Spurious warning: The package has an extraneous version range for a dependency on an internal library

[phadej]

% cabal new-build cabal-plan:exe:cabal-plan
Resolving dependencies...
Build profile: -w ghc-8.2.2 -O1
In order, the following will be built (use -v for more details):
 - cabal-plan-0.3.0.0 (lib) (first run)
 - cabal-plan-0.3.0.0 (lib:topograph) (first run)
 - cabal-plan-0.3.0.0 (exe:cabal-plan) (first run)
Configuring library for cabal-plan-0.3.0.0..
Configuring library 'topograph' for cabal-plan-0.3.0.0..
Preprocessing library for cabal-plan-0.3.0.0..
Building library for cabal-plan-0.3.0.0..
Preprocessing library 'topograph' for cabal-plan-0.3.0.0..
Building library 'topograph' for cabal-plan-0.3.0.0..
[1 of 1] Compiling Cabal.Plan       ( src/Cabal/Plan.hs, /home/ogre/Documents/shared-haskell/cabal-plan/dist-newstyle/build/x86_64-linux/ghc-8.2.2/cabal-plan-0.3.0.0/build/Cabal/Plan.o )
[1 of 1] Compiling Topograph        ( src-topograph/Topograph.hs, /home/ogre/Documents/shared-haskell/cabal-plan/dist-newstyle/build/x86_64-linux/ghc-8.2.2/cabal-plan-0.3.0.0/l/topograph/build/topograph/Topograph.o )
Configuring executable 'cabal-plan' for cabal-plan-0.3.0.0..
Warning: The package has an extraneous version range for a dependency on an
internal library: cabal-plan -any && ==0.3.0.0 && ==0.3.0.0. This version
range includes the current package but isn't needed as the current package's
library will always be used.

There aren't such additional version restriction:

executable cabal-plan
  default-language:    Haskell2010
  other-extensions:    RecordWildCards

  main-is: src-exe/cabal-plan.hs
  other-modules: Paths_cabal_plan

  if flag(exe)
    -- dependencies w/ inherited version ranges via 'cabal-plan' library
    build-depends: cabal-plan
                 , topograph
....

To help bisecting:

ii  cabal-install-head                              2.1+git20180202.0.2773999-5~16.04             amd64        Command-line interface for Cabal and Hackage

previous cabal-install-head (from around 2017-01-15) didn't had this issue, IIRC.

[Ericson2314]

Yeah this me. My refactor PRs should fix this, but if there are too much for 2.1 should we do something else? You can bisect the test suit to see when.

[Ericson2314]

#4383 caused this.

[phadej]

@Ericson2314 is it easy (or possible) to fix without big (including data-type) changes?

[Ericson2314]

Actually, there might be. The type changes more help make sure its done correctly than fix the problem in itself. Basically, i need to make sure that checking always comes after whatever elaborates the package-local build tool depends.

[Ericson2314]

And we'd technically need to like phantom type GenericPackageDescription assert its been checked, too, for a real type-directed solution.

[Ericson2314]

@phadej I think what would be easiest is to do the 2.1 branch, land the refactors, find the fix, and then backport it.

[phadej]

@Ericson2314 than I'd opt to revert #4383 in 2.2 branch, this warning is so annoying (and plain wrong), we cannot have release with this either.

EDIT because there's hardly time to review refactoring, at least I don't have. I'm very very sorry.

[phadej]

Also note that #4383 landed only 8 days ago. IMO too late for release.

[Ericson2314]

@phadej No worries, I'm fine with reverting on 2.2. I meant backporting the fix without refactors, to be clear, but agreed that last PR is not that much less invasive than the others.

[Ericson2314]

As of #5148 this is just a problem on master.

[quasicomputational]

This is going to be a problem for 2.4.