView, e.g. add(new DatePicker());
11. reload browser -> boom

[mehdi-vaadin]

It may be the same as #6029.

[caalador]

Works as expected with windows and rc5.
Please try it out with the upcoming rc6 and reopen ticket with more details if problem persists.

[mstahv]

Just tried it out (rc7) and it failed for me.

[Legioth]

This happens because mvn clean install will create a production bundle for you and running the project directly from the IDE will keep using that production bundle. After you have made changes to your project, the production bundle is no longer in sync with the updated Java classes -> boom.

We plan on fixing this by making it so that mvn clean install would by default no create a production bundle for you but instead only set up things for using the webpack dev server. More details in #6137.