Related
When I try to add scotty package to my multi-project cabal file, I get following dependency conflict. I am not exactly sure what it means.
harshal#Harshals-Linux hello-haskell % cabal build
Resolving dependencies...
Error: cabal: Could not resolve dependencies:
[__0] trying: playground-0.1.0.0 (user goal)
[__1] trying: scotty-0.12.1 (dependency of playground)
[__2] trying: warp-3.3.23 (dependency of scotty)
[__3] trying: unix-compat-0.6 (dependency of warp)
[__4] trying: unix-2.7.3/installed-2.7.3 (dependency of warp)
[__5] next goal: directory (dependency of playground)
[__5] rejecting: directory-1.3.7.1/installed-1.3.7.1 (conflict: playground =>
directory>=1.3.8.0)
[__5] rejecting: directory-1.3.8.0 (conflict: unix==2.7.3/installed-2.7.3,
directory => unix>=2.8.0 && <2.9)
[__5] rejecting: directory-1.3.7.1 (conflict: playground =>
directory>=1.3.8.0)
[__5] skipping: directory-1.3.7.0, directory-1.3.6.2, directory-1.3.6.1,
directory-1.3.6.0, directory-1.3.5.0, directory-1.3.4.0, directory-1.3.3.2,
directory-1.3.3.1, directory-1.3.3.0, directory-1.3.2.2, directory-1.3.2.1,
directory-1.3.2.0, directory-1.3.1.5, directory-1.3.1.4, directory-1.3.1.3,
directory-1.3.1.2, directory-1.3.1.1, directory-1.3.1.0, directory-1.3.0.2,
directory-1.3.0.1, directory-1.3.0.0, directory-1.2.7.1, directory-1.2.7.0,
directory-1.2.6.3, directory-1.2.6.2, directory-1.2.5.1, directory-1.2.5.0,
directory-1.2.4.0, directory-1.2.3.1, directory-1.2.3.0, directory-1.2.2.1,
directory-1.2.2.0, directory-1.2.1.0, directory-1.2.0.1, directory-1.2.0.0,
directory-1.1.0.2, directory-1.1.0.1, directory-1.1.0.0, directory-1.0.1.2,
directory-1.0.1.1, directory-1.0.1.0, directory-1.0.0.3, directory-1.0.0.0,
directory-1.2.6.1 (has the same characteristics that caused the previous
version to fail: excluded by constraint '>=1.3.8.0' from 'playground')
[__5] fail (backjumping, conflict set: directory, playground, unix)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: directory, unix, playground,
unix-compat, warp, unix-compat:portable, scotty
Try running with --minimize-conflict-set to improve the error message.
How can I resolve this dependency conflict?
What this says:
playground-0.1.0.0 depends on directory >= 1.3.8.0
directory-1.3.8.0 is the only apparent solution to directory >= 1.3.8.0
directory-1.3.8.0 depends on unix >= 2.8.0 && <2.9
we already committed to unix==2.7.3, which does not satisfy that constraint
One thing you could try, therefore, is to give it a hint that you want to pick a newer unix, by adding a top-level constraint:
% cabal build --constraint `unix >=2.8.0 && <2.9`
Top-level constraints are "available" earlier than constraints found via searching for dependencies, and so can constrain earlier choices better. (I believe this property -- that constraints get solved and committed to in some not-totally-user-visible order -- is to make the dependency resolution algorithm more efficient. Bummer.)
I have a minimal example project:
Test
Test
Test.hs
Test.cabal
Test.hs contains an empty module Test.Test. The contents of Test.cabal are as follows:
name: Test
version: 0.0.0
library
build-depends: base
exposed-modules: Test.Test
Running cabal build fails with a long, confusing error message (copied below) unless I add cabal-version: 2.2 to the cabal file. Higher than 2.2 works as well but lower versions result in a similar error. My cabal version is 3.2. Why does the build fail unless I specify a cabal version and why are versions lower than 2.2 not sufficient?
