stack ghci doesn't work while stack build does

[Fuuzetsu]

I have a project here where stack build works happily but stack ghci does not. I would expect that if stack build can build the project, stack ghci should have no problem giving me a repl. I inline the description of the particular issue from the mailing list:

We have a test with

#include <Rversion.h>

This is provided by the R language. On my system, the R/lib is in a
non-standard location.

Nevertheless, my CPP/gcc are wrapped in a script which uses NIX_LDFLAGS
env var which amongst other things has
-L/nix/store/jvvpcckvzybr7y0zmj1x5psb5sy7ipa7-R-3.2.1/lib

So everything works when I stack build.

But when I try to use ‘stack ghci’ on the project, I get

     fatal error: Rversion.h: No such file or directory
     #include <Rversion.h>

Is there anything I can do so ‘stack ghci’ just works like ‘stack build’
does?

In my case it is about CPP being used but this is a bit of a general question.

Using stack from a day or so old git checkout.

[rrnewton]

The LVish project is also one where stack build works but stack ghci fails on stack 0.1.2.0. In its case it fails with the following on Mac OS:

$ stack ghci
Configuring GHCi with the following packages: concurrent-skiplist, lvish, par-classes, par-collections, test-par-collections, par-mergesort, par-transformers
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
<command line>: cannot satisfy -package criterion
    (use -v for more information)

That looks like maybe a mixup with the dependencies of the different targets. I.e. criterion should only be required for benchmark targets, and thus wasn't built by stack buildalone.

On a related note, I also think it is too bad that stack ghci stops working when a build error breaks stack build. That is, a lot of the time I want to poke around in the repl, or at least use the dependencies when I just broke the build. For example, with stack itself, if you put garbage in a module (say, Main.hs for the executable), then:

$ stack ghci
Configuring GHCi with the following packages: stack
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
<command line>: cannot satisfy -package stack
    (use -v for more information)

[Fuuzetsu]

Yes, test/bench dependencies are another thing that doesn't work out of the box in stack ghci though I can somewhat forgive that seeing as the default is ‘load everything’. Still, it could be smarter.

[duplode]

That looks like maybe a mixup with the dependencies of the different targets. I.e. criterion should only be required for benchmark targets, and thus wasn't built by stack buildalone.

I met the same issue when trying to use my GitHub fork of zip-conduit as a dependency, like this:

# stack.yaml snippet.
packages:
- '.'
- location:
    git: https://github.com/duplode/zip-conduit
    commit: 1eefc8bd91d5f38b760bce1fb8dd16d6e05a671d
    extra-dep: true

In such a situation one would never be interested in running the benchmarks of zip-conduit, as it is just another dependency. Adding the extra-dep flag didn't help.

[duplode]

Adding the extra-dep flag didn't help.

Never mind my complaint above - the extra-dep field is wrongly indented. Still, my (non-)issue has lead me to wonder whether it would be appropriate to fix this with a treat-as-dep-in-ghci field (ideally with a less clunky name). By the way, the "load everything in GHCi" behaviour is, as implied by Fuuzetsu's comment, by design. See #130 for the rationale.

[chrisdone]

Continuing test/bench dependencies in #629 with PR #726.

[chrisdone]

@Fuuzetsu Do you have a minimal test project I can clone to reproduce and fix?

[mitchellwrosen]

@chrisdone I can describe how to make one, it's simple:

$ stack new
$ vi new-template.cabal
-- add 'tasty' dependency to new-template-test suite
$ stack build
$ stack ghci
Configuring GHCi with the following packages: new-template
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
<command line>: cannot satisfy -package tasty
    (use -v for more information)

Workaround:

$ stack test
$ stack ghci

[chrisdone]

I think @mitchellwrosen your problem differs to that of @Fuuzetsu.

[Fuuzetsu]

Yes, it does. I'm a bit constrained on time right now but maybe I can produce something soon, sorry for delays.

[mitchellwrosen]

Oops, I was looking at @rrnewton's comment. Sorry!

[rpglover64]

I think I'm having this same issue... to reproduce:

git clone https://github.com/Gabriel439/Haskell-Turtle-Library.git
cd Haskell-Turtle-Library
git checkout da98f7e
stack init
stack build
stack ghci

Expected behavior: ghci is launched with the project loaded
Actual behavior:

Configuring GHCi with the following packages: turtle
GHCi, version 7.10.2: http://www.haskell.org/ghc/  :? for help
<command line>: cannot satisfy -package criterion-1.1.0.0
    (use -v for more information)

[chrisdone]

@rpglover64 Are you on a recent stack?

[rpglover64]

Version 0.1.3.0, Git revision 385332d

[chrisdone]

Your problem's been fixed since then, try latest master. :-)

[rpglover64]

I'm almost annoyed at how fast stack is moving... On the other hand, my issues are getting fixed. 😃

Thanks.

[ezyang]

Hi guys, I've opened a GHC ticket to track this issue. https://ghc.haskell.org/trac/ghc/ticket/10827

[chrisdone]

Thanks @ezyang!

[mgsloan]

I'm going to close this issue, since it's old and the GHCi support has had lots of improvements since then. Feel free to open additional issues with concrete cases of the GHCI support being problematic.

Also, I've added some warnings which hopefully will make it clearer why things don't work, at least in the presence of extension flags: #1270