stack ghci fails with permissions error for multiple users

[rosekunkel]

General summary/comments

stack ghci creates the directory /tmp/haskell-stack-ghci if it doesn't exist, which it uses to store ghci-script files that load the appropriate modules for each project. If multiple users try to use stack ghci, only the first user to do so will succeed, because /tmp/haskell-stack-ghci will be owned by them. Any other user who tries to run stack ghci will get a permissions error. This could be fixed by using a user-specific temporary directory instead (e.g. ~/.cache). The relevant code is here:

stack/src/Stack/Ghci.hs

Lines 437 to 450 in 605f74d

	tmpDirectory <-
	(</> relDirHaskellStackGhci) <$>
	(parseAbsDir =<< liftIO getCanonicalTemporaryDirectory)
	ghciDir <- view ghciDirL
	ensureDir ghciDir
	ensureDir tmpDirectory
	macrosOptions <- writeMacrosFile ghciDir pkgs
	if ghciNoLoadModules
	then execGhci macrosOptions
	else do
	checkForDuplicateModules pkgs
	isIntero <- checkIsIntero
	scriptOptions <- writeGhciScript tmpDirectory (renderScript isIntero pkgs mainFile ghciOnlyMain extraFiles)
	execGhci (macrosOptions ++ scriptOptions)

Steps to reproduce

1. Create two users, a and b, and install stack in each of their home directories.
2. Run stack ghci as user a in their home directory.
3. Exit GHCi and switch to user b.
4. Run stack ghci as user b in their home directory.

Expected

GHCi should start normally in user b's global project.

Actual

Starting GHCi fails with:

Configuring GHCi with the following packages: 
/tmp/haskell-stack-ghci/2a3bbd58: createDirectory: permission denied (Permission denied)

Stack version

$ stack --version
Version 2.1.3, Git revision 636e3a759d51127df2b62f90772def126cdf6d1f (7735 commits) x86_64 hpack-0.31.2

Method of installation

• From the Arch official repositories

[rosekunkel]

I can write a pull request to fix this, I just want to make sure that my suggested solution (using ~/.cache) is acceptable. I would probably have to add a dependency on https://hackage.haskell.org/package/xdg-basedir if that's ok.

[tmcdonell]

We have run into this as well. *sigh* A workaround is to set the environment variable TMPDIR to something unique for each user.

The getXdgDirectory function since directory-1.2.3.0 can be used without adding an extra dependency.

[AlijonovMukhammaddiyor]

Can you please give an example of how to do ?

[davidsd]

I just ran into this as well, in a case where a collaborator and I were both trying to use stack ghci on the login node of a shared cluster. It would be great to fix it.

[mauke]

Argh. I just ran into this issue at work.

It's been 3 years and it's still broken. Can't you at least include the user id in the directory name, like /tmp/haskell-stack-ghci-${UID}?

[mpilgrem]

@mauke, I will have a stab at fixing this.

[mpilgrem]

@mauke, I think the version of Stack in the rc/v2.11 release candidate branch now behaves as you wish.