Bug: Warning: DOMXPath::query(): Invalid expression

[ceesvanegmond]

Implementing the library I get an Symfony\Component\Debug\Exception\ ContextErrorException with the message Warning: DOMXPath::query(): Invalid expression on line 153.

Debugging this error, apparently the $expression variable on line 150 equals false.
For now I'mm using a quick fix:

if (! $expression) {
    return false;
}

This doens't seem the right solution right?
In the buildExpressionForSelector function, the $selector equals @fontface.
An exceptioninterface is being thrown with the message Expected selector, but <delimiter "@" at 0> found.. false is being returned and that's why the DOMXpath warning is thrown.

Any idea on how to fix this?

Anyhow this library is awesome 👍

[JanDC]

Hi @ceesvanegmond,

Looking at the error, it does indeed seem like the @fontface selector is not supported by DOMXPath.

I'll look into it, thank you for reporting this error 👍

[ceesvanegmond]

Hi @JanDC ,

Ah right. How can we fix this? I could to PR if you want.

[JanDC]

I haven't got a clue how to fix it without debugging it myself 😄 .
I'll look into it tonight, I hope it's not too critical for you to have it solved right away.

Of course you could debug it yourself and PR me if you've found something...

[ceesvanegmond]

@JanDC I've looked in to it, but i don't come any further when return false when the $expression is false.

[JanDC]

@ceesvanegmond

I've been looking in to it, but I can't seem to generate the same error when I add a @font-face selector. Do you mind sending me the broken css (or a snippet)?

ping @gijsroge

[JanDC]

@ceesvanegmond , I just realized the @fontface selector you referenced wasn't valid and I confused it with @font-face.

Your suggestion is therefor valid: if an expression cannot be build, we skip the related rule since it's not a valid selector.

[ceesvanegmond]

@JanDC 👍