The error message that I get without specifying cabal version is as follows:
Resolving dependencies...
cabal.exe: Could not resolve dependencies:
[__0] trying: Test-0.0.0 (user goal)
[__1] next goal: Test:setup.Cabal (dependency of Test)
[__1] rejecting: Test:setup.Cabal-3.2.0.0/installed-3.2.0.0 (conflict: Test =>
Test:setup.Cabal>=0 && <1.25)
[__1] skipping: Test:setup.Cabal-3.6.3.0, Test:setup.Cabal-3.6.2.0,
Test:setup.Cabal-3.6.1.0, Test:setup.Cabal-3.6.0.0, Test:setup.Cabal-3.4.1.0,
Test:setup.Cabal-3.4.0.0, Test:setup.Cabal-3.2.1.0, Test:setup.Cabal-3.2.0.0,
Test:setup.Cabal-3.0.2.0, Test:setup.Cabal-3.0.1.0, Test:setup.Cabal-3.0.0.0,
Test:setup.Cabal-2.4.1.0, Test:setup.Cabal-2.4.0.1, Test:setup.Cabal-2.4.0.0,
Test:setup.Cabal-2.2.0.1, Test:setup.Cabal-2.2.0.0, Test:setup.Cabal-2.0.1.1,
Test:setup.Cabal-2.0.1.0, Test:setup.Cabal-2.0.0.2 (has the same
characteristics that caused the previous version to fail: excluded by
constraint '>=0 && <1.25' from 'Test')
[__1] rejecting: Test:setup.Cabal-1.24.2.0, Test:setup.Cabal-1.24.0.0,
Test:setup.Cabal-1.22.8.0, Test:setup.Cabal-1.22.7.0,
Test:setup.Cabal-1.22.6.0, Test:setup.Cabal-1.22.5.0,
Test:setup.Cabal-1.22.4.0, Test:setup.Cabal-1.22.3.0,
Test:setup.Cabal-1.22.2.0, Test:setup.Cabal-1.22.1.1,
Test:setup.Cabal-1.22.1.0, Test:setup.Cabal-1.22.0.0,
Test:setup.Cabal-1.20.0.4, Test:setup.Cabal-1.20.0.3,
Test:setup.Cabal-1.20.0.2, Test:setup.Cabal-1.20.0.1,
Test:setup.Cabal-1.20.0.0, Test:setup.Cabal-1.18.1.7,
Test:setup.Cabal-1.18.1.6, Test:setup.Cabal-1.18.1.5,
Test:setup.Cabal-1.18.1.4, Test:setup.Cabal-1.18.1.3,
Test:setup.Cabal-1.18.1.2, Test:setup.Cabal-1.18.1.1, Test:setup.Cabal-1.18.1,
Test:setup.Cabal-1.18.0, Test:setup.Cabal-1.16.0.3, Test:setup.Cabal-1.16.0.2,
Test:setup.Cabal-1.16.0.1, Test:setup.Cabal-1.16.0, Test:setup.Cabal-1.14.0,
Test:setup.Cabal-1.12.0, Test:setup.Cabal-1.10.2.0, Test:setup.Cabal-1.10.1.0,
Test:setup.Cabal-1.10.0.0, Test:setup.Cabal-1.8.0.6, Test:setup.Cabal-1.8.0.4,
Test:setup.Cabal-1.8.0.2, Test:setup.Cabal-1.6.0.3, Test:setup.Cabal-1.6.0.2,
Test:setup.Cabal-1.6.0.1, Test:setup.Cabal-1.4.0.2, Test:setup.Cabal-1.4.0.1,
Test:setup.Cabal-1.4.0.0, Test:setup.Cabal-1.2.4.0, Test:setup.Cabal-1.2.3.0,
Test:setup.Cabal-1.2.2.0, Test:setup.Cabal-1.2.1, Test:setup.Cabal-1.1.6,
Test:setup.Cabal-1.24.1.0 (constraint from minimum version of Cabal used by
Setup.hs requires >=3.2)
[__1] fail (backjumping, conflict set: Test, Test:setup.Cabal)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: Test:setup.Cabal, Test
I am trying to install gloss but, I dont know why ghci doesn't find the modules.
When I do cabal install gloss it says:
Up to date
Warning: You asked to install executables, but there are no executables in
target: gloss. Perhaps you want to use --lib to install libraries instead.
