Confusing cabal solver install plan

[hvr]

Using

$ ghc --version; cabal --version
The Glorious Glasgow Haskell Compilation System, version 7.6.3
cabal-install version 1.18.0.2
using version 1.18.0 of the Cabal library 

with the dummy.cabal contents

name:                dummy
version:             0.1.0.0
license:             GPL-3
license-file:        LICENSE
author:              HVR
maintainer:          hvr@gnu.org
build-type:          Simple
cabal-version:       >=1.10

executable dummy
  main-is: dummy.hs
  build-depends:       base >=4.6 && <4.8
  default-language:    Haskell2010

test-suite test1
  main-is: dummy.hs
  type: exitcode-stdio-1.0
  default-language: Haskell2010
  build-depends: test-framework==0.8.*, test-framework-quickcheck2==0.3.*, QuickCheck==2.5.*

Then if I install some packages into the sandbox...

$ cabal sandbox init
$ cabal install QuickCheck-2.6
$ cabal install --enable-test --dep --dry
Resolving dependencies...
In order, the following would be installed (use -v for more details):
QuickCheck-2.5.1.1 (latest: 2.6)
ansi-terminal-0.6
ansi-wl-pprint-0.6.6
extensible-exceptions-0.1.1.4
hostname-1.0
text-0.11.3.1
transformers-0.3.0.0
mtl-2.1.2
regex-base-0.93.2
regex-posix-0.95.2
xml-1.3.13
test-framework-0.8
test-framework-quickcheck2-0.3.0.1
$ cabal install --enable-test --dep

...and now try to cabal install, cabal would try to install test-framework-quickcheck2-0.2.4 even though tests are not to be built, and even if they were to be built, that version would not be within the version constraints:

$ cabal install --disable-test --dry 
Resolving dependencies...
In order, the following would be installed (use -v for more details):
dummy-0.1.0.0
test-framework-quickcheck2-0.2.4 (latest: 0.3.0.1)

[hvr]

Here's the -v3 output from the last command for completeness:

