(Imported from Trac #613, reported by guest on 2009-11-28)
When cabal-install is upgraded, it sometimes gains new features with corresponding lines in the default .cabal/config; however, the existing .cabal/config is not updated.
One way of updating it would be to make it, at every invocation of cabal-install, rewrite the file using a merger of the current configuration and the default one.
There are some issues with this - most particularily, user-written comments in the file should be preserved, without this stopping cabal-install from inserting its own comments for (disabled) new features, or causing duplication of comments.
None of this is particularily hard to imagine a solution for, but in the interests of avoiding priming, I won't write down my own suggested solutions here. If whoever eventually decides to try fixing this explains his proposed solution here, I'll chime in then.
Given that this ticket hasn't had any activity since 2009, I propose closing. Please open a new issue, or re-open if this is still desired.