It does not make a backup.
That said, if your theme was gone, I’m going to take a wild guess and say you updated the default theme directly. As painful as this is, that’s not a bug, that’s a feature. And yes, it’s not notified, and yes, I think it should be, but it’s never been and after this long, most of us learn :/ Sometimes the hard way. Sorry.
When WP upgrades, the plugins Akismet and Hello Dolly get updated, as well as the themes Default and Classic. ALWAYS.
If you want to use one of those themes as your ‘base’, I would suggest either copying it and renaming it (My-Default) or making a child theme of it for next time.
I just had the same problem and lost a bunch of customization and am not feeling too happy. Could you please reconsider notifying people of this so that they don’t all have to learn the hard way? This is my first time using this kind of website management and I chose WordPress because it is otherwise fairly easy.
kiravae said:
Could you please reconsider notifying people of this so that they don’t all have to learn the hard way?
At the top of the Tools->Upgrade screen it says in a message box:
Important: before upgrading, please backup your database and files.
Interestingly, there were some thoughts in trac to remove that message but I can’t find that right now.
It’s one of those things where I can argue both sides of the problem (and so can everyone I bet).
There should be some way to tell people ‘Hey, you’ve updated default. This will be updated when your blog is upgraded. Make a copy or a child theme!’ but I’ve never managed to think up some useful way of implementing it. WP can’t check for it, since file-edit-time won’t work, and verifying each and every file before an upgrade would kill some servers :/
