RFE: Make template-haskell cabal package require a specific version of GHC
Following a conversation on another bug tracker: https://github.com/bos/math-functions/issues/52
it looks like template-haskell is very dependent on the version of GHC being used (although the test matrix is all green at present). In the above case we're trying to use template-haskell 2.12.0.0 with GHC 8.0.2 to build another package and that fails.
One of the problems is that on Fedora template-haskell is shipped separately from GHC while on Debian or with source installations it comes bundled with GHC.
Is it possible to specify a requirement on the GHC version inside .cabal files? This will make it easier to track down why something isn't able to compile.
Trac metadata
| Trac field | Value |
|---|---|
| Version | 8.0.2 |
| Type | FeatureRequest |
| TypeOfFailure | OtherFailure |
| Priority | normal |
| Resolution | Unresolved |
| Component | Template Haskell |
| Test case | |
| Differential revisions | |
| BlockedBy | |
| Related | |
| Blocking | |
| CC | |
| Operating system | |
| Architecture |
Activity
added Tfeature request TemplateHaskell Trac import labels
Indeed, upgrading
template-haskellis almost always a bad idea. That's whycabal-install's solver considers `template-haskell` to be a non-upgradeable package.Here's some more backstory:
Long story short, if use a recent enough
cabal-installthis shouldn't be a problem.More generally, one long-standing idea was to have either
ghcorghc-pkgexpose the information of whether a package is reinstallable dynamically to cabal, but in the past that would have been merely an aesthetical improvement, as Cabal has to encode special knowledge about GHC anyway. Also, the small set of non-reinstallable packages has been very stable over the years; so there was little incentive to do anything about this.added Pnormal label
