Why does “cabal sdist” not include all “files needed to build”?

Question

According to the wiki entry,

It packages up the files needed to build the project

I have a simple executables-only .cabal project, which basically contains

Executable myprog
  hs-source-dirs: src
  main-is: MyMain.hs

and is made up of some additional .hs files below src/ beyond src/MyMain.hs. E.g., src/Utils.hs and a few others.

cabal build has no problems building myprog, and compiles the required additional .hs files below src/, but cabal sdist does not, thus creating a dysfunctional source-tarball. What am I doing wrong? How do I tell cabal to include all source files below hs-source-dirs?

As a side-note, with GNU Autotools, there was a make distcheck target, which would first build a source-tarball, and then try to build the project via the newly generated source-tarball, thus ensuring everything's ok. Is there something similar for cabal, in order to make sure my source-tarball is sound?

Answer 1

You should list the other Haskell files in the .cabal file, inside the Executable stanza.

  other-modules: Utils AFewOthers

The distribution only includes source files that are listed in your .cabal file. Cabal has no other way to detect which source files are in your package. You could still build because cabal build calls ghc --make, and ghc will find and compile all the source files it needs.