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I'm using stack ghci to start my REPL, based on the answer I got for my question on how to import a module installed with stack. This works fine, but I get initially a warning message Note: No local targets specified, so a plain ghci will be started with no package hiding or package options., followed by a bunch of suggestions about package hiding and options. My guess is that this is because I have not used stack init to setup a project, since I am still in the "playing around and learning" state and don't want a project yet. I have not found an explanation about the meaning of 'no local targets', but the effect to start a plain ghci is exactly what I want at that point. Is there a way to suppress this message? I looked at stack --help, but could not find something suitable.

user1934428
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2 Answers2

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As the Note (not warning) suggests, a plain ghci is started, which is rather uncommon situation when working with stack.

~$ stack ghci

Note: No local targets specified, so a plain ghci will be started with no package hiding or package options.

      You are using snapshot: lts-14.12

      If you want to use package hiding and options, then you can try one of the following:

      * If you want to start a different project configuration than /home/username/.stack/global-project/stack.yaml, then you can use stack init to create a new stack.yaml for the packages in the
        current directory. 

      * If you want to use the project configuration at /home/username/.stack/global-project/stack.yaml, then you can add to its 'packages' field.

Configuring GHCi with the following packages: 
GHCi, version 8.6.5: http://www.haskell.org/ghc/  :? for help
Loaded GHCi configuration from /tmp/haskell-stack-ghci/2a3bbd58/ghci-script
Prelude>

This means though that all you need to do to get the same behavior without the Note is just start ghci manually in the context of global stack environment:

~$ stack exec -- ghci
GHCi, version 8.6.5: http://www.haskell.org/ghc/  :? for help
Prelude>

In case that you want to make sure some package is installed for "playing around and learning" in the ghci session you can supply them as --package arguments

~$ stack exec --package massiv -- ghci
atomic-primops> using precompiled package
cabal-doctest > using precompiled package
scheduler     > using precompiled package
massiv        > using precompiled package
Completed 4 action(s).
GHCi, version 8.6.5: http://www.haskell.org/ghc/  :? for help
Prelude> import Data.Massiv.Array
Prelude Data.Massiv.Array>
lehins
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stack exec --ghci as in lehins's answer did not work for me, but stack exec ghci did.

Alexander Kurz
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