How to build Haskell app with a dependencies?

Question

I have the Haskell application with some dependencies. A one package from the dependencies contains a bugfix, which wasn't included into the hackage release yet, so I want to install it from github directly.

git clone http://github.com/some/repo .deps/repo
cabal sandbox init
cabal sandbox add-source .deps/repo/
cabal install --only-dependencies
cabal build

But instead of the successful building I have an error

Could not find module `Some.Repo.Module'

.cabal-sandbox directory contains the file add-source-timestamps

[("x86_64-linux-ghc-7.6.3",[("/home/user/app/.deps/repo",0)])]

but nothing else.

What I'm doing wrong? Maybe I'm missed some steps?

Answer 1

If you want to import the packages in the sandbox sources, you still need to add them as build dependencies to your cabal file.

This answer is derived from the comments to the question.