This may be caused by some cabal.project lying around (e.g., in the directory you are in when you are installing, but also in any parent directory) or by .ghc.environment.arch-os-version files lying around https://ghc.gitlab.haskell.org/ghc/doc/users_guide/packages.html#package-env... which is likely if you indeed installed whole packages, and not just executables from the packages (`cabal install` only installs executables). If the problem persists please file a ticket on cabal github bug tracker. BTW, I haven't received your email, but only the response from Tom. Nothing in the spam folder, either. Strange. On Thu, Sep 15, 2022 at 5:32 PM Tom Ellis wrote:

On Thu, Sep 15, 2022 at 05:23:10PM +0200, Volker Wysk wrote:

...

I've lately set up the Haskell environment on my Linux box, with no problems. Then I have installed some packages with "cabal install", again without problems. But now I'm trying to install another package and I get a dependency conflict. It doesn't seem to matter which package I try to install:

This is quite weird, because neither directory nor ghc are dependencies of rfc5051.

As a first step, can you try the following and report back whether you successfully get to a GHCi a prompt?

$ cabal repl -z --build-depends rfc5051

...

desktop ~ $ cabal install rfc5051 Resolving dependencies... cabal: Could not resolve dependencies: [__0] next goal: directory (user goal) [__0] rejecting: directory-1.3.8.0 (constraint from user target requires ==1.3.7.1) [__0] trying: directory-1.3.7.1 [__1] next goal: ghc (user goal) [__1] rejecting: ghc-9.4.2, ghc-9.4.1, ghc-9.2.4, ghc-9.2.3, ghc-9.2.2, ghc-9.2.1, ghc-9.0.2, ghc-8.10.7, ghc-8.10.2, ghc-8.10.1 (constraint from user target requires ==8.8.4) [__1] rejecting: ghc-8.8.4/installed-8.8... (conflict: directory==1.3.7.1, ghc => directory==1.3.6.0/installed-1.3...) [__1] rejecting: ghc-8.8.3, ghc-8.8.1, ghc-8.6.5, ghc-8.6.4, ghc-8.6.1, ghc-8.4.4, ghc-8.4.3, ghc-8.4.1, ghc-8.2.2, ghc-8.2.1, ghc-9.2.3.20220620 (constraint from user target requires ==8.8.4) [__1] fail (backjumping, conflict set: directory, ghc) After searching the rest of the dependency tree exhaustively, these were the goals I've had most trouble fulfilling: directory, ghc

---

Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.

On Thu, Sep 15, 2022 at 06:09:33PM +0200, Volker Wysk wrote:

Am Donnerstag, dem 15.09.2022 um 17:47 +0200 schrieb Mikolaj Konarski:

...

This may be caused by some cabal.project lying around (e.g., in the directory you are in when you are installing, but also in any parent directory) or by .ghc.environment.arch-os-version files lying around

https://ghc.gitlab.haskell.org/ghc/doc/users_guide/packages.html#package-env...

I don't have a cabal.project or .ghc.environment.arch-os-version lying around. However, I've found ~/.ghc/x86_64-linux-8.8.4/environments/default, which contains this:

GHC 8.8.4 depends on directory 1.3.6.0, therefore the GHC API package, ghc, does too as mentioned in the original error message: [__1] rejecting: ghc-8.8.4/installed-8.8... (conflict: directory==1.3.7.1, ghc => directory==1.3.6.0/installed-1.3...) and can be verified at: https://gitlab.haskell.org/ghc/ghc/-/wikis/commentary/libraries/version-hist... However, you have got an environment file that requires ghc-8.8.4 and directory-1.3.7.1 at the same time. Something's funny about that because it's impossible to satisfy and I'm not sure how it could have happened in the first place. Perhaps some cabal expert can weigh in. Tom