When I do cabal install -lib gloss it gives me thies error:
Resolving dependencies...
cabal.exe: Could not resolve dependencies:
[__0] trying: bytestring-0.11.0.0 (user goal)
[__1] next goal: directory (user goal)
[__1] rejecting: directory-1.3.6.1 (constraint from user target requires
==1.3.6.0)
[__1] trying: directory-1.3.6.0/installed-1.3.6.0
[__2] next goal: Win32 (dependency of directory)
[__2] rejecting: Win32-2.6.1.0/installed-2.6.1.0 (conflict:
bytestring==0.11.0.0, Win32 => bytestring==0.10.10.0/installed-0.10.10.0)
[__2] rejecting: Win32-2.10.1.0, Win32-2.10.0.0, Win32-2.9.0.0, Win32-2.8.5.0,
Win32-2.8.4.0, Win32-2.8.3.0, Win32-2.8.2.0, Win32-2.8.1.0, Win32-2.8.0.0,
Win32-2.7.0.0, Win32-2.6.2.0, Win32-2.6.1.0, Win32-2.6.0.0, Win32-2.5.4.1,
Win32-2.5.3.0, Win32-2.5.2.0, Win32-2.5.1.0, Win32-2.5.0.0, Win32-2.4.0.0,
Win32-2.3.1.1, Win32-2.3.1.0, Win32-2.3.0.2, Win32-2.3.0.1, Win32-2.3.0.0,
Win32-2.2.2.0, Win32-2.2.1.0, Win32-2.2.0.2, Win32-2.2.0.1, Win32-2.2.0.0,
Win32-2.1.0.0, Win32-2.1, Win32-2.5.4.0 (conflict: directory =>
Win32==2.6.1.0/installed-2.6.1.0)
[__2] fail (backjumping, conflict set: Win32, bytestring, directory)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: ghc, bytestring, Win32, directory
Try running with --minimize-conflict-set to improve the error message.
This is very strange because the firs time I used this command it worked perfectly but then when I tried to do on ghci ´´´import ...´´´ it sayd: Module not found.
I have tried other modules and it gives me the same error. I thought that the issue could be that ghc is not able to search in the cabal folder where the packages are saved but I am no longer sure.
How can I fix this? Thanks
I recently got into developing with reflex-platform, with some extra configuration similar to what is described in the excellent reflex-project-skeleton.
Now I am having a package conflict that I am unable to resolve.
I use the same cabal script as reflex-project-skeleton, which invokes nix-shell in non-interactive mode with a cabal command.
If I try
./cabal new-build --allow-newer all
I get
these derivations will be built:
/nix/store/d6ji516i7pry5l6gv18y6hpj9k1bvgg5-heist-1.0.1.0.drv
/nix/store/zj1clks7mzq8gn91ahhwa3nvpi5rwra9-snap-1.0.0.2.drv
/nix/store/mx861972jnjabn7yxyr3y3q1yhf25jfq-snaplet-acid-state-0.2.7.drv
/nix/store/grhp4dhavmpi6bgns5a6vdzg8ny2bsf8-hoogle-local-0.1.drv
/nix/store/y3sszsj58f6ad3r06540w0mlr1pncd59-ghc-8.0.2-with-packages.drv
...
Configuring heist-1.0.1.0...
Setup: Encountered missing dependencies:
aeson >=0.6 && <1.2
builder for '/nix/store/d6ji516i7pry5l6gv18y6hpj9k1bvgg5-heist-1.0.1.0.drv' failed with exit code 1
cannot build derivation '/nix/store/y3sszsj58f6ad3r06540w0mlr1pncd59-ghc-8.0.2-with-packages.drv': 1 dependencies couldn't be built
The offending package appears to be snaplet-acid-state, so I tried installing it from inside the nix-shell:
cabal install snaplet-acid-state
Resolving dependencies...
