Add to FAQ how to trick stack to install a GHC binary archive on Windows

[louy2]

Due to connection issues it is extremely slow to stack setup here. I tried to set http_proxy but got a segfault instead.

Is there a place I can download the exact same thing as stack setup and put it manually into where it is supposed to be?

[louy2]

So I've got this: https://www.haskell.org/ghc/download_ghc_7_10_3#windows64
And I found in FAQ:

Note that stack setup installs GHC into ~/.stack/programs/$platform/ghc-$version/ and not a global location.

But it is not clear what are the $platform's. On the other hand, it is also stated

stack is fully aware of all GHCs that it has installed itself.

So I am unsure if putting file there can trick stack into thinking it has installed that one.

[louy2]

Success! Hail the power of Everything.

By searching ghc in Everything I found that the temporary folder holding the download progress is %APPDATA%/Local/Programs/stack/x86_64-windows. I downloaded http://downloads.haskell.org/~ghc/7.10.3/ghc-7.10.3b-x86_64-unknown-mingw32.tar.xz and renamed it to ghc-7.10.3.tar.xz, and put it in there. A subsequent stack setup regards it as downloaded GHC and installed it normally.

Maybe this is worth mentioning in FAQ?

[louy2]

I am so confused. I have full control of the home dir for sure, but I get Access Denied at the end.

Full error:

C:\Users\yang\AppData\Local\Programs\stack\x86_64-windows\ghc-7.10.3-tmp4660\ghc-7.10.3\: MoveFileEx "C:\\Users\\yang\\AppData\\Local\\Programs\\stack\\x86_64-windows\\ghc-7.10.3-tmp4660\\ghc-7.10.3\\" "C:\\Users\\yang\\AppData\\Local\\Programs\\stack\\x86_64-windows\\ghc-7.10.3\\": permission denied (Access is denied.)

[mgsloan]

Not exactly a frequent question, so I'm not sure if it belongs in the FAQ. It might be worth having something document the folder structure, though, including the programs folder. Just having this issue is good for letting people know how to do it in the future.

Note that this isn't very windows specific. The tarballs just go in stack path --ghc-paths.

RE the Acess Denied, seems like the same issue as #1917

[reverofevil]

Great advice. Until #2240 gets fixed, this should be in the manual.

[mgsloan]

Sure, by popular demand I'd accept a PR adding a note about this to the manual.

[KiaraGrouwstra]

~/.stack/programs/x86_64-linux/ keeps putting a ghc-8.0.2.tar.xz.tmp that takes ages, so now I've put a manually downloaded/renamed ghc-8.0.2.tar.xz in there, alongside a manually extracted ghc-8.0.2 folder.
stack setup appears to keep starting a new download though, apparently contradicting @louy2's account. I wonder if I might've done anything wrong... Stack version 0.1.10.0 x86_64.

[mgsloan]

@tycho01 The issue is that is an ancient version of stack.

[KiaraGrouwstra]

@msgloan: thanks! 😄

[dtaskoff]

Is there a place I can download the exact same thing as stack setup and put it manually into where it is supposed to be?

I think that this is a bad idea.

Due to connection issues it is extremely slow to stack setup here.

Then download the ghc locally and set it in your stack.yaml like that:

setup-info:
  ghc:
    linux64-integersimple:
      8.0.2:
        url: /home/me/ghc/ghc-8.0.2-x86_64-unknown-linux.tar.xz

Of course, you should modify the above to fit your case, but note that the url field should be an absolute path.

[rgrinberg]

@tycho01's work around doesn't work for me. stack keeps trying to redownload things.

Here's my ghc dir:

[rgrinberg:~/.stack/programs/x86_64-osx] % ls
ghc-8.0.2               ghc-8.0.2.installed     ghc-8.0.2.tar.bz2       ghc-8.2.2               ghc-8.2.2.tar.bz2       ghc-8.2.2.tar.bz2.tmp