OK, so there are more than one question in here, so let me address some of them… Why you should never modify WordPress core files? In short words… Because it will be really hard to manage later on… If you modify the core, than you won’t be able to update it – so what, when … Read more
Yes, it is possible. You can modify that file and use it. But… It will be a lot of work to maintain those changes. You’ll have to merge them after every WordPress update and check if these changes don’t break anything in WP. That’s why such modifications aren’t very common practice and they’re not recommended.
Read the thread Disable/ Stop “auto-draft” posts on wp-hackers to understand why this is a very bad idea. Let me quote the explanations from @Otto: Auto-drafts exist because of the fact that multiple users can create new posts at the same time. If two people enter post-new at roughly the same moment, then have their … Read more
In general, no. Once you delete a post or a file you can’t “bring them back” just by reversing the admin actions, for that you will need to store the various states of the system and not only the hooks that have been used.
I threw this question around on Twitter and asked for feedback from some other core developers. My gut instinct was to make $current_url either filterable or generated by a function that could be overridden. This is, apparently, the wrong way about it. @markoheijnen: @EricMann Resetting $_SERVER[‘HTTP_HOST’] sounds like a hackish solution. Same code then can … Read more