ghc-pkg: you don't have permissions to modify this file.

[meditans]

Hi, I'm using nix in fedora, with the nixpkgs-unstable channel.
Among the other things in my config.nix, I defined:

haskellDevEnv = self.haskellngPackages.ghcWithPackages (p: with p; [
  cabal-install
  structured-haskell-mode
]);

when I try nix-env -iA nixpkgs.haskellDevEnv i get this error towards the end of the installation:

ghc-pkg: /nix/store/s6c7wgcia36mwwq4q0k1manzi3x9ni7a-ghc-7.8.4/lib/ghc-7.8.4/package.conf.d/package.cache: you don't have permission to modify this file
builder for ‘/nix/store/xwy2dbirvjacfyb6gcbpskzyrx01mcdp-ghc-7.8.4.drv’ failed with exit code 1
error: build of ‘/nix/store/xwy2dbirvjacfyb6gcbpskzyrx01mcdp-ghc-7.8.4.drv’ failed

Any ideas on why this happens?

[peti]

This is a bug in the ghcWithLibraries function I've been meaning to fix but haven't gotten around to yet. The problem is that you have only one library in that packet list (cabal-install is a tool but no library), and the wrapper function doesn't deal gracefully with that case. It sounds silly, I know, but you can remedy that issue by (a) adding a second library to the environment, say ghc-paths, or by (b) removing cabal-install.

[meditans]

Got it, thanks for the quick reply, indeed it works with more libraries :)

2015-02-18 20:42 GMT+01:00 Peter Simons notifications@github.com:

This is a bug in the ghcWithLibraries function I've been meaning to fix
but haven't gotten around to yet. The problem is that you have only one
library in that packet list (cabal-install is a tool but no library), and
the wrapper function doesn't deal gracefully with that case. It sounds
silly, I know, but you can remedy that issue by (a) adding a second library
to the environment, say ghc-paths, or by (b) removing cabal-install.

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