Hide Add to Cart button in Woocommerce product variations for a specific attribute value

Question

In Woocommerce, I\'m trying to hide add to cart button for variations with a specific selected value for one of attributes. There are two attributes for each variation (

Answer 1

Use your slug text for term_name

add_filter( 'woocommerce_variation_is_purchasable', 'conditional_variation_is_purchasable', 20, 2 );
function conditional_variation_is_purchasable( $purchasable, $product ) {

    ## ---- Your settings ---- ##

    $taxonomy  = 'pa_size';
    $term_name =  'XL';

    ## ---- The active code ---- ##

    $found = false;

    // Loop through all product attributes in the variation
    foreach ( $product->get_variation_attributes() as $variation_attribute => $term_slug ){
        $attribute_taxonomy = str_replace('attribute_', '', $variation_attribute); // The taxonomy
        $term = get_term_by( 'slug', $term_slug, $taxonomy ); // The WP_Term object
        // Searching for attribute 'pa_size' with value 'XL'
        if($attribute_taxonomy == $taxonomy && $term->slug == $term_name ){
            $found = true;
            break;
        }
    }

    if( $found )
        $purchasable = false;

    return $purchasable;
}

Answer 2

Here is the way to make add to cart button inactive on product variations which product attribute "pa_size" with a "XL" value:

add_filter( 'woocommerce_variation_is_purchasable', 'conditional_variation_is_purchasable', 20, 2 );
function conditional_variation_is_purchasable( $purchasable, $product ) {

    ## ---- Your settings ---- ##

    $taxonomy  = 'pa_size';
    $term_name =  'XL';

    ## ---- The active code ---- ##

    $found = false;

    // Loop through all product attributes in the variation
    foreach ( $product->get_variation_attributes() as $variation_attribute => $term_slug ){
        $attribute_taxonomy = str_replace('attribute_', '', $variation_attribute); // The taxonomy
        $term = get_term_by( 'slug', $term_slug, $taxonomy ); // The WP_Term object
        // Searching for attribute 'pa_size' with value 'XL'
        if($attribute_taxonomy == $taxonomy && $term->name == $term_name ){
            $found = true;
            break;
        }
    }

    if( $found )
        $purchasable = false;

    return $purchasable;
}

Code goes in function.php file of your active child theme (or theme). Tested and works.