get_submit_button uses incorrect check for delete class

[rmccue]

get_submit_button has a special case for the delete type:

if ( 'delete' === $type )
	$class = 'button-secondary delete';

However, type can never actually be 'delete', as it's always an array:

if ( ! is_array( $type ) )
	$type = explode( ' ', $type );

I'm not sure this is actually useful to fix though, since .delete doesn't seem to have any styling.

[morganestes]

Came across this today and wanted to chime in. I also didn't find any styles for .delete that would apply to this input, but since the 'delete' === $type is always false, the classes applied to the element are button delete instead of button-secondary delete, and that could end up affecting the UI.

However in the case I ran into today, both .button and .button-secondary get the exact same styles applied unless true is passed to get_submit_button() to wrap the input in a p, but the only difference there is a slight adjustment to vertical-align.

In searching for places that use 'delete' in core, I found only one use: in widgets.php ("Clear Inactive Widgets"). I'm assuming this hasn't cropped up sooner since that form relies on the removeinactivewidgets value to trigger its purpose and ignores the classes set.

[afercia]

Seems the relevant changeset is [21789]: there was a switch before the change and as far as I see the delete case was there just to ensure the delete class was always paired with button-secondary. Maybe those two lines could be removed now since button-secondary should not be used (it's not responsive and doesn't reset the outline property on focus) and the default behaviour is to always have the base button class so the result is button delete.

[sstoqnov]

The two lines have been removed, since the type is always an array and this check is useless.

[afercia]

In 39059:

Administration: remove a leftover check from get_submit_button.

Props sstoqnov.
Fixes #34891.