Upper bound on "time" in Cabal causes build failure
toby at paccrat.org
Wed Dec 17 09:52:07 UTC 2014
Hi cabal developers,
Wasn't sure what best to do with this - please let me know if you'd rather I emailed it elsewhere, or opened an issue against the github project, or...
I'm trying to build haskell-platform-2014.2 from source, with the latest cabal:
cabal-install version 184.108.40.206
using version 220.127.116.11 of the Cabal library
The build plan it constructs for the hptool sandbox includes Cabal-1.2.4! (That's not a typo.) The problem seems to be that it chooses time-1.5, and then discovers that all recent versions of Cabal have the constraint "time < 1.5", so digs up this fossil from the attic.
So I think there are two problems here. The small and simple one is that we need a release of Cabal with "time < 1.6" - you appear to have this in the master branch already; can it go on the 1.20 branch? Do you want me to create an issue / pull request?
The larger problem is that cabal should have found a better build plan. I'm naive about the internals of dependency resolution, but I would have expected it to prefer taking time back 1 release over taking Cabal back 18. It would also be nice if it could have deduced that Cabal-1.2.4 wasn't actually going to build with recent ghc versions.
Thanks for your time,
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