clear-package-db global-package-db package-db /home/v/.cabal/store/ghc-8.8.4/package.db package-id ghc-8.8.4 package-id bytestring-0.10.10.1 package-id unix-2.7.3- f9e049162269c42fac796ce2193bc96fb95dfe3ac975de03338213cf0e37a14a package-id base-4.13.0.0 package-id time-1.12.1- 79940fa11921893814fd2d9a0f4653cb6d9b3a2de6720e03a14215ba5d4e06e7 package-id hpc-0.6.0.3 package-id filepath-1.4.2.1 package-id process-1.6.15.0- 0397a5aa0d99937f979c3ecfb8c3917000787735a4c430a5ee92c026f8987cf0 package-id array-0.5.4.0 package-id integer-gmp-1.0.2.0 package-id containers-0.6.2.1 package-id ghc-boot-8.8.4 package-id binary-0.8.7.0 package-id ghc-prim-0.5.3 package-id ghci-8.8.4 package-id rts package-id terminfo-0.4.1.4 package-id transformers-0.5.6.2 package-id deepseq-1.4.4.0 package-id ghc-boot-th-8.8.4 package-id pretty-1.1.3.6 package-id template-haskell-2.15.0.0 package-id directory-1.3.7.1- ada0557c8af940ba0586588eddbc02eb543cb70097182636c20a53c37f6c724e package-id text-1.2.4.0 package-id random-1.2.1.1- 96a066a3c9e6ce9db8a64c0229a4a92c26549367424a16852f798314b610d9ae package-id hsshellscript-3.5.0- d22730dc2a5e25b97ff191ad98a6a1517ff456eecf456231207a8e35d428732e

Am Freitag, dem 16.09.2022 um 08:38 +0100 schrieb Tom Ellis:

On Thu, Sep 15, 2022 at 05:33:06PM +0100, Tom Ellis wrote:

...

On Thu, Sep 15, 2022 at 06:09:33PM +0200, Volker Wysk wrote:

...

Am Donnerstag, dem 15.09.2022 um 17:47 +0200 schrieb Mikolaj Konarski:

...

This may be caused by some cabal.project lying around (e.g., in the directory you are in when you are installing, but also in any parent directory) or by .ghc.environment.arch-os-version files lying around

https://ghc.gitlab.haskell.org/ghc/doc/users_guide/packages.html#package-env...

I don't have a cabal.project or .ghc.environment.arch-os-version lying around. However, I've found ~/.ghc/x86_64-linux-8.8.4/environments/default, which contains this:

GHC 8.8.4 depends on directory 1.3.6.0, therefore the GHC API package, ghc, does too as mentioned in the original error message:

[__1] rejecting: ghc-8.8.4/installed-8.8... (conflict: directory==1.3.7.1, ghc => directory==1.3.6.0/installed-1.3...)

and can be verified at:

https://gitlab.haskell.org/ghc/ghc/-/wikis/commentary/libraries/version-hist...

However, you have got an environment file that requires ghc-8.8.4 and directory-1.3.7.1 at the same time. Something's funny about that because it's impossible to satisfy and I'm not sure how it could have happened in the first place. Perhaps some cabal expert can weigh in.

In the hope that a cabal expert can explain this behaviour I have opened as issue:

https://github.com/haskell/cabal/issues/8473

Thanks for that. But I'm switching to cabal ("cabal build") now, instead of my Makefile. Of course the problem should be minded, if it is a bug. However, I don't need that any longer. Cheers, Volker

On Thu, Sep 15, 2022 at 06:11:55PM +0200, Volker Wysk wrote:

Am Donnerstag, dem 15.09.2022 um 16:31 +0100 schrieb Tom Ellis:

...

On Thu, Sep 15, 2022 at 05:23:10PM +0200, Volker Wysk wrote:

...

I've lately set up the Haskell environment on my Linux box, with no problems. Then I have installed some packages with "cabal install", again without problems. But now I'm trying to install another package and I get a dependency conflict. It doesn't seem to matter which package I try to install:

This is quite weird, because neither directory nor ghc are dependencies of rfc5051.

As a first step, can you try the following and report back whether you successfully get to a GHCi a prompt?

