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

Great! Thanks. I adapted that trick and it worked fine: https://github.com/rrnewton/haskell-lockfree-queue/blob/cb8ca1a5d8b4c02e45ee... On Wed, May 22, 2013 at 11:53 PM, Carter Schonwald < carter.schonwald@gmail.com> wrote:

Hey Ryan, I ran into a related issue, heres a a way you can do this safe IN the cabal file (or at least you can modify my hack for your purposes)

heres a link to the workaround I did for making LLVM-hs work across >= 1.17 and < 1.17 cabal, but you could abuse it to make sure setup.hs barfs on old cabal https://github.com/bos/llvm/blob/master/base/Setup.hs#L89-L116

heres a quick one off gist that takes my trick and does something helpful for you variant + makes sure the tool can't build otherwise

https://gist.github.com/cartazio/5632636

I just wrote a snippet that you can just add to your setup.hs and it should guarantee the setup.hs will barf with a helpful error message on cabal < 1.17.0

On Wed, May 22, 2013 at 10:50 PM, Ryan Newton wrote:

...

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 packagehttp://hackage.haskell.org/package/atomic-primops-0.1.0.2to 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" $* }

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