What do I need to do to initialize a GHCJS project using Haskell Stack?
Following the stack documentation I am trying to initialize a GHCJS project so that I can compile Haskell code to JavaScript.
After doing stack templates I see there is a GHCJS template
ghcjs - Haskell to JavaScript compiler, based on GHC
When I try using the new command with this template like this:
stack new ghcjsSetup ghcjs
I get this error message:
Downloading template "ghcjs" to create project "ghcjsSetup" in ghcjsSetup/ ...
The following parameters were needed by the template but not provided: author-email, author-name, category, copyright, github-username
You can provide them in /home/u/.stack/config.yaml, like this:
templates:
params:
author-email: value
author-name: value
category: value
copyright: value
github-username: value
Or you can pass each one as parameters like this:
stack new ghcjsSetup ghcjs -p "author-email:value" -p "author-name:value" -p "category:value" -p "copyright:value" -p "github-username:value"
Looking for .cabal or package.yaml files to use to init the project.
Using cabal packages:
- ghcjsSetup/ghcjsSetup.cabal
Selecting the best among 11 snapshots...
* Partially matches lts-9.11
ghcjs-base not found
- ghcjsSetup requires -any
Downloaded nightly-2017-11-01 build plan.
Unable to parse cabal file: FromString "This package requires at least Cabal version 2.0" Nothing
I've got the same error recently. Apparently you've got an old version of stack. You need to upgrade it to version >= 1.5.1. This error occurs because of some file format changes in Cabal ver. 2.0 as I think.
Related
I want to install the Haskell libary hip from https://hackage.haskell.org/package/hip by using stack. This does not work, because stack seems to not being able to install dependencies.
I have stack freshly installed by curl -sSL https://get.haskellstack.org/ | sh, and stack --version gives me
Version 1.9.3, Git revision 40cf7b37526b86d1676da82167ea8758a854953b (6211 commits) x86_64 hpack-0.31.1
I have tried several things like another resolver, reinstalling different versions of stack, ghc or cabal.
I have tried stack new test, and inside the test folder, i wrote stack install hip.
I got the following error:
Error: While constructing the build plan, the following exceptions were
encountered:
In the dependencies for hip-1.5.3.0:
Chart must match >=1.5, but the stack configuration has no specified
version (latest matching version is 1.9)
Chart-diagrams must match >=1.5, but the stack configuration has no
specified version (latest matching version is 1.9)
needed since hip is a build target.
Some different approaches to resolving this:
* Consider trying 'stack solver', which uses the cabal-install solver to
attempt to find some working build configuration. This can be convenient
when dealing with many complicated constraint errors, but results may be
unpredictable.
* Recommended action: try adding the following to your extra-deps
in /home/jarek/Desktop/test/stack.yaml:
Chart-1.9#sha256:f41568b6b3704f66c2ec163295b430ab7d798f91de426c2d5aba747d1135cd9b
Chart-diagrams-1.9#sha256:cdd0c22d730e507f9644e690833096ee127302b5ff5e1571f6def419160a2642
Plan construction failed.
I expect something like:
Building dependencies...
Installing Chart-1.9
...
...
...
hip successfully installed.
Please tell me if i did not provide all infos necessary for you to help me with my problem.
Installing with the resolver lts-7.5 works.
Why not do what stack recommended?
Recommended action: try adding the following to your extra-deps
in /home/jarek/Desktop/test/stack.yaml:
Chart-1.9#sha256:f41568b6b3704f66c2ec163295b430ab7d798f91de426c2d5aba747d1135cd9b
Chart-diagrams-1.9#sha256:cdd0c22d730e507f9644e690833096ee127302b5ff5e1571f6def419160a
It's the easiest way to accomplish your goal.
Update: lts-10.10 is the most recent resolver to include hip. If you update your stack.yaml to use lts-10.10 and add hip in your .cabal file, you should be good to go.
I'm trying to use the excellent AWS SDK amazonka in the backend portion of an API built using the equally excellent web framework yesod, but I am having great difficulty getting the dependencies for these two libraries to work together.