$ cabal repl -z --build-depends rfc5051

This results in:

desktop ~ $ cabal repl -z --build-depends rfc5051 Resolving dependencies... Build profile: -w ghc-8.8.4 -O1 In order, the following will be built (use -v for more details): - rfc5051-0.2 (lib) (requires download & build) - fake-package-0 (lib) (first run) Downloading rfc5051-0.2 Downloaded rfc5051-0.2 Starting rfc5051-0.2 (lib) Building rfc5051-0.2 (lib) Installing rfc5051-0.2 (lib) Completed rfc5051-0.2 (lib) Configuring library for fake-package-0.. Preprocessing library for fake-package-0.. Warning: No exposed modules GHCi, version 8.8.4: https://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /tmp/cabal-repl.-17863/setcwd.ghci Prelude>

Looks good, doesn't it..?

Yes, so this means that the problem is indeed the ~/.ghc/x86_64-linux-8.8.4/environments/default that Mikolaj predicted and you confirmed in a sibling thread. I'm not sure what the suggested fix is. I find this part of the cabal command line API extremely inscrutable. Tom

The hex ID is an ABI hash. It is included for libraries installed by cabal, but not those that ship with ghc itself. On Thu, Sep 15, 2022 at 12:27 PM Volker Wysk wrote:

Am Donnerstag, dem 15.09.2022 um 17:17 +0100 schrieb Tom Ellis:

...

On Thu, Sep 15, 2022 at 06:11:55PM +0200, Volker Wysk wrote:

...

Am Donnerstag, dem 15.09.2022 um 16:31 +0100 schrieb Tom Ellis:

...

On Thu, Sep 15, 2022 at 05:23:10PM +0200, Volker Wysk wrote:

...

I've lately set up the Haskell environment on my Linux box, with no problems. Then I have installed some packages with "cabal install", again without problems. But now I'm trying to install another package and I get a dependency conflict. It doesn't seem to matter which package I try to install:

This is quite weird, because neither directory nor ghc are dependencies of rfc5051.

As a first step, can you try the following and report back whether you successfully get to a GHCi a prompt?

$ cabal repl -z --build-depends rfc5051

This results in:

desktop ~ $ cabal repl -z --build-depends rfc5051 Resolving dependencies... Build profile: -w ghc-8.8.4 -O1 In order, the following will be built (use -v for more details): - rfc5051-0.2 (lib) (requires download & build) - fake-package-0 (lib) (first run) Downloading rfc5051-0.2 Downloaded rfc5051-0.2 Starting rfc5051-0.2 (lib) Building rfc5051-0.2 (lib) Installing rfc5051-0.2 (lib) Completed rfc5051-0.2 (lib) Configuring library for fake-package-0.. Preprocessing library for fake-package-0.. Warning: No exposed modules GHCi, version 8.8.4: https://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /tmp/cabal-repl.-17863/setcwd.ghci Prelude>

Looks good, doesn't it..?

Yes, so this means that the problem is indeed the ~/.ghc/x86_64-linux-8.8.4/environments/default that Mikolaj predicted and you confirmed in a sibling thread.

For reference, here's the beginning of that file again:

clear-package-db global-package-db package-db /home/v/.cabal/store/ghc-8.8.4/package.db package-id ghc-8.8.4 package-id bytestring-0.10.10.1 package-id unix-2.7.3- f9e049162269c42fac796ce2193bc96fb95dfe3ac975de03338213cf0e37a14a package-id base-4.13.0.0 ...

What makes me wonder is, that some but not all "package-id" entries have a large hexadecimal string at the end of the line...

...

I'm not sure what the suggested fix is. I find this part of the cabal command line API extremely inscrutable.

Bye Volker _______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.

-- brandon s allbery kf8nh allbery.b@gmail.com

It looks good because you're using it the way you're supposed to instead of blindly using --lib to install things. That creates dependency issues like what you're having. Basically, don't use --lib unless you know what you're doing. Remove the environment file, and create projects with dependencies on the libraries you want, instead of trying to preinstall them. Cabal knows how to manage packages for you so they don't conflict. On Thu, Sep 15, 2022 at 12:12 PM Volker Wysk wrote:

Am Donnerstag, dem 15.09.2022 um 16:31 +0100 schrieb Tom Ellis:

...

On Thu, Sep 15, 2022 at 05:23:10PM +0200, Volker Wysk wrote:

...

