Invisible 'add to cart' button

Have a look in your theme’s functions.php for a line like this:

remove_action ('woocommerce_single_product_summary hook', 'woocommerce_template_single_add_to_cart', 30);

Thanks Lorro,

Can’t seem to find that, the only lines similar to that are these (which I think do something different):

remove_action( 'woocommerce_product_tabs', 'woocommerce_product_reviews_tab', 30);
remove_action( 'woocommerce_product_tab_panels', 'woocommerce_product_reviews_panel', 30);

remove_action( 'woocommerce_after_single_product_summary', 'woocommerce_output_product_data_tabs', 10 );

remove_action( 'woocommerce_single_product_summary', 'woocommerce_template_single_title', 5 );
add_action( 'woocommerce_before_single_product_summary', 'woocommerce_template_single_title', 5 );

remove_action( 'woocommerce_after_shop_loop_item_title', 'woocommerce_template_single_title', 5 );
add_action( 'woocommerce_before_shop_loop_item_title', 'woocommerce_template_single_title', 5 );

I don’t think modifying these will help?

I have also tried putting this in to functions.php, but to no avail:

add_action ('woocommerce_single_product_summary hook', 'woocommerce_template_single_add_to_cart', 30);

Ok, so here’s the strange thing: I can get the ‘add to cart’ button to appear when I use the shortcode on a separate page: https://www.hatblocks.co.uk/test-page/ but it refuses to show within the products. Does this help anyone solve the riddle?

On the Men’s Blocks page, is that a series of shortcodes? Are the shortcodes from the list of standard shortcodes here:
https://docs.woothemes.com/document/woocommerce-shortcodes/

Please give an example shortcode.

Yes, on the men’s blocks page, it is a list of shortcodes:

[product_page id="870"]
[product_page id="1125"]
[product_page id="2177"]
[product_page id="1349"]
[product_page id="763"]
[product_page id="4551"]
[product_page id="4555"]
[product_page id="4559"]
[product_page id="4580"]
[product_page id="4584"]
[product_page id="4545"]
...etc

On the test page, it is just this:
[add_to_cart id="102"]

I think that shortcode leads to the content-single-product template. If the developer made a custom version, it will be at:
wp-content/themes/guy-morse-brown/woocommerce/content-single-product.php

If you temporarily rename the custom template, it will put it out-of-play and the default WooCommerce version will be used. If you now have the add-to-cart button, you will know it is the custom template that needs modifying.

Alas, nope. No change after renaming the file (have no reverted to original name).
Here is contents of file: https://pastebin.com/p6AjJHhc

It’s definitely something in the theme, because when I switched themes (under a theme tester plugin) the add to cart button appeared.

I also tried deleting everything from the functions.php and this didn’t help either…

The template content-single-product.php uses content-product.php to display one product, have a look in there.

I have entirely renamed the woocommerce folder within the theme (to _woocommerce) and still it won’t appear. (I’m running on a test theme at the moment, in case I break the live site.)
I’ve deleted all the styling and still no joy.

But if I switch to the parent theme, it is visible.

Ok, so here’s the very strange thing.
After going through the entire woocommerce directory, renaming everything (to deactivate it) and then restoring to its original name, the add to cart is now visible. (This is only true on the test theme that is invisible to non-admins)
I am horribly confused.
How can the process of renaming files correct the issue?

Found it!
Here’s the incriminating file:
/wp-content/themes/guy-morse-brown-2/woocommerce/single-product/add-to-cart/simple.php

This file was completely empty.
Getting rid of it cures the problem. Thanks for your help and patience ??

Hoping this may help someone else at some point.