cabal: Could not resolve dependencies:
trying: snaplet-acid-state-0.2.7 (user goal)
trying: base-4.9.1.0/installed-4.9... (dependency of snaplet-acid-state-0.2.7)
next goal: mtl (dependency of snaplet-acid-state-0.2.7)
rejecting: mtl-2.2.1/installed-BLK... (conflict: mtl =>
transformers==0.5.2.0/installed-0.5..., snaplet-acid-state =>
transformers>=0.3.0.0 && <0.5)
trying: mtl-2.2.2
next goal: transformers (dependency of snaplet-acid-state-0.2.7)
rejecting: transformers-0.5.2.0/installed-0.5..., transformers-0.5.5.0,
transformers-0.5.4.0, transformers-0.5.2.0, transformers-0.5.1.0,
transformers-0.5.0.1, transformers-0.5.0.0 (conflict: snaplet-acid-state =>
transformers>=0.3.0.0 && <0.5)
rejecting: transformers-0.4.3.0, transformers-0.4.2.0 (conflict:
base==4.9.1.0/installed-4.9..., transformers => base>=2 && <4.9)
rejecting: transformers-0.4.1.0 (conflict: base==4.9.1.0/installed-4.9...,
transformers => base>=2 && <4.8 || >=1.0 && <2)
rejecting: transformers-0.3.0.0 (conflict: mtl => transformers>=0.4 && <0.6)
rejecting: transformers-0.2.2.1, transformers-0.2.1.0, transformers-0.2.0.0,
transformers-0.1.4.0, transformers-0.1.3.0, transformers-0.1.1.0,
transformers-0.1.0.1, transformers-0.0.1.0, transformers-0.0.0.0,
transformers-0.5.3.1, transformers-0.5.3.0, transformers-0.5.0.2 (conflict:
snaplet-acid-state => transformers>=0.3.0.0 && <0.5)
rejecting: transformers-0.4.0.0 (conflict: base==4.9.1.0/installed-4.9...,
transformers => base>=2 && <4.8 || >=1.0 && <2)
rejecting: transformers-0.2.2.0, transformers-0.1.0.0 (conflict:
snaplet-acid-state => transformers>=0.3.0.0 && <0.5)
After searching the rest of the dependency tree exhaustively, these were the
goals I've had most trouble fulfilling: transformers, snap, base,
snaplet-acid-state, mtl
Tried specifying a version constraint in the cabal file, among other things, but to no effect.
Any clues? I'm not even sure what the exact issue is. Why is aeson failing to install in the first instance, and there is a conflict between snaplet-acid-state and mtl in the second?
What happens with this cabal2nix workflow is that basically the dependency solver is forced to only consider the packages that have been provided by Nixpkgs, or in this case reflex-platform + Nixpkgs. By taking away the freedom to pick one of multiple versions, the Cabal dependency solver is reduced to a dependency checker.
Now, if the version bound is too strict, you can consider what is called 'jailbreaking' in Nixpkgs: removing all version bounds from the cabal file. The other option is to change package versions.
Gabriel Gonzalez has written a good explanation of version management with Nixpkgs' Haskell infrastructure. You may also check out this thread. It's a bit verbose, but it discusses the callHackage and callCabal2nix functions that are quite helpful.
I'm trying to add timerep onto an existing application. I can't get it to resolve my dependencies. It looks like it is using the globally installed version of time == 1.4.2, when >= 1.5 would be ideal for my application.
How can I get cabal to use time 1.5? I've poked through unix, tls, process, timerep, and they all seem like they would work fine if it would just use time >= 1.5.
Here's the error:
serials> cabal install --only-dependencies
Resolving dependencies...
cabal: Could not resolve dependencies:
trying: serials-0.1.0.2 (user goal)
trying: mandrill-0.2.2.0 (dependency of serials-0.1.0.2)
trying: http-client-tls-0.2.2 (dependency of mandrill-0.2.2.0)
trying: tls-1.2.17 (dependency of http-client-tls-0.2.2)
trying: x509-validation-1.5.2 (dependency of tls-1.2.17)
trying: process-1.2.0.0/installed-487... (dependency of x509-validation-1.5.2)
next goal: unix (dependency of process-1.2.0.0/installed-487...)
rejecting: unix-2.7.0.1/installed-299... (conflict: unix =>
time==1.4.2/installed-bf9..., serials => time>=1.5)
rejecting: unix-2.7.1.0, 2.7.0.1, 2.7.0.0, 2.6.0.1, 2.6.0.0, 2.5.1.1, 2.5.1.0,
2.5.0.0, 2.4.2.0, 2.4.1.0, 2.4.0.2, 2.4.0.1, 2.4.0.0, 2.3.2.0, 2.3.1.0,
2.3.0.0, 2.2.0.0, 2.0 (conflict: process => unix==2.7.0.1/installed-299...)
Dependency tree exhaustively searched.
