How can you include a theme template file from within a plugin (i.e. WooCommerce's Shop page)?

Question

I'm trying to customise WooCommerce's Shop page (called 'Products' in this instance) to include a template part from my main WordPress theme.

get_template_part() does not work. I believe that's because a plugin can't tell which files will exist in a theme so it's disabled. Alternatively, I wonder if it's because the function is being called from within the plugin directory, so it's looking in the wrong directory.

include() does not work. I get the following errors:

Warning: include(): http:// wrapper is disabled in the server configuration by allow_url_include=0 in ...\woocommerce\archive-product.php on line 52
Warning: include(.../partials/acf-flexible-layout.php): failed to open stream: no suitable wrapper could be found in ...\woocommerce\archive-product.php on line 52
Warning: include(): Failed opening '.../partials/acf-flexible-layout.php' for inclusion (include_path='.;C:\php\pear') in ...\woocommerce\archive-product.php on line 52

note: the three dots (...) in the file paths are a reference to my theme.

Something else to note is that the template part I'm trying to include reference Advanced Custom Fields associated with the Products / Shop page in WordPress.

copying the template part's code directly into the archive-product.php does not work. I'm not sure why this is.

Any help would be much appreciated.

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EDIT I have already checked How to include a file using get_template_part() in a plugin? but it doesn't seem suitable:

1. The answer chosen gives include() as a solution. I've already said this doesn't work for me.
2. It's not a plugin I'm developing. It's WooCommerce. Any updates to the plugin could delete the files I add / change.
3. I don't fully understand the other promising answer given, so I'm not able to adapt it to suit my needs (if that's even possible).

Answer 1

I have a solution to this, at least in my specific case.

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Solution

get_template_part() did work in the end, but ACF needed the ID of the post (the Shop page). When calling ACF fields from outside of the loop you need to specify a post ID.

For all of the other pages on the site where the template is being used, it knew the ID already so I didn't have to specify. Seemingly, where I was calling it from in archive-product.php was outside of the loop. If someone could clarify that, it may be helpful.

So, in archive-product.php:

<?php get_template_part( 'partials/acf', 'a-template-file' ); ?>

Then in the template file:

$post_id = '';
if ( is_shop() ) {
    $post_id = 20;  // 20 being the ID of my Shop page
} else {
    $post_id = get_the_ID();
}

if ( have_rows('flexible_content_layout', $post_id) ) {

    while ( have_rows('flexible_content_layout', $post_id) ) {

        the_row();

        // etc, etc...