[Haskell-cafe] Problem with stack

[Bardur Arantsson]

On 25/02/2021 22.26, Olaf Klinke wrote:
> So what exactly is "locking" on the file-system level, then? I searched
> and found the term "oplocks" and that this is an option for cifs. Which
> state does stack need? oplock=on or oplock=off? My SMB server currently
> has oplock=on. Tried toggling it, still same SQLite3 locking error. 

I have no clue about stack internals, but I suspect that the only
requirements regarding file system semantics are really the requirements
of SQLite3. (Which is obviously what you're seeing.)

> It's a pity, my approach was to have as much of my Haskell stuff on a
> NAS as possible, so I wouldn't run into disk space issues. But this and
> the fact that stack/ghc stubbornly insist on using local dirs like /tmp
> make this hard. Has anynone else here successfully built a stack
> project on a cifs share? 

Judging by the output from

$ strings `which stack`|grep TMP

I'm guessing you could convince the embedded SQLite3 to use a different
temporary directory
by setting the SQLITE_TMPDIR env var.

Not sure if there are other variables of interest there. (I'm assuming
you're already setting STACK_ROOT and/or your $HOME is already on the
network drive.)

Setting TMPDIR=/foo is respected by *many* programs, not sure about
whether GHC/Cabal do.

> P.S.: Yes, I even re-mapped /tmp to another partition once to bootstrap
> ghc because it would occupy my entire tmpfs. But it would be nice if
> one could do without such tricks. 

Yeah, it's a bit of a sad state of affairs that there is only one
"TMPDIR" variable while there are typically

   /tmp -> backed by RAM
   /var/tmp -> backed by disk

on modern Linux systems.

Regards,