Cabal irretrievably broken; what can I try next?

3
votes

I can neither install or update packages using cabal, in fact, I get the message that Cabal is 'unusable'. I am stuck at Cabal-1.10.

So, I had the idea to manually install some packages.

First I tried 'directory': but no, that requires Distribution.Simple which is reported as 'missing'.

That issue can be resolved by installing a new version of Cabal manually: 1.16.0.1.

But no, that fails because it can't find 'directory'.

Therefore to install 'directory' I must have Cabal; to install Cabal I must have 'directory'.

This is recursion, but not the way we want it!

Are there any options to resolve this cyclic dependency other than a complete uninstall and reinstall of the Haskell Platform?

(I'm running Windows 7, by the way)

1
haskellcabal
This is a real question, neither ambiguous, vague, incomplete, overly broad nor rhetorical, and can be answered in the form it was - there's already a relevant and helpful answer. It was clear to anyone who understands cabal what is being asked here. I've slightly reworded it but am 125 short of enough rep to cast a reopen vote myself. - AndrewC
Please don't paraphrase error messages, paste the actual, exact error messages (perhaps not the complete messages if they're long, but then the first lines). The error messages usually contain important details that makes it easier to figure out what exactly the problem is. In your case, additionally the output of ghc-pkg check would be very helpful to find out whether you have lost some packages or installed multiple versions and thus broken some, and consequently how to fix it. - Daniel Fischer

1 Answers

5
votes

If you have been installing everything locally (the recommended way), just nuke the GHC directory. I don't know where this is on Windows, but in *nix it's ~/.ghc, if that gives a hint. If you've been installing packages globally, then yes, reinstall the Platform (or just GHC).

In the future, you will have a much better time if you don't let cabal (re)install any of the packages in this list. You might consider upgrading cabal-install, as newer versions are much more conservative about reinstalls.