The new query doesn't need empty attribute entries in the meta table,
therefore the code that generates them and the migration to backfill
the missing existing ones have been removed.
Right now the filter by attributes widget counts available variations
(for variation products). This is confusing since the counter shows
numbers that are higher than the actual count of products displayed.
This commit changes the query used by the widget so that instead
of counting variations it returns the parent product ids, and then
counts the distinct values. This also covers the case of products
where some of the variations have concrete values and some have
"Any..." values.
When a variation product has an attribute with a value of "Any...",
and there's a filter by attribute widget for that attribute, then
that product won't be included in the counts displayed in the widget
(and if the count ends up being zero, the attribute won't be shown
in the widget).
This happens before since Woo 4.4, this widget works by looking at
entries in the term relationships table for varitions too
(used to do so for simple products and for "main" variable products
only), see PR #26260; but there are no such entries for
"Any..." attributes.
This commit fixes that by extending the SQL query used by the widget
to look for variations that have empty attribute values in the meta
table too.
After the change that registers variation attributes as terms
(in addition to reigstering them as post meta) it is now time
to modify the get_filtered_term_product_counts methods in
WC_Widget_Layered_Nav so that it works consistently for both
variable and non-variable products. The logic for the counters
is now as follows:
with OR operator:
- Simple products: count the attributes of all visible products
(unchanged behavior).
- Variable products: count attributes corresponding to
visible variations.
with AND operator:
- Simple products: count the attributes of visible products but only
for products that have all the selected (unchanged behavior).
- Variable products: find all the products for which all the variations
corresponding to the selected attributes exist and are visible,
then count the attributes corresponding to the visible variations
of those products.
A product is "visible" if it's published, not excluded for catalog,
and has stock. Additionally, a variable product will not be considered
visible if the parent product is not.