$ cabal install --disable-test -v2 --dry 
Using a sandbox located at /home/hvr/Haskell/bugs/cabal-solver/.cabal-sandbox
Reading available packages...
Reading available packages...
Reading installed packages...
'/opt/ghc/7.6.3/bin/ghc-pkg' 'dump' '--package-db=/home/hvr/Haskell/bugs/cabal-solver/.cabal-sandbox/x86_64-linux-ghc-7.6.3-packages.conf.d' '-v0'
'/opt/ghc/7.6.3/bin/ghc' '--print-libdir'
Reading available packages...
Choosing modular solver.
Resolving dependencies...
In order, the following would be installed:
dummy-0.1.0.0 (new package)
test-framework-quickcheck2-0.2.4 (latest: 0.3.0.1) (new version)
hvr@duo:~/Haskell/bugs/cabal-solver$ cabal install --disable-test --dry 
Resolving dependencies...
In order, the following would be installed (use -v for more details):
dummy-0.1.0.0
test-framework-quickcheck2-0.2.4 (latest: 0.3.0.1)
hvr@duo:~/Haskell/bugs/cabal-solver$ cabal install --disable-test -v3 --dry 
Using a sandbox located at /home/hvr/Haskell/bugs/cabal-solver/.cabal-sandbox
Searching for ghc in path.
Found ghc at /opt/ghc/7.6.3/bin/ghc
("/opt/ghc/7.6.3/bin/ghc",["--numeric-version"])
/opt/ghc/7.6.3/bin/ghc is version 7.6.3
looking for tool ghc-pkg near compiler in /opt/ghc/7.6.3/bin
found ghc-pkg in /opt/ghc/7.6.3/bin/ghc-pkg
("/opt/ghc/7.6.3/bin/ghc-pkg",["--version"])
/opt/ghc/7.6.3/bin/ghc-pkg is version 7.6.3
("/opt/ghc/7.6.3/bin/ghc",["--supported-languages"])
("/opt/ghc/7.6.3/bin/ghc",["--info"])
The package database already exists:
/home/hvr/Haskell/bugs/cabal-solver/.cabal-sandbox/x86_64-linux-ghc-7.6.3-packages.conf.d
Reading available packages...
Reading available packages...
Reading installed packages...
("/opt/ghc/7.6.3/bin/ghc-pkg",["dump","--package-db=/home/hvr/Haskell/bugs/cabal-solver/.cabal-sandbox/x86_64-linux-ghc-7.6.3-packages.conf.d","-v0"])
("/opt/ghc/7.6.3/bin/ghc",["--print-libdir"])
Reading installed packages...
("/opt/ghc/7.6.3/bin/ghc-pkg",["dump","--global","-v0"])
("/opt/ghc/7.6.3/bin/ghc-pkg",["dump","--package-db=/home/hvr/Haskell/bugs/cabal-solver/.cabal-sandbox/x86_64-linux-ghc-7.6.3-packages.conf.d","-v0"])
("/opt/ghc/7.6.3/bin/ghc",["--print-libdir"])
Reading available packages...
Choosing modular solver.
Resolving dependencies...
[__0] trying: QuickCheck-2.6/installed-e3d... (user goal)
[__1] trying: base-4.6.0.1/installed-8aa... (dependency of QuickCheck-2.6/installed-e3d...)
[__2] trying: rts-1.0/installedbuil... (dependency of base-4.6.0.1/installed-8aa...)
[__3] trying: integer-gmp-0.5.0.0/installed-2f1... (dependency of base-4.6.0.1/installed-8aa...)
[__4] trying: ghc-prim-0.3.0.0/installed-d52... (dependency of base-4.6.0.1/installed-8aa...)
[__5] trying: template-haskell-2.8.0.0/installed-a30... (dependency of QuickCheck-2.6/installed-e3d...)
[__6] trying: pretty-1.1.1.0/installed-661... (dependency of template-haskell-2.8.0.0/installed-a30...)
[__7] trying: containers-0.5.0.0/installed-ab1... (dependency of template-haskell-2.8.0.0/installed-a30...)
[__8] trying: deepseq-1.3.0.1/installed-5cc... (dependency of containers-0.5.0.0/installed-ab1...)
[__9] trying: array-0.4.0.1/installed-3b7... (dependency of containers-0.5.0.0/installed-ab1...)
[_10] trying: QuickCheck-2.6/installed-e3d... (user goal)
[_11] trying: ansi-terminal-0.6/installed-0cc... (user goal)
[_12] trying: unix-2.6.0.1/installed-f12... (dependency of ansi-terminal-0.6/installed-0cc...)
[_13] trying: time-1.4.0.1/installed-10d... (dependency of unix-2.6.0.1/installed-f12...)
[_14] trying: old-locale-1.0.0.5/installed-672... (dependency of time-1.4.0.1/installed-10d...)
[_15] trying: bytestring-0.10.0.2/installed-4f9... (dependency of unix-2.6.0.1/installed-f12...)
[_16] trying: ansi-wl-pprint-0.6.6/installed-fb6... (user goal)
[_17] trying: extensible-exceptions-0.1.1.4/installed-255... (user goal)
[_18] trying: hostname-1.0/installed-7cd... (user goal)
[_19] trying: mtl-2.1.2/installed-94c... (user goal)
[_20] trying: random-1.0.1.1/installed-43f... (user goal)
[_21] trying: regex-base-0.93.2/installed-f94... (user goal)
[_22] trying: regex-posix-0.95.2/installed-a7e... (user goal)
[_23] trying: test-framework-0.8/installed-e81... (user goal)
[_24] next goal: test-framework-quickcheck2 (user goal)
[_24] rejecting: test-framework-quickcheck2-0.3.0.1/installed-1d0... (conflict: QuickCheck==2.6/installed-e3d..., test-framework-quickcheck2 => QuickCheck==2.5.1.1/installed-4f8...)
[_24] rejecting: test-framework-quickcheck2-0.3.0.1, 0.3.0, 0.2.12.4, 0.2.12.3 (conflict: QuickCheck==2.6/installed-e3d..., test-framework-quickcheck2 => QuickCheck>=2.4 && <2.6)
[_24] rejecting: test-framework-quickcheck2-0.2.12.2, 0.2.12.1 (conflict: QuickCheck==2.6/installed-e3d..., test-framework-quickcheck2 => QuickCheck>=2.4 && <2.5)
[_24] rejecting: test-framework-quickcheck2-0.2.12, 0.2.11, 0.2.10 (conflict: test-framework==0.8/installed-e81..., test-framework-quickcheck2 => test-framework>=0.2.0 && <0.5.0)
[_24] rejecting: test-framework-quickcheck2-0.2.9, 0.2.8, 0.2.7, 0.2.6 (conflict: test-framework==0.8/installed-e81..., test-framework-quickcheck2 => test-framework>=0.2.0 && <0.4.0)
[_24] rejecting: test-framework-quickcheck2-0.2.5 (conflict: test-framework==0.8/installed-e81..., test-framework-quickcheck2 => test-framework>=0.2.0 && <0.3.0)
[_24] trying: test-framework-quickcheck2-0.2.4
[_25] trying: test-framework-quickcheck2-0.2.4:+base4
[_26] trying: test-framework-quickcheck2-0.2.4:-base3
[_27] trying: text-0.11.3.1/installed-e38... (user goal)
[_28] trying: transformers-0.3.0.0/installed-ff2... (user goal)
[_29] trying: xml-1.3.13/installed-883... (user goal)
[_30] trying: dummy-0.1.0.0 (user goal)
[_31] trying: dummy-0.1.0.0:!test
[_32] done
In order, the following would be installed:
dummy-0.1.0.0 (new package)
test-framework-quickcheck2-0.2.4 (latest: 0.3.0.1) (new version)

[tibbe]

@kosmikus would you mind doing an initial triage, just to describe what's going on?

[kosmikus]

I think that @23Skidoo knows the sandbox stuff better than I do. Here's what seems to happen according to the -v3 log:

QuickCheck-2.6 seems to be installed in the sandbox (possibly next to QuickCheck-2.5? I thought that's not possible?). Within a sandbox, there's an attempt to create a consistent install plan with all installed packages, so both QuickCheck and test-framework-quickcheck2 which are currently installed become user goals. But they turn out to be inconsistent.

Right now, it's unclear to me if this is a problem that should be solved within the solver somehow, or whether the solver could be invoked with better arguments to make it clear what's desired.

[gbaz]

closing as obsolete