Exit early if user's email address didn't change #8370

[ashleyfae]

Fixes #8370

Proposed Changes:

The only main change is this extra snippet at the very top:

$user = get_userdata( $user_id );

// Bail if the email address didn't actually change just now.
if ( empty( $user ) || $user->user_email === $old_user_data->user_email ) {
	return;
}

We exit ASAP if the user's email address didn't just change. The following code should only execute if the user's email changed to something else during the current update.

Other changes are minimal while in the area:

1. Update PhpDocs to include parameters.
2. Reformat code to exit early instead of a bunch of nested if statements.
3. Change return false; to return;
4. Add comments to action hook.
5. Remove required parameter before optional (PHP 8 error)

This fixed the memory issue for me. We should verify that this hook does still successfully run when actually changing a user's email address.

[robincornett]

I was having trouble testing this and realized that the issue was actually in FES, looks like FES_DB_Vendors->update_vendor_email_on_user_update() will need to be looked at as well.

Once I got that sorted, I was able to reproduce the issue using the code from the original issue post, and this does resolve it.