custom-setup's Setup.hs fails to build with --disable-library-vanilla

[RyanGlScott]

(Originally reported at ulidtko/cabal-doctest#24.)

To reproduce the issue, attempt to build any library with a custom-setup (that depends on another library) using --disable-library-vanilla. distributive-0.5.3 is a handy test case here, since it depends on cabal-doctest-1.0.2:

$ cabal get distributive-0.5.3
$ cd distributive-0.5.3/                              
$ cabal sandbox init                     
$ cabal install --disable-library-vanilla distributive-0.5.3
Resolving dependencies...
Notice: installing into a sandbox located at
/home/rgscott/Documents/Hacking/Haskell/distributive-0.5.3/.cabal-sandbox
Configuring cabal-doctest-1.0.2...
Configuring base-orphans-0.6...
Configuring transformers-compat-0.5.1.4...
Building cabal-doctest-1.0.2...
Building base-orphans-0.6...
Building transformers-compat-0.5.1.4...
Installed base-orphans-0.6
Installed transformers-compat-0.5.1.4
Configuring tagged-0.8.5...
Installed cabal-doctest-1.0.2
Building tagged-0.8.5...
Installed tagged-0.8.5
Configuring distributive-0.5.3...
Failed to install distributive-0.5.3
Build log ( /home/rgscott/Documents/Hacking/Haskell/distributive-0.5.3/.cabal-sandbox/logs/ghc-8.2.1/distributive-0.5.3-JhCddFf7ooB4a6MBkynMRP.log ):
cabal: Entering directory '/tmp/cabal-tmp-29865/distributive-0.5.3'
cabal: Leaving directory '/tmp/cabal-tmp-29865/distributive-0.5.3'
cabal: Error: some packages failed to install:
distributive-0.5.3-JhCddFf7ooB4a6MBkynMRP failed during the configure step.
The exception was:
dieVerbatim: user error (cabal: '/opt/ghc/8.2.1/bin/ghc' exited with an error:

/tmp/cabal-tmp-29865/distributive-0.5.3/dist/dist-sandbox-b0108747/setup/setup.hs:12:1:
error:
Could not find module ‘Distribution.Extra.Doctest’
There are files missing in the ‘cabal-doctest-1.0.2’ package,
try running 'ghc-pkg check'.
Use -v to see a list of the files searched for.
|
12 | import Distribution.Extra.Doctest ( defaultMainWithDoctests )
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)

(In case you're curious why I'm trying to install something with --disable-library-vanilla: apparently it's a default option on Manjaro/Arch Linux.)

[23Skidoo]

Is this the same as #1720?

[RyanGlScott]

I believe it is. Thanks for pointing that out.