Checking for empty Arrays

To Daniel:

Google Fonts doesn’t always return a font-subset or variant.
To prevent the plugin to break, make sure to verify the array_merge function can be performed by checking if the array $font[‘variant’] $ $font[‘substes’] are set.
The following code is a correction to prevent the breaking of this plug-in for certain fonts from Google:

file: google_font_selector-v4.php

line 92 onwards:

if(!empty( $font['variants'] )) {
				    $fontlist[$font['font']]['variants'] = array_merge( $fontlist[$font['font']]['variants'], $font['variants'] );
}
if(!empty( $font['subsets'] )) {
				    $fontlist[$font['font']]['subsets'] = array_merge( $fontlist[$font['font']]['subsets'], $font['subsets'] );
}

Hope to have contributed accordingly!
:))

My best,

Oscar

https://wordpress.org/plugins/acf-google-font-selector-field/