Oddity with 'cabal install' in GHC 7.4.1

Andres Löh andres.loeh at googlemail.com
Sun Feb 5 09:43:06 CET 2012

Hi Conal.

> Thanks for the reply! Note that I get this message even running 'cabal
> install' a second time after changing nothing. Is that scenario an example
> of what you mean by a "potentially dangerous cabal invocation"?

The check currently is entirely ad-hoc. Any reinstallation of an
existing package triggers the warning. There's no hash comparison.

> I've been
> unable to avoid this error message by any other means that (a) 'ghc-pkg
> unregister <package>' or (b) '--force-reinstall'. So far, '--solver=modular'
> hasn't helped. So I'm hoping for something less aggressive. In particular,
> in case nothing has changed, I want 'cabal install' to succeed (exit code 0)
> so that my automated build & install & release processes will continue
> rather than get stopped.

The message appears, but building should work, with --force-reinstall
and no --dry-run. Can you confirm that you've tried that?


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