Can’t extract and set SVG dimensions

I solved it!!! The filter in fix #3 (above) wasn’t working because of the third condition of this if statement that triggers the dimension extraction and attachment:

if (is_array($image) && preg_match('/\.svg$/i', $image[0]) && $image[1] == 1)

$image[1] in the third condition is the reported width of the SVG file as WP sees it before it enters the filter. Since I know that its value, the width, is 0 (from the “zero-division error” described above) I suspected that this value needed to be changed to match it. I changed the final 1 on that if condition to a 0 and..voila! The division error went away and the image is displaying, and beautifully so I might ad!

I was able to spot this because in many forums people complain that SVGs are incorrectly getting assigned widths of 1px. This was probably the case in some versions of WP, but in my WP 4.7.2 media library, no dimension for the SVG, not even 1px is posted, as a dimension. Instead there was simply no metadata regarding dimensions in my case.

I think a flexible version of the filter would allow it to be applied if the width is 1 or 0, for people who had the 1px problem and for people like me, who had a width of 0. Below I included the fix, using $image[1] <= 1as the third condition of the if statement instead of $image[1] == 1 but I suppose you could use this, too: ( ($image[1] == 0) || ($image[1] == 1) )

The working filter

 add_filter( 'wp_get_attachment_image_src', 'fix_wp_get_attachment_image_svg', 10, 4 );  /* the hook */

 function fix_wp_get_attachment_image_svg($image, $attachment_id, $size, $icon) {
    if (is_array($image) && preg_match('/\.svg$/i', $image[0]) && $image[1] <= 1) {
        if(is_array($size)) {
            $image[1] = $size[0];
            $image[2] = $size[1];
        } elseif(($xml = simplexml_load_file($image[0])) !== false) {
            $attr = $xml->attributes();
            $viewbox = explode(' ', $attr->viewBox);
            $image[1] = isset($attr->width) && preg_match('/\d+/', $attr->width, $value) ? (int) $value[0] : (count($viewbox) == 4 ? (int) $viewbox[2] : null);
            $image[2] = isset($attr->height) && preg_match('/\d+/', $attr->height, $value) ? (int) $value[0] : (count($viewbox) == 4 ? (int) $viewbox[3] : null);
        } else {
            $image[1] = $image[2] = null;
        }
    }
    return $image;
} 

Thank you everyone for your help it was really a team effort!