We use template haskell to embed the git revision into the executable. You could probably do the same for the build time. Be aware that if no sources have changed, cabal won't recompile the module so you'd end up with the old git revision/build time. Regards, Erik On Fri, Jul 11, 2014 at 11:28 AM, Vo Minh Thu wrote:

Hi Roman,

I am using this solution:

http://www.hyperedsoftware.com/blog/entries/build-info-gen.html

Cheers, Thu

2014-07-11 11:26 GMT+02:00 Roman Cheplyaka :

...

What are existing solutions for embedding version info (git revision, build date/time, versions of dependencies) in Haskell programs?

Roman

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Yes, this is a problem. To be honest, the project where I used this approach was never public, and we didn't use sdist. I think that it's possible to check if you have `git` executable, and if the the project is in repository, otherwise there is no sense in this information, and information from a cabal file that is given to the hook can be used. On 11 July 2014 16:09, Herbert Valerio Riedel wrote:

On 2014-07-11 at 11:46:36 +0200, Alexander V Vershilov wrote:

...

It's possible to use a SimpelUserHook setup type, and then in Setup.hs add preBuild hook that will generate a file in ./dist/autobuild/, then you can import this file in Main.hs and use this information.

I have used such Setup.hs (have not reviewed it for years), I think it may be improved.

Btw, the main problem with that variant is that it breaks down if you want need `cabal sdist` to work.

In order to have `cabal sdist` do something sensible I had to hack up an abomination of a `Setup.hs` which would rewrite the .cabal file and replace the `Setup.hs` by a `build-type: Simple` compliant one during `sdist` creation. It's really a pity Cabal makes this use-case so hard to achieve, as it would just need to provide a hook to determine the version-field dynamically...

Cheers, hvr

-- Alexander