[Haskell-cafe] How to throw an error if using "cabal-install" < version XYZ?

Ryan Newton rrnewton at gmail.com
Thu May 23 04:50:08 CEST 2013


A cabal-install bug <https://github.com/haskell/cabal/issues/1284> was
fixed recently that pertains to building C libraries with profiling.

As a result, I want a certain
package<http://hackage.haskell.org/package/atomic-primops-0.1.0.2>to
test if cabal-install < 0.17.0 is used, and throw a preemptive error.
 Otherwise this package fails in weird ways at runtime (it's a nasty one).

I noticed with some surprise the following sequence:

*   $ cabal --version*
*   cabal-install version 1.16.0.2*
*   using version 1.16.0.3 of the Cabal library*
*   $ cabal clean*
*   $ cabal install*
*   $ cat dist/build/autogen/cabal_macros.h  | grep VERSION_Cabal*
*   #define VERSION_Cabal "1.17.0"*

Alright, so that, in retrospect, makes sense.  The version is which *my*
library is linked with is the relevant one, not the one cabal-install was
linked with [1].

So the natural next thought is to move the MIN_VERSION_Cabal test into
Setup.hs, and force cabal to use it by setting the build type to Custom.
 But... I just learned from this ticket that the cabal macros are not
available in Setup.hs:

   http://hackage.haskell.org/trac/hackage/ticket/326

Uh oh, what's left?

 -Ryan

[1] P.S. Personally I'm now using a bash function like below, to force the
two versions to be the same:

function safe_cabal_install () {
  VER=`cabal --version | tail -n1 | awk '{ print $3 }'`
  cabal install --constraint="Cabal==$VER" $*
}
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/haskell-cafe/attachments/20130522/2b285928/attachment.htm>


More information about the Haskell-Cafe mailing list