I started the scaffolded yesod project with
stack new my-project yesod-mongo
which populated my cabal file with the most recent version of yesod (1.6.0). Naively adding the dependencies amazonka-core and amazonka-ssm (for example) to my cabal file comes back with
Error: While constructing the build plan, the following exceptions were encountered:
In the dependencies for my-project-0.0.0:
amazonka-core must match -any, but the stack configuration has no specified version
(latest matching version is 1.5.0)
amazonka-ssm must match -any, but the stack configuration has no specified version
(latest matching version is 1.5.0)
needed since my-project is a build target.
As suggested, I tried adding amazonka-core-1.5.0 and amazonka-ssm-1.5.0 to my stack.yaml file under extra-deps, but this doesn't work:
Warning: WARNING: /home/ubuntu/my-project/my-project.cabal was modified manually.
Ignoring package.yaml in favor of cabal file. If you want to use package.yaml
instead of the cabal file, then please delete the cabal file.
Error: While constructing the build plan, the following exceptions were encountered:
In the dependencies for amazonka-core-1.5.0:
conduit-1.3.0.2 from stack configuration does not match >=1.1 && <1.3 (latest
matching version is 1.2.13.1)
needed due to my-project-0.0.0 -> amazonka-core-1.5.0
After a bit of digging, it seems that the snapshot that the yesod template was built off of is lts-11.6, but the most recent snapshot that the amazonka library is included in is lts-10.9. So, I tried building the project again from the yesod-mongo template, but this time specifying an older snapshot:
ubuntu:~$ stack new my-project yesod-mongo --resolver lts-10.9
Downloading template "yesod-mongo" to create project "my-project" in my-project/ ...
Looking for .cabal or package.yaml files to use to init the project.
Using cabal packages:
- my-project/
Selected resolver: lts-10.9
Resolver 'lts-10.9' does not have all the packages to match your requirements.
classy-prelude version 1.3.1 found
- my-project requires ==1.4.*
classy-prelude-conduit version 1.3.1 found
- my-project requires ==1.4.*
classy-prelude-yesod version 1.3.1 found
- my-project requires ==1.4.*
http-conduit version 2.2.4 found
- my-project requires ==2.3.*
persistent version 2.7.1 found
- my-project requires ==2.8.*
persistent-mongoDB version 2.6.0 found
- my-project requires ==2.8.*
yesod version 1.4.5 found
- my-project requires ==1.6.*
yesod-auth version 1.4.21 found
- my-project requires ==1.6.*
yesod-core version 1.4.37.3 found
- my-project requires ==1.6.*
yesod-form version 1.4.16 found
- my-project requires ==1.6.*
yesod-static version 1.5.3.1 found
- my-project requires ==1.6.*
Using package flags:
- my-project: dev = False, library-only = False
Now I am at a loss and more than a little frustrated. It seems like perhaps the template is ignoring the snapshot specification. So, my question:
Is there a way to build the scaffolded site from a template that uses a specific snapshot to fill in the cabal and stack.yaml files? Is there anything else I can do to get this to work?
Happy to provide more information if it's helpful.
Edit: I also tried bumping down the versions of the packages in the above snippet, and while this solves the issue of building dependencies, now the scaffolded site doesn't compile (presumably because things have changed in a meaningful way from yesod-1.4.5 to yesod-1.6.0).
Unfortunately you can't use Commercial Haskell's stack templates with yesod and amazonka as of now. The reasons being:
There was a recent conduit rewrite in version 1.3
Some breaking changes were introduced in recent Yesod 1.6 which depends on conduit >= 1.3
Amazonka doesn't work with recent version of conduit
The only way for you to get it working is switching back to old version of stack templates (those templates which actually worked with stackage resolver 10.9) and then using that to create a new project. Fortunately, Stack supports custom stack templates:
$ stack new my-project https://raw.githubusercontent.com/github-user-id/stack-templates/master/my-template.hsfiles
In my project I'm using a library that depends on two C packages: sqlite3 and libsqlite3-dev. I installed them using apt-get install and then build the project with stack build and everything works fine.
