"Materialized nix used for dummy-data-ghc-8.6.4 is missing"

[michaelpj]

This occurs when trying to build a stack project whose resolver pins it to 8.6.4 (concretely, https://gitlab.com/joneshf/purty at 3c073e1149ecdddd01f1d371c70d5b243d743bf2).

The error is actually from trying to get the nix-tools plan, which as of #738 we build with the same GHC as the project. I'm not sure whether it would in fact fail on the plan for the main project too if it kept going.

[michaelpj]

Not sure, but I think this might mean that any project using 8.6.4 (or other versions where we don't have the materialized files) is broken.

[michaelpj]

(I also enjoyed building cabal 3 times for the various different versions of nix-tools used by various tools we build. Still think we should just do this once.)

[michaelpj]

Although actually this seems wrong: we explicitly use the internal nix tools for stack projects. So I have no idea what's going on after all.

[hamishmack]

The materialization files are #812, but I think a better fix is to use ghc 8.6.5 by adding this and this.

[michaelpj]

Here's some more error:

builder for '/nix/store/n83jsqp0l1yr2dy9l3gd4n1ydvyxz5yw-dummy-data-ghc-8.6.4.drv' failed with exit code 1                                                                                                                                                                                                                  
building '/nix/store/cgvczl1sckjbcmhjrldljbx5mw427ra3-cborg-lib-cborg-0.2.3.0.drv'...                                                                                                                                                                                                                                       
cannot build derivation '/nix/store/ch7jab0qk2mh75k5gfs4d2dnxds9n2xh-dummy-ghc-8.6.4.drv': 1 dependencies couldn't be built                                                                                                                                                                                                 
cannot build derivation '/nix/store/l49ljj2j8nbncqn442dmmxkvy77hj4vm-dummy-pkg-ghc-8.6.4.drv': 1 dependencies couldn't be built                                                                                                                                                                                             
building '/nix/store/6mjm8a954aiccgk4wq29p3m9vswyis68-exceptions-lib-exceptions-0.10.4-config.drv'...                                                                                                                                                                                                                       
building '/nix/store/4ry6ybq0z155iq6x1frrn2zz6y7jm93q-haskell-src-exts-lib-haskell-src-exts-1.23.0.drv'...                                                                                                                                                                                                                  
building '/nix/store/cayihmzqwywhvqfcm0amxyc36b2hl7hd-megaparsec-lib-megaparsec-8.0.0-config.drv'...                                                                                                                                                                                                                        
building '/nix/store/1vsc3ck2c3b7wp4b72f460cmkcawidbg-ref-tf-lib-ref-tf-0.4.0.2-config.drv'...                                                                                                                                                                                                                              
building '/nix/store/1x9x1cmam5qm8jrwk4z7c3vjx2kl26l4-socks-lib-socks-0.6.1.drv'...                                                                                                                                                                                                                                         
building '/nix/store/iiq3jcx49fh2bh5rwliyg4rmgclr1yg8-terminfo-lib-terminfo-0.4.1.2.drv'...                                                                                                                                                                                                                                 
building '/nix/store/rjh7vvfv7lm3bf52nsh3g89ghfzr9gv6-th-expand-syns-lib-th-expand-syns-0.4.6.0-config.drv'...                                                                                                                                                                                                              
cannot build derivation '/nix/store/b9hsip7f3bwqgx8s6fwjnaz62ddyravk-nix-tools-plan-to-nix-pkgs.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/7733qz1dzrss90p4snwr6bij6y2x68yd-generateMaterialized.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/wcm2jndr0cdi6bg9x7jp4qgi7w8hs6qm-updateMaterialized.drv': 1 dependencies couldn't be built
cannot build derivation '/nix/store/vrp9y555zy0hh6a6pksrf4nc2m37fasz-nix-tools-plan-to-nix-pkgs.drv': 1 dependencies couldn't be built
error: while evaluating the attribute 'buildInputs' of the derivation 'purty-exe-purty-4.5.1' at /nix/store/x0vxvwcf9hja4m9x73ajrz3210r04f8y-source/pkgs/stdenv/generic/make-derivation.nix:191:11:

[michaelpj]

Thanks, that should help with the specific issue, although I do think that this should work. Are we going to commit to having the materialized files for all the GHC versions we have?

[hamishmack]

#816 should have fix this particular issue for all stackProjects like purty.

I think #817 might be the way to go for cabalProject. It does run the risk of building ghc during IFD, but only if the user explicitly asks for a ghc that does not have materialized dummy-ghc-data.

[michaelpj]

We made this quite a lot better.