nix-build fails with missing package.yaml

[CMCDragonkai]

these derivations will be built:
  /nix/store/kkaz3424nl8dwmchgwknwvgbpdwf1mb6-haskell-demo-source-0.1.0.0.drv
  /nix/store/qpjabqklccaxpfgs50cba5dpqb45dixj-haskell-demo-0.1.0.0.drv
building path(s) ‘/nix/store/yzya0ba2kb3c7liprwnz8hh1x5xqibxj-haskell-demo-source-0.1.0.0’
setupCompilerEnvironmentPhase
Build with /nix/store/w8ckird699qc09np3bc3h47r5g86ab8s-ghc-8.2.2.
unpacking sources
unpacking source archive /nix/store/hgha8qriz5lmcmaa20k3qy3b0d3dy8n0-Haskell-Demo
source root is Haskell-Demo
patching sources
compileBuildDriverPhase
setupCompileFlags: -package-db=/tmp/nix-build-haskell-demo-source-0.1.0.0.drv-0/package.conf.d -j8 -threaded
[1 of 1] Compiling Main             ( Setup.hs, /tmp/nix-build-haskell-demo-source-0.1.0.0.drv-0/Main.o )
Linking Setup ...
configuring
haskell-demo.cabal is up-to-date
configureFlags: --verbose --prefix=/nix/store/yzya0ba2kb3c7liprwnz8hh1x5xqibxj-haskell-demo-source-0.1.0.0 --libdir=$prefix/lib/$compiler --libsubdir=$pkgid --docdir=/share/doc --with-gcc=gcc --package-db=/tmp/nix-build-haskell-demo-source-0.1.0.0.drv-0/package.conf.d --ghc-option=-optl=-Wl,-rpath=/nix/store/yzya0ba2kb3c7liprwnz8hh1x5xqibxj-haskell-demo-source-0.1.0.0/lib/ghc-8.2.2/haskell-demo-0.1.0.0 --ghc-option=-j8 --disable-split-objs --disable-library-profiling --disable-profiling --enable-shared --disable-coverage --enable-library-vanilla --enable-executable-dynamic --enable-tests --ghc-option=-split-sections --ghc-option=-Wall --ghc-option=-Werror --extra-lib-dirs=/nix/store/54cwjh1lsmjpk2cbs43gw89w4zhk3ybb-ncurses-6.0-20171125/lib --extra-lib-dirs=/nix/store/wc2ll61lypsv9yig6mvy73c0lw1dp15a-gmp-6.1.2/lib --extra-lib-dirs=/nix/store/54cwjh1lsmjpk2cbs43gw89w4zhk3ybb-ncurses-6.0-20171125/lib
Configuring haskell-demo-0.1.0.0...
Dependency base >=4.7 && <5: using base-4.10.1.0
Dependency haskell-demo -any: using haskell-demo-0.1.0.0
Source component graph:
    component lib
    component exe:haskell-demo-exe dependency lib
    component test:haskell-demo-test dependency lib
Configured component graph:
    component haskell-demo-0.1.0.0-3DU1SIq1VjrF8GDoVDfBoM
        include base-4.10.1.0
    component haskell-demo-0.1.0.0-AyhovOrdQLIJLUjcQhWEGQ-haskell-demo-exe
        include base-4.10.1.0
        include haskell-demo-0.1.0.0-3DU1SIq1VjrF8GDoVDfBoM
    component haskell-demo-0.1.0.0-L9eSoCKaTwt86y9UN0LDt0-haskell-demo-test
        include base-4.10.1.0
        include haskell-demo-0.1.0.0-3DU1SIq1VjrF8GDoVDfBoM
Linked component graph:
    unit haskell-demo-0.1.0.0-3DU1SIq1VjrF8GDoVDfBoM
        include base-4.10.1.0
        Lib=haskell-demo-0.1.0.0-3DU1SIq1VjrF8GDoVDfBoM:Lib
    unit haskell-demo-0.1.0.0-AyhovOrdQLIJLUjcQhWEGQ-haskell-demo-exe
        include base-4.10.1.0
        include haskell-demo-0.1.0.0-3DU1SIq1VjrF8GDoVDfBoM
    unit haskell-demo-0.1.0.0-L9eSoCKaTwt86y9UN0LDt0-haskell-demo-test
        include base-4.10.1.0
        include haskell-demo-0.1.0.0-3DU1SIq1VjrF8GDoVDfBoM
Ready component graph:
    definite haskell-demo-0.1.0.0-3DU1SIq1VjrF8GDoVDfBoM
        depends base-4.10.1.0
    definite haskell-demo-0.1.0.0-AyhovOrdQLIJLUjcQhWEGQ-haskell-demo-exe
        depends base-4.10.1.0
        depends haskell-demo-0.1.0.0-3DU1SIq1VjrF8GDoVDfBoM
    definite haskell-demo-0.1.0.0-L9eSoCKaTwt86y9UN0LDt0-haskell-demo-test
        depends base-4.10.1.0
        depends haskell-demo-0.1.0.0-3DU1SIq1VjrF8GDoVDfBoM
Using Cabal-2.0.1.0 compiled by ghc-8.2
Using compiler: ghc-8.2.2
Using install prefix:
/nix/store/yzya0ba2kb3c7liprwnz8hh1x5xqibxj-haskell-demo-source-0.1.0.0
Executables installed in:
/nix/store/yzya0ba2kb3c7liprwnz8hh1x5xqibxj-haskell-demo-source-0.1.0.0/bin
Libraries installed in:
/nix/store/yzya0ba2kb3c7liprwnz8hh1x5xqibxj-haskell-demo-source-0.1.0.0/lib/ghc-8.2.2/haskell-demo-0.1.0.0
Dynamic Libraries installed in:
