This commit changes the value of the option 'woocommerce_queue_flush_rewrite_rules' to 'no' instead of deleting it when rewrite rules are flushed. This way this option is autoloaded and the `get_option()` call below doesn't trigger a select query to the database on every request.
61f037060b/includes/class-wc-post-types.php (L514)
WC seems to use 'yes' and 'no' instead of 'true' and 'false' as the values of boolean options, so this commit changes the value of the option woocommerce_queue_flush_rewrite_rules to follow this pattern. Also, the string 'false' can induce bugs as it is truthy.
Since WC 3.3.1, the following query is executed on every page load:
```
UPDATE `wp_options` SET `option_value` = '1' WHERE `option_name` = 'current_theme_supports_woocommerce'
```
This is happening because of the following call to `update_option()`:
```
update_option( 'current_theme_supports_woocommerce', current_theme_supports( 'woocommerce' ) ? 1 : 0 )
```
(02cac7d637/includes/class-wc-post-types.php (L268))
`update_option()` shouldn't update the option when the value hasn't changed, but in this case it is updating on every request because, when the current theme supports WC, `1` (integer) is passed to `update_option()` and this function internally compares it against the old value stored in the database which is `"1"` (string). A strict comparison (`===`) is used (f3eaddd2dc/wp-includes/option.php (L343)), so the function assumes that the value changed and proceeds with the update.
This PR fixes this problem by using the values `"yes"` and `"no"` instead of `1` and `0`.
There were two outdated lists of WC tables. One used to drop tables when WC is uninstalled and another one to drop tables when a site is deleted in a multi site environment. This commit creates a new unified list of WC tables, adds the missing tables to this list and introduces a unit test that will fail if the list gets outdated.
WC doesn't support downgrades but the if condition that decides whether or not to call WC_Install::install() and apply database schema changes was checking if the WC version stored in the database is equal to the WC version in the code. This commit changes the check performed inside the if condition to verify if the WC version stored in the database is smaller than the version in the code. This way `dbDelta()` won't be called automatically by WC and revert database schema changes. This is particulary important for clustered providers where the version of the WC code running in one of the containers could be outdated and trigger a database downgrade.
Mike Jolley
Gerhard Potgieter
Rodrigo Primo
Caleb Burks
Claudiu Lodromanean
Claudio Sanches
Anh Hoang Nguyen
nishitlangaliya
Shiva Poudel