Strange javascript error and white screen

Can someone help understand what is this error ?
Using vaadin flow 14.3.0

Thanks for the help.

[Error]
 NotSupportedError: Cannot define multiple custom elements with the same tag name
	define
	Codice Eval (dom-module.js:168)
	eval
	../node_modules/.pnpm/registry.npmjs.org/@polymer/polymer/3.2.0/node_modules/@polymer/polymer/lib/elements/dom-module.js (vaadin-bundle-2fdede4c654f5f238490.cache.js:1243)
	__webpack_require__ (vaadin-bundle-2fdede4c654f5f238490.cache.js:20)
	Codice Eval (style-gather.js:10:101)
	eval
	../node_modules/.pnpm/registry.npmjs.org/@polymer/polymer/3.2.0/node_modules/@polymer/polymer/lib/utils/style-gather.js (vaadin-bundle-2fdede4c654f5f238490.cache.js:1615)
	__webpack_require__ (vaadin-bundle-2fdede4c654f5f238490.cache.js:20)
	Codice Eval (element-mixin.js:8:100)
	eval
	../node_modules/.pnpm/registry.npmjs.org/@polymer/polymer/3.2.0/node_modules/@polymer/polymer/lib/mixins/element-mixin.js (vaadin-bundle-2fdede4c654f5f238490.cache.js:1351)
	__webpack_require__ (vaadin-bundle-2fdede4c654f5f238490.cache.js:20)
	Codice Eval (polymer-element.js:3:106)
	eval
	../node_modules/.pnpm/registry.npmjs.org/@polymer/polymer/3.2.0/node_modules/@polymer/polymer/polymer-element.js (vaadin-bundle-2fdede4c654f5f238490.cache.js:1675)
	__webpack_require__ (vaadin-bundle-2fdede4c654f5f238490.cache.js:20)

Codice Eval
	eval
	../node_modules/@vaadin/flow-frontend/@granite-elements/ace-widget/ace-widget.js (vaadin-bundle-2fdede4c654f5f238490.cache.js:9436)
	__webpack_require__ (vaadin-bundle-2fdede4c654f5f238490.cache.js:20)
	Codice Eval
	eval
	../target/frontend/generated-flow-imports.js (vaadin-bundle-2fdede4c654f5f238490.cache.js:10188)
	__webpack_require__ (vaadin-bundle-2fdede4c654f5f238490.cache.js:20)
	Codice modulo (vaadin-bundle-2fdede4c654f5f238490.cache.js:85)
	evaluate
	moduleEvaluation
	(funzione anonima)
	promiseReactionJob

Any help ?

Thanks

This problem is hard to debug. It’s a prolem with the frontend dependencies, npm is importing 2 versions of the same component.
I’ve got the same problem when I upgraded a project in Vaadin 14.3.0.alpha1.

To debug it, you can try this: https://github.com/vaadin/flow/issues/8475

That won’t fix the issue but that will give you the duplicate element.

In my case, switching to pnpm solved my problem for the version 14.3.0.alpha1 (and 14.3.0 with npm is ok).

Jean-Christophe Gueriaud:
This problem is hard to debug. It’s a prolem with the frontend dependencies, npm is importing 2 versions of the same component.
I’ve got the same problem when I upgraded a project in Vaadin 14.3.0.alpha1.

To debug it, you can try this: https://github.com/vaadin/flow/issues/8475

That won’t fix the issue but that will give you the duplicate element.

In my case, switching to pnpm solved my problem for the version 14.3.0.alpha1 (and 14.3.0 with npm is ok).

Hi,

thanks for the support, solved cleaning the project and some cleaning to pom file.