Live Reload trouble with 14.4

Found that by updating to 14.4 Live Reload stopped working. No widget appears in the browser, no error messages client or server side, and changes are not reflected in the running application. I didn’t see anything in the release notes on this topic.

I typically use HotswapAgent, but find the same problem when using Spring Boot DevTools. Is anyone else finding the same thing?

Ted: one change in 14.4 vs 14.3 is that the live reload widget is in a separate Webpack bundle. Do you happen to have some customized Webpack configuration in your project? To figure out whether the problem is on the server or client side you could check if a <vaadin-devmode-gizmo> element is added under <body> when you load the page in the browser. If it is, then the problem is most likely the custom element not being registered; if not, the issue may be on the server side.

No changes to the webpack config.

Your questions were enough to get me to a resolution: I had to rebuild the webpack.generated.js file before it would start working.

Resolution tips
In cases of an existing app making use of the vaadin maven plugin: running the vaadin:prepare-frontend goal will fix this.

In cases of an existing app that does not make use of that plugin (as is the case with a spring initilizr based vaadin app), I’m not sure what mechanism creates the webpack.generated.js file, but if you just delete it then the file will be re-generated on launch with the appropriate configuration of the vaadin-devmode-gizmo.

Hello! Can confirm that widget is not working for 14.4.x if you change Vaadin version in the base-starter-spring-gradle

https://github.com/vaadin/base-starter-spring-gradle/blob/v14/build.gradle#L19

Related issue https://github.com/vaadin/base-starter-spring-gradle/issues/5

I just posted something about it https://vaadin.com/forum/thread/18467775/java-live-reload-unavailable

But now… after a few clean and build later, it started to work