This commit reverts the functionality introduced in PR #26260
(later refined by #27175, #27190, #27508) in which filtering by
attribute using the layered nav widget was improved to handle the
cases of variations out of stock. The revert is a response to the
numerous problems reported by users in Woo 4.4 and 4.5
Not all the code has been reverted, only the code that resulted in
visible functionality changes. Thus, the code that generates
term relationships for variations is still in place to keep database
consistency and to keep the reverting changes to the minimum needed.
The new query fixes a bug where variations were being counted twice:
if a product was included in both the queries then it would be counted
differently and added; e.g. when a product had two variations,
one with "Any" attribute and other with a attribute that has a value.
The new query also optimizes performance, so that filter conditions
can be improved and better indexes can be used.
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 new variation attribute is added, the corresponding 'attribute_'
meta entries are added for all variations with an empty value;
and when an existing variation attribute is removed, the existing
'attribute_' meta entries are deleted for all variations.
This is necessary for the filter by attribute widget to work properly
when variations exist with a value of "Any..." for attributes.
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.
Claudio Sanches
Christopher Allford
Ron Rennick
jonathansadowski
Nestor Soriano
vedanshujain
Julia Amosova
Tam Mullen