Re: Oddity with 'cabal install' in GHC 7.4.1

Hi Andres, 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"? 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. Regards, - Conal On Sat, Feb 4, 2012 at 9:51 PM, Andres Löh wrote:

Hi Conal.

On Sun, Feb 5, 2012 at 12:36 AM, Conal Elliott wrote:

...

Since upgrading to 7.4.1, if I 'cabal install' successfully and then 'cabal install' a second time without first doing a 'ghc-pkg unregister <package-name>', I get the following complaint:

[...]

The warning is intended to prevent you from breaking your system without knowing that you know that you're running a potentially dangerous cabal invocation.

The --force-reinstalls flag should always make it build. If it doesn't, it's a bug.

In addition, I'm planning to make the warning a little bit less aggressive before the release.

...

The only path I've found so far that's willing to rebuild or even say nothing needs rebuilding (when nothing does) is to 'ghc-pkg unregister' and then 'cabal install' again. I'm getting the same behavior on Red Hat 5 and Mac OS 10.6.8, both compiled from sources.

I'd be surprised if the OS matters. But as I said, I've not yet encountered a situation where it wouldn't build given --force-reinstalls.

Cheers, Andres