PHP Warning: Division by zero in class-amp-img-sanitizer.php on line 299

Hello @toengel

Thank you for the support topic, can you please send us your site data privately using AMP->Support option of the plugin and share UUID with us

Docs : Support

ampwp-2c37937f-1474-5871-856e-92cd1bf35954

Hello @toengel

Thank you for the info, but unfortunately we are unable to retrieve your PHP error log with data

Can you please send us following:
1) Page on which you are receiving notice
2) Error with all the other details (full error)
3) Anything suspicious in error log

The code retrieve the image dimensions and adjust the image based on aspect ratio, somehow it divides height with 0 width which is cause of error.

Additionally can you please check if you are using any broken image/ corrupted image on the page where you are seeing that image, which leads to failure in downloading

Hi,

I just found this line multiple times in my logs. No more information.

I cannot tell you, when this issue occurs exactly.

Toengel@Alex

I will try to investigate if corrupted images or any particular image format may return zero for image dimensions

This is the line in question: https://github.com/ampproject/amp-wp/blob/28bc1bb1ef7b4d78cdcce16d7c0ce114a1acec5e/includes/sanitizers/class-amp-img-sanitizer.php#L299

// Let height have the right aspect ratio based on the width attribute.
if ( is_numeric( $node->getAttribute( Attribute::WIDTH ) ) && isset( $dimensions['height'], $dimensions['width'] ) ) {
	$height = ( (float) $node->getAttribute( Attribute::WIDTH ) * $dimensions['height'] ) / $dimensions['width'];
}

Somehow $dimensions['width'] is 0. Fixing the symptom would be to just make sure that $dimensions['width'] > 0. I wonder if it is actually false here and it is being cast to 0. I wonder if instead of checking isset() if we should rather be checking ! empty() in this method.

The value for $dimensions['height'] is most likely coming from here: https://github.com/ampproject/amp-wp/blob/28bc1bb1ef7b4d78cdcce16d7c0ce114a1acec5e/includes/utils/class-amp-image-dimension-extractor.php#L246-L249

So perhaps wp_getimagesize() is returning a bad value?

@toengel

I have opened a github issue to prevent warning, the fix will be likely to release in next version, please follow Github issue #6968 for further updates.

I’ll mark this as resolved. Feel free to open a new support topic if you require any further assistance.