Overriding Attributes values in Shortcode Plugins

Try not to use capital letters in the shortcode attributes, use for example

[wi_form product_name="php" product_price="888" ]

where:

add_shortcode( 'wi_form' , 'wi_form_func' );

function wi_form_func($input) {
    extract(shortcode_atts( array(
        'product_name'  => 'Java',
        'product_price' => 1000
    ), $input));
    return $product_name . esc_attr( $product_price );
}

or this:

add_shortcode( 'wi_form' , 'wi_form_func' );

function wi_form_func($input) {
    $input = shortcode_atts( array(
        'product_name'  => 'Java',
        'product_price' => 1000
    ), $input );
    return $input['product_name'] . esc_attr( $input['product_price'] );
}

if you don’t want to use extract:

Update:

The shortcode attributes go through strtolower() in the shortcode_parse_atts() function that retrieves them from the shortcode tag (see here).