EventHandlerUI fails in Safari

[SomeoneToIgnore]

Launch test-root-context jetty in flow, open
http://localhost:8888/run/com.vaadin.flow.uitest.ui.template.EventHandlerUI

Expected: a view with elements
Actual: empty page, errors in browser and server consoles.

May be related to #1215

[caalador]

The problem has something to do with the <link rel="import" href="/bower_components/polymer/polymer.html">

for some reason this leads Safari to try getting the polymer html imports from:
/run/lib/legacy/legacy-element-mixin.html instead of the correct:
/bower_components/polymer/lib/legacy/legacy-element-mixin.html
But when actually clicking the import in inspector after failing load it resolves correctly and loads the file.

Moving the import to a HtmImport in the template file fixes this problem
@HtmlImport("/bower_components/polymer/polymer.html")

Having or not having the <base href="."> didn't change the behaviour.

[Legioth]

It would still be preferable to have those kinds of imports from inside template files instead of as @HtmlImport from the java side.

Might work with a relative path for the import URL instead of an absolute one, e.g. <link rel="import" href="bower_components/polymer/polymer.html">.

[caalador]

The problem would seem to be somewhere in how the tests pacakge is setup and built as the polymer demos work fine.

[SomeoneToIgnore]

I've failed to understand the root cause of the problem.
One more addition is that it's not connected with servlet implementation, since I've replaced UI with View (that has different url and servlet responsible for loading) and the error is still the same: Safari tries to get the resources via http://localhost:8888/view/lib/... url

I've went even further and copy-pasted the code to HelloWorld and it runs normally.
I suppose, the problem is in one of the pom.xml: this can be either jetty or frontend plugin issues.

[Legioth]

Seems to be caused by a bug in the polyfill, reported as https://github.com/webcomponents/html-imports/issues/62.

We can work around this by not using an absolute URL for loading polymer.html.

[Legioth]

Bugfix included in 1.0.2 of webcomponetnsjs.

[Haprog]

Looking latest comments by @Legioth should this issue be closed?

[Legioth]

Should be verified that it's actually fixed.

[SomeoneToIgnore]

The correct link now is : http://localhost:8888/view/com.vaadin.flow.uitest.ui.template.EventHandlerView

Works for me and Safari Version 11.0 (12604.1.38.1.7)