Cabal: new-install fails with empty store: ghc-pkg: .../package.db: getDirectoryContents:openDirStream: does not exist (No such file or directory)

[hvr]

Invoking cabal new-install fails to initialize the respective store pkg-db if it didn't exist yet; this manifests as e.g.

$ cabal new-install -w ghc-8.6.1 hlint -vnormal+nowrap
cabal: ghc-pkg dump failed: dieVerbatim: user error (cabal: '/opt/ghc/bin/ghc-pkg-8.6.1' exited with an error:
ghc-pkg: /home/hvr/.cabal/store/ghc-8.6.0.20180810/package.db: getDirectoryContents:openDirStream: does not exist (No such file or directory)
)

cc @typedrat

---

WORKAROUND

For the respective -w argument, invoke

cabal new-repl -w ghc-8.6.1 --build-dep fail

for non-interactive environments, below seems to work:

echo "" | cabal new-repl -w ghc-8.6.1 --build-dep fail

this will build the trivial package fail and initialise the store pkg-db; after this new-install will work.

Yet another workaround suggested in https://github.com/haskell/cabal/issues/5516#issuecomment-424184066 is to create the folder package.db at the location mentioned in the error message.

[hvr]

Raising priority as this was reported to cause problems for users bootstrapping/upgrading to newer versions of cabal-install via new-install

[phadej]

This hit me in CI, where I needed to new-install some stuff into builder image. I workaround it by

    && echo 'cabal-version: 2.2'      > z.cabal \
    && echo 'name: z'                >> z.cabal \
    && echo 'version: 0'             >> z.cabal \
    && echo 'library'                >> z.cabal \
    && echo '  build-depends: aeson' >> z.cabal \
    && cat z.cabal \
    && (cabal new-build || true) \
    && rm -f z.cabal \

[hvr]

The likely place where this is caused is at

https://github.com/haskell/cabal/blob/b07e39fa414b89b18861b060b159625d40ebbf27/cabal-install/Distribution/Client/CmdInstall.hs#L445-L449

Now the question is how to tweak the code to not choke; a missing store pkg-db index folder in this codepath ought to be handled the same as if it was empty...

[LeventErkok]

Just a +1 from me on addressing this sooner. I was bit by this as I upgraded to GHC 8.6.1 and honestly there was no indication whatsoever what the resolution might be. The workaround @phadej described worked for me, though I can't claim I understand why or how.

Perhaps at least advertise how to resolve this more widely?

[psftw]

FWIW I ran in to this while updating the haskell Docker image (based on upstream ghc-8.6.1 and cabal-install-2.4 Debian packages). I've found that the directory simply needs to exist (i.e. mkdir -p $HOME/.cabal/store/ghc-8.6.1/package.db).

[hasufell]

There appears no release for this fix yet, although it is quite an important one.

[23Skidoo]

There appears no release for this fix yet, although it is quite an important one.

cabal-install-2.4.1.0 includes this fix.