Allow DROP TABLE schema change in uninstall.php

[Asgaros]

Plugins often require their own tables - therefore those tables naturally should be removed during the uninstall process of the plugin. This brings the requirement to execute a query like DROP TABLE IF EXISTS wp_my_table; which is placed in the uninstall.php file.

Currently, the CodeSniffer creates warnings for those database queries, like:

Attempting a database schema change is discouraged. (WordPress.DB.DirectDatabaseQuery.SchemaChange)

Since deleting unnecessary data during the uninstall process is a proper way to avoid leaving trash behind, I suggest to add an exception which allows the DROP TABLE query within the uninstall.php file.

[dingo-d]

You can just silence the direct database query sniffs in your plugin's ruleset

<rule ref="WordPress.DB.DirectDatabaseQuery.SchemaChange">
	<severity>0</severity>
</rule>

I recommend you read about modifying your ruleset, and about customizing WPCS ruleset.

[Asgaros]

Yes, I know that. Basically, I can silence every annoying warning, so at the end my code will be perfectly fine.

My point is more: This ruleset makes perfectly sense in general, so I want to keep and test code against it to ensure no schema changes are happening in the main plugin files. But at the same time, it should be a good idea to allow this kind of query during the uninstall process because it is an essential part of cleaning up and therefore should not trigger a warning there.

[dingo-d]

@jrfnl @GaryJones Could we add this exclusion to the sniff? I mean, the way I'd approach this would be to just add an exclusion for this one file in my ruleset and that'd be it.

But uninstall.php is a plugin-specific file, so it could be used as a special case.

[GaryJones]

I think checking if the file name is uninstall.php and exiting early makes sense. We already have file-specific conditions for other things (like for template files).