Could not find Angular Material core theme. Most Material components may not work as expected. For more info refer to the theming guide: https://material.angular.io/guide/theming

Hi! Ciao! How Are You???

Bug, feature request, or proposal:

Could not find Angular Material core theme, although all core @include mat-core(); is included. I got 6 themes, all working except the warning.

What is the expected behavior?

No warning.

What is the current behavior?

Warning.

What are the steps to reproduce?

git clone https://github.com/patrikx3/corifeus-app-web-pages.git
cd corifeus-app-web-pages
yarn install
grunt run

See.

What is the use-case or motivation for changing an existing behavior?

Themes.

Which versions of Angular, Material, OS, browsers are affected?

Current.

Is there anything else we should know?

Nope.

[fxck]

Yeah, I'm getting this as well.

[crisbeto]

We have a marker style that we check for on load. When are you loading your theme?

It is dynamic, based on a cookie.

but i think the mat-core is loading right away.
it is in a css. so instant i think.

[crisbeto]

I can see you loading the mixins in a few places, but I couldn't find any instances of the mat-core or angular-material-theme mixins being included anywhere.

https://github.com/patrikx3/corifeus-web-material.git
The styles are there.

https://github.com/patrikx3/corifeus-web-material/blob/master/src/scss/material/_all.scss

that is a componet.
and i include here:
https://github.com/patrikx3/corifeus-app-web-pages/blob/f734270fd15d263beb4930095a90d20b7165cb42/src/angular/layout/cory-layout.scss

[crisbeto]

Alright, then it's definitely an issue with Material checking too early. We probably can't anticipate when styles are loaded without a major performance hit, but we could add a flag to disable the warnings for advanced cases like this. What do you think @jelbourn?

[willshowell]

Being able to disable the warning might help with #4056 too

[jelbourn]

@crisbeto what if we just delay the check for a few seconds? That way it will still be visible to developers by the time they open the dev tools but should be enough time to load styles for initial view.

[crisbeto]

We could, but that can still be race condition-ey. We can do something like a 5s delay if we really want to be safe.

[jelbourn]

I'd be okay with that as a simple workaround