I've lately set up the Haskell environment on my Linux box, with no problems. Then I have installed some packages with "cabal install", again without problems. But now I'm trying to install another package and I get a dependency conflict. It doesn't seem to matter which package I try to install:

This is quite weird, because neither directory nor ghc are dependencies of rfc5051.

As a first step, can you try the following and report back whether you successfully get to a GHCi a prompt?

$ cabal repl -z --build-depends rfc5051

This results in:

desktop ~ $ cabal repl -z --build-depends rfc5051 Resolving dependencies... Build profile: -w ghc-8.8.4 -O1 In order, the following will be built (use -v for more details): - rfc5051-0.2 (lib) (requires download & build) - fake-package-0 (lib) (first run) Downloading rfc5051-0.2 Downloaded rfc5051-0.2 Starting rfc5051-0.2 (lib) Building rfc5051-0.2 (lib) Installing rfc5051-0.2 (lib) Completed rfc5051-0.2 (lib) Configuring library for fake-package-0.. Preprocessing library for fake-package-0.. Warning: No exposed modules GHCi, version 8.8.4: https://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /tmp/cabal-repl.-17863/setcwd.ghci Prelude>

Looks good, doesn't it..?

Volker _______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.

-- brandon s allbery kf8nh allbery.b@gmail.com

The problem with the old way of doing things is exactly what you're seeing: conflicting package versions that interfere with each other. Cabal and stack both know how to expose only the package versions needed by a build, while retaining all versions needed by various build environments. On Thu, Sep 15, 2022 at 12:39 PM Volker Wysk wrote:

Am Donnerstag, dem 15.09.2022 um 12:25 -0400 schrieb Brandon Allbery:

...

It looks good because you're using it the way you're supposed to instead of blindly using --lib to install things. That creates dependency issues like what you're having. Basically, don't use --lib unless you know what you're doing.

Remove the environment file, and create projects with dependencies on the libraries you want, instead of trying to preinstall them. Cabal knows how to manage packages for you so they don't conflict.

I admit that I don't really know what I'm doing, when using cabal. I've built my projects by calling ghc from a generic Makefile for a long time now. And you're saying I should build them with "cabal build" instead? This would mean that I must change my long-fostered build environment.

Looks like I have to do some reading.

Bye, Volker

...

On Thu, Sep 15, 2022 at 12:12 PM Volker Wysk wrote:

...

Am Donnerstag, dem 15.09.2022 um 16:31 +0100 schrieb Tom Ellis:

...

On Thu, Sep 15, 2022 at 05:23:10PM +0200, Volker Wysk wrote:

...

I've lately set up the Haskell environment on my Linux box, with no problems. Then I have installed some packages with "cabal install", again without problems. But now I'm trying to install another package and I get a dependency conflict. It doesn't seem to matter which package I try to install:

This is quite weird, because neither directory nor ghc are dependencies of rfc5051.

As a first step, can you try the following and report back whether you successfully get to a GHCi a prompt?

$ cabal repl -z --build-depends rfc5051

This results in:

desktop ~ $ cabal repl -z --build-depends rfc5051 Resolving dependencies... Build profile: -w ghc-8.8.4 -O1 In order, the following will be built (use -v for more details): - rfc5051-0.2 (lib) (requires download & build) - fake-package-0 (lib) (first run) Downloading rfc5051-0.2 Downloaded rfc5051-0.2 Starting rfc5051-0.2 (lib) Building rfc5051-0.2 (lib) Installing rfc5051-0.2 (lib) Completed rfc5051-0.2 (lib) Configuring library for fake-package-0.. Preprocessing library for fake-package-0.. Warning: No exposed modules GHCi, version 8.8.4: https://www.haskell.org/ghc/ :? for help Loaded GHCi configuration from /tmp/cabal-repl.-17863/setcwd.ghci Prelude>

Looks good, doesn't it..?

Volker _______________________________________________ Haskell-Cafe mailing list To (un)subscribe, modify options or view archives go to: http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe Only members subscribed via the mailman list are allowed to post.

-- brandon s allbery kf8nh allbery.b@gmail.com