Cabal file:
-- Initial serials.cabal generated by cabal init. For further
-- documentation, see http://haskell.org/cabal/users-guide/
name: serials
version: 0.1.0.2
synopsis: serials
description: serials
license: MIT
license-file: LICENSE
author: Sean Hess
maintainer: Sean Hess
-- copyright:
category: Web Scraper
build-type: Simple
extra-source-files: README.md
cabal-version: >=1.10
Source-repository head
type: git
location: git#github.com:seanhess/serials.git
executable serials
main-is: Main.hs
hs-source-dirs: server
ghc-options: -fcontext-stack=36
-- other-modules:
-- other-extensions:
default-language: Haskell2010
build-depends:
base >=4.7 && <5,
tagsoup,
text,
scalpel,
containers,
network-uri,
monad-loops,
wreq,
lens,
bytestring,
parsec,
utf8-string,
tagsoup,
xml,
feed,
regex-pcre,
aeson,
network,
wai,
wai-extra,
wai-cors,
wai-middleware-static,
warp,
servant-server >= 0.4,
rethinkdb >= 1.16,
transformers,
either,
unordered-containers,
mtl,
http-types,
safe,
hashable,
resource-pool,
time >= 1.5,
pooled-io,
shelly,
string-conversions,
bcrypt,
random,
jwt,
cookie,
entropy,
mandrill == 0.2.2.0,
email-validate,
blaze-markup,
blaze-html,
iso8601-time,
scotty == 0.10.0,
timerep >= 2.0.0
It is difficult for cabal-install to produce a complete description of the mutual incompatibilities of an installation problem. It instead decides to print the first path to failure.
However, it prints Dependency tree exhaustively searched. which indicates that there actually is no solution to the given problem.
One thing that often helps is to look at the choices cabal-install has made, find one that seems suboptimal, and then add an explicit constraint to change that. This may result in a better error message.
Let's try [note that I'm not sure if I have exactly the same package DB as you have, so it may produce different results on your system].
You had (modulo hashes of installed packages):
$ cabal install --only-dependencies
Resolving dependencies...
cabal: Could not resolve dependencies:
trying: serials-0.1.0.2 (user goal)
trying: mandrill-0.2.2.0 (dependency of serials-0.1.0.2)
trying: http-client-tls-0.2.2 (dependency of mandrill-0.2.2.0)
trying: tls-1.2.17 (dependency of http-client-tls-0.2.2)
trying: x509-validation-1.5.2 (dependency of tls-1.2.17)
trying: process-1.2.0.0/installed-06c... (dependency of x509-validation-1.5.2)
next goal: unix (dependency of process-1.2.0.0/installed-06c...)
rejecting: unix-2.7.0.1/installed-f86... (conflict: unix =>
time==1.4.2/installed-9b3..., serials => time>=1.5)
rejecting: unix-2.7.1.0, 2.7.0.1, 2.7.0.0, 2.6.0.1, 2.6.0.0, 2.5.1.1, 2.5.1.0,
2.5.0.0, 2.4.2.0, 2.4.1.0, 2.4.0.2, 2.4.0.1, 2.4.0.0, 2.3.2.0, 2.3.1.0,
2.3.0.0, 2.2.0.0, 2.0 (conflict: process => unix==2.7.0.1/installed-f86...)
Dependency tree exhaustively searched.
Looking through this, the error occurs with unix, which is a dependency of process. So the installed instance of process being chosen leads to trouble. So what if we disallow choosing that instance of process?
$ cabal install --only-dependencies --constraint="process source"
Resolving dependencies...
cabal: Could not resolve dependencies:
trying: serials-0.1.0.2 (user goal)
next goal: time (dependency of serials-0.1.0.2)
rejecting: time-1.4.2/installed-9b3... (conflict: serials => time>=1.5)
trying: time-1.5.0.1
next goal: rethinkdb (dependency of serials-0.1.0.2)
rejecting: rethinkdb-1.16.0.0 (conflict: time==1.5.0.1, rethinkdb =>
time==1.4.*)
rejecting: rethinkdb-1.15.2.1, 1.15.2.0, 1.15.1.0, 1.15.0.0, 1.8.0.5, 1.8.0.4,
1.8.0.3, 1.8.0.2, 1.8.0.1, 1.8.0.0, 0.1.0.0 (conflict: serials =>
rethinkdb>=1.16)
Dependency tree exhaustively searched.
Aha! So rethinkdb, which is a direct dependency of serials, has an explicit dependency on time == 1.4.*. This is in direct conflict with the dependency of serials on time >= 1.5.
This is not easy to fix. You either need to make rethinkdb work with the newer time library, or serials with the older.
We enter the realm of speculation now: It is possible, but not guaranteed, that rethinkdb actually works with a newer version of time. We can try to instruct cabal-install to consider such install plans:
$ cabal install --only-dependencies --allow-newer=time
This actually yields an install plan on my machine. I have not tried building it, and I don't know whether it works. But it may be worth a try.