However, the stack build fails when used with nix with error message "* Missing C library: sqlite3". I understand that the nix enviroment is isolated and that I have to install it there. I tried installing it using nix-env -i sqlite3 but it returns error: selector ‘sqlite3’ matches no derivations. It looks it is missing in the channel (using nixpkgs-unstable).
Is there any way how use to use C libraries with stack and nix that are missing in the channel?
I am using nix because of a bug in IHaskell, otherwise I would be fine with just stack.
You need to add sqlite to your packages section in stack.yaml as follows:
nix:
enable: false
packages:
- sqlite
The enable: false is there so that Stack doesn't try to build with Nix by default. If you want this behaviour, remove that line.
There's an example of this here.
I'm trying to setup a new project using the nightly-2017-08-17 snapshot
stack new test --resolver nightly-2017-08-17
However this gives the following error:
Downloading template "new-template" to create project "test" in test/ ...
Looking for .cabal or package.yaml files to use to init the project.
Using cabal packages:
- test/test.cabal
Selected resolver: nightly-2017-08-17
Unable to parse cabal file: FromString "This package requires at least Cabal version 2.0" Nothing
Cabal is in its latest version:
stack setup --upgrade-cabal
Currently installed Cabal is 2.0.0.2, newest is 2.0.0.2. I'm not upgrading Cabal.
stack will use a sandboxed GHC it installed
For more information on paths, see 'stack path' and 'stack exec env'
To use this GHC and packages outside of a project, consider using:
stack ghc, stack ghci, stack runghc, or stack exec
Is this not the correct way of selecting this nightly snapshot with stack or is this a bug in the tool?
Cabal's file format has changed in the 2.0 release of it (likely because of backpack). You have to use Stack version >= 1.5.1 which bypasses this error. A proper fix for this will be likely released in the next version of Stack. IIRC, the fix is already in the master brach of the stack - so the upgrade via --source-only willl also work for you.
You can read the changelog here to know more information about it.
I'm trying to set up Hakyll on a fresh Ubuntu 16.04 instance, but I can't seem to get the Stack-based setup instructions right.
Starting out with stack install hakyll, I get:
Error: While constructing the build plan, the following exceptions were encountered:
In the dependencies for hakyll-4.9.3.0:
http-conduit-2.1.11 must match >=2.2 && <2.3 (latest applicable is 2.2.3)
Plan construction failed.
I got a similar error when tying to stack-install http-conduit-2.1.11, this time with:
Error: While constructing the build plan, the following exceptions were encountered:
In the dependencies for http-conduit-2.2.3:
http-client-0.4.31.2 must match >=0.5 && <0.6 (latest applicable is 0.5.5)
http-client-tls-0.2.4.1 must match >=0.3 && <0.4 (latest applicable is 0.3.3.1)
Plan construction failed.
After resolving dependencies for this (also using Stack), I tried once again to stack install http-conduit-2.1.11, but I once again got the same dependency error.
The packages http-client-0.4.31.2 and http-client-tls-0.2.4.1 appear in my ~/.stack/precompiled/x86_64-linux/ghc-8.0.1/1.24.0.0/, which isn't explicitly in my $PATH, however that feels like an extremely hacky solution, and I haven't found any documentation recommending this approach.
How can I correctly install Hakyll on my machine?
Dependency management with stack is meant to be reproducible and declarative, that means that a stack project will only compile once all dependencies are recorded in the .cabal file(s) of the project and once the stack.yaml of the project defines versions for these dependencies either in the resolver or the extra-deps section.
Your confusion seems to stem from a misunderstanding of what stack install does. The command line help has this to say about it:
build Build the package(s) in this directory/configuration
install Shortcut for 'build --copy-bins'
...
--[no-]copy-bins Enable/disable copying binaries to the local-bin-path
(see 'stack path')
stack install does not save any dependencies.
So the proper way of making hakyll available as a dependency to your code is:
Create a proper stack project with stack init if you already have a Cabal package, or stack new if you don't.
Add hakyll to the library or executable build-depends in your .cabal file.
Attempt to stack build and follow the instructions in any error messages until all issues are resolved.
A simpler solution than #sjakobi's in this case was to specify a resolver as a command line option when starting a new Stack project:
stack install hakyll --resolver=5.11 --install-ghc