largo_category_and_tags does not accept specification of an arbitrary post ID

[benlk]

Consider the following code:

largo_top_term( array('post' => 5 ) );

Assuming that post 5 has a top term set, the top term returned will be that set on post 5.

If no top term is set on post 5, largo_top_term() calls largo_category_and_tags() to get a list of categories and tags. That function doesn't use post 5, but instead fetches terms from the get_the_ID() post, which in many situations (like the homepage) is not the post that we want terms for.

There are two situations to consider:

1. On a largo_top_term() call with a specificied post that does not match the global post ID. In this situation, we should not call largo_category_and_tags(), because its output will be wrong.
2. On a largo_top_term() call with no post specified, largo_top_term() will get the post ID to use from get_the_ID() the same as largo_category_and_tags(). This use case includes the top term on single posts.

Identified during work on #1646

[benlk]

We can't remove largo_category_and_tags() from largo_top_term() as a fallback, yet, but we should not also go around outputting incorrect terms. Until largo_category_and_tags() is refactored to make it easier to specify the post ID, we can check in largo_top_term() for a mismatch between the specified post ID and the global post ID, and not call largo_category_and_tags() in that situation.

[benlk]

Post-#1648, our next steps are:

• refactor or remove largo_category_and_tags().

Remove: https://github.com/INN/largo/blob/512da701664b329f2f92244bbe54880a6e146431/inc/related-content.php#L399-L431

Refactor: https://github.com/INN/largo/blob/512da701664b329f2f92244bbe54880a6e146431/inc/related-content.php#L235-L250