Re: Rollback problems

[Andreas Enge]

Am Mittwoch, 23. Januar 2013 schrieb Ludovic Courtès:

> And what if you roll back once you’re at the empty profile?

 

Then nothing should happen.

 

> It seems more intuitive for me to error out like this, because there was

> really nothing but nothingness before “hello” was installed. :-)

> WDYT?

 

No, I disagree; when I have nothing, install hello and roll back, I should be back to nothing. Some other opinions would be useful on this matter.

 

> This is expected (same behavior as nix-env.) Profile generations are

> not deleted unless you explicitly do so; this is what guarantees that

> one can roll back anywhere they want.

>

> But I wonder if this is really worth the trouble. In my experience, a

> scenario like the one above rarely happens, if ever.

 

I find the behaviour of roll back currently very confusing, and the situation looks reasonable to me:

I install hello, it works, so I keep it.

I install freetype, it does not work, so I drop it again.

I install file, it does not work, so I drop it again.

Now I expect to have only hello, but I have hello and freetype.

 

Of course, instead of rolling back, I can also uninstall. But the same situation occurs when one replaces the package names by different versions, I suppose.

 

I see installing packages and rolling back as steps forward and backward. Going into direction B and back, then going into direction C and back should not leave me with one step forward in direction B.

 

Note that I did not use nix before; so I am just arguing from what would intuitively be the correct behaviour of --roll-back for me: Being in situation A, doing something to bring me into situation B and rolling back should put me into situation A again, not something that resembles situation A, but with memories of B.

 

Again, some other opinions would be useful.

 

Andreas