/nix/store/yzya0ba2kb3c7liprwnz8hh1x5xqibxj-haskell-demo-source-0.1.0.0/lib/ghc-8.2.2/x86_64-linux-ghc-8.2.2
Private executables installed in:
/nix/store/yzya0ba2kb3c7liprwnz8hh1x5xqibxj-haskell-demo-source-0.1.0.0/libexec/x86_64-linux-ghc-8.2.2/haskell-demo-0.1.0.0
Data files installed in:
/nix/store/yzya0ba2kb3c7liprwnz8hh1x5xqibxj-haskell-demo-source-0.1.0.0/share/x86_64-linux-ghc-8.2.2/haskell-demo-0.1.0.0
Documentation installed in: /share/doc
Configuration files installed in:
/nix/store/yzya0ba2kb3c7liprwnz8hh1x5xqibxj-haskell-demo-source-0.1.0.0/etc
No alex found
Using ar found on system at:
/nix/store/k8b9hqv58dd1z0j4ikak24ykndcm91s6-binutils-2.28.1/bin/ar
No c2hs found
No cpphs found
No doctest found
Using gcc version 7.3.0 given by user at:
/nix/store/9y2f87qb1djmpjs1gxl6smfkpl581waa-gcc-wrapper-7.3.0/bin/gcc
Using ghc version 8.2.2 found on system at:
/nix/store/w8ckird699qc09np3bc3h47r5g86ab8s-ghc-8.2.2/bin/ghc
Using ghc-pkg version 8.2.2 found on system at:
/nix/store/w8ckird699qc09np3bc3h47r5g86ab8s-ghc-8.2.2/bin/ghc-pkg
No ghcjs found
No ghcjs-pkg found
No greencard found
Using haddock version 2.18.1 found on system at:
/nix/store/w8ckird699qc09np3bc3h47r5g86ab8s-ghc-8.2.2/bin/haddock
No happy found
Using haskell-suite found on system at: haskell-suite-dummy-location
Using haskell-suite-pkg found on system at: haskell-suite-pkg-dummy-location
No hmake found
Using hpc version 0.67 found on system at:
/nix/store/w8ckird699qc09np3bc3h47r5g86ab8s-ghc-8.2.2/bin/hpc
Using hsc2hs version 0.68.2 found on system at:
/nix/store/w8ckird699qc09np3bc3h47r5g86ab8s-ghc-8.2.2/bin/hsc2hs
Using hscolour version 1.24 found on system at:
/nix/store/vp4d1zhp35rs0zk0pc2h1mghz2l8k7dp-hscolour-1.24.2/bin/HsColour
No jhc found
Using ld found on system at:
/nix/store/qq3xv9kwi52yvgdf13jh2swavbhw3lpd-binutils-wrapper-2.28.1/bin/ld
No lhc found
No lhc-pkg found
No pkg-config found
Using runghc version 8.2.2 found on system at:
/nix/store/w8ckird699qc09np3bc3h47r5g86ab8s-ghc-8.2.2/bin/runghc
Using strip version 2.28 found on system at:
/nix/store/k8b9hqv58dd1z0j4ikak24ykndcm91s6-binutils-2.28.1/bin/strip
Using tar found on system at:
/nix/store/7zam9d16ml78rb0p1p5gds4p5z99fpyv-gnutar-1.30/bin/tar
No uhc found
building
Distribution quality warnings:
No 'category' field.
No 'synopsis' field.
Building source dist for haskell-demo-0.1.0.0...
Preprocessing library for haskell-demo-0.1.0.0..
Preprocessing executable 'haskell-demo-exe' for haskell-demo-0.1.0.0..
Preprocessing test suite 'haskell-demo-test' for haskell-demo-0.1.0.0..
Source tarball created: dist/haskell-demo-0.1.0.0.tar.gz
running tests
haddockPhase
installing
post-installation fixup
building path(s) ‘/nix/store/c1s0gbn0gg5la0ch3q6l2lfr0rlhcidh-haskell-demo-0.1.0.0’, ‘/nix/store/xx58dm3h12c5w6cyddx9kzf5wiacl44f-haskell-demo-0.1.0.0-doc’
setupCompilerEnvironmentPhase
Build with /nix/store/w8ckird699qc09np3bc3h47r5g86ab8s-ghc-8.2.2.
unpacking sources
Source tarball is at /nix/store/yzya0ba2kb3c7liprwnz8hh1x5xqibxj-haskell-demo-source-0.1.0.0/haskell-demo-0.1.0.0.tar.gz
patching sources
compileBuildDriverPhase
setupCompileFlags: -package-db=/tmp/nix-build-haskell-demo-0.1.0.0.drv-0/package.conf.d -j8 -threaded
[1 of 1] Compiling Main             ( Setup.hs, /tmp/nix-build-haskell-demo-0.1.0.0.drv-0/Main.o )
Linking Setup ...
configuring
package.yaml: Yaml file not found: /tmp/nix-build-haskell-demo-0.1.0.0.drv-0/haskell-demo-0.1.0.0/package.yaml
builder for ‘/nix/store/qpjabqklccaxpfgs50cba5dpqb45dixj-haskell-demo-0.1.0.0.drv’ failed with exit code 1
error: build of ‘/nix/store/qpjabqklccaxpfgs50cba5dpqb45dixj-haskell-demo-0.1.0.0.drv’ failed

[CMCDragonkai]

This is now reported: NixOS/cabal2nix#373

[CMCDragonkai]

A temporary work around is to use:

hpack
cabal2nix . >./cabal.nix
cabal configure

In the shell.nix.

[CMCDragonkai]

This has been solved with adding package.yaml to the extra-source-files. Then nix-build finally works!