Build failure from mtl-compat overhaul

[snoyberg]

Preprocessing library haxr-3000.10.4.1...

Network/XmlRpc/Server.hs:35:18:
    Could not find module ‘Control.Monad.Except’
    It is a member of the hidden package ‘mtl-compat-0.2.1.3’.
    Perhaps you need to add ‘mtl-compat’ to the build-depends in your .cabal file.
    Use -v to see a list of the files searched for.

[peti]

Same here: http://hydra.cryp.to/build/579020/log/raw.

[byorgey]

Hmm, thanks for the report. My travis build is succeeding (https://travis-ci.org/byorgey/haxr/builds/51775356); what would be the difference?

In any case, what is the current best practice with regard to mtl/transformers stuff? I have been somewhat out of the loop.

[snoyberg]

My guess is that you're building with transformers 0.4. The best practice here is likely to just add transformers-compat and/or mtl-compat to your build-depends, which should solve this problem.

[byorgey]

OK, I just uploaded haxr-3000-10-4-2 which adds an mtl-compat dependency. As far as I understand this should fix the problem; but since my travis build was succeeding previously, I can't really tell. Please let me know whether I can close this ticket. Thanks!

[snoyberg]

@byorgey I'll close the issue for now, and if there are problems with future Stackage builds, I'll reopen. Thanks for the quick response!