Merge pull request #74 from hercules-ci/release-prep

Release prep, release

CHANGELOG.md

@@ -1,6 +1,9 @@
-# Revision history for arion-compose
+# Revision history for Arion
 
-## 0.1.0.0 -- YYYY-mm-dd
+## Unreleased
 
-* First version. Released on an unsuspecting world.
-* *BREAKING:* useHostStore now uses a proper empty base image, like `scratch`.
+<!-- TODO: use better template -->
+
+## 0.1.0.0 -- 2019-10-04
+
+* First released version. Released on an unsuspecting world.

arion-compose.cabal

@@ -3,7 +3,7 @@ cabal-version:       2.4
 name:                arion-compose
 version: 0.1.0.0
 synopsis:            Run docker-compose with help from Nix/NixOS
--- description:
+description:         Arion is a tool for building and running applications that consist of multiple docker containers using NixOS modules. It has special support for docker images that are built with Nix, for a smooth development experience and improved performance.
 homepage:            https://github.com/hercules-ci/arion#readme
 -- bug-reports:
 license:             Apache-2.0
@@ -11,10 +11,10 @@ license-file:        LICENSE
 author:              Robert Hensing
 maintainer:          robert@hercules-ci.com
 -- copyright:
--- category:
-extra-source-files:  CHANGELOG.md, README.asciidoc
-write-ghc-enviroment-files:
-                     never
+category:            Distribution, Network, Cloud, Distributed Computing
+extra-source-files:  CHANGELOG.md, README.asciidoc,
+                     src/haskell/testdata/**/*.nix
+                     src/haskell/testdata/**/*.json
 data-files:          nix/*.nix
                    , nix/modules/composition/*.nix
                    , nix/modules/nixos/*.nix
@@ -24,7 +24,7 @@ data-files:          nix/*.nix
 -- all data is verbatim from some sources
 data-dir:            src
 
-common deps
+common common
   build-depends:     base ^>=4.12.0.0
                    , aeson
                    , aeson-pretty
@@ -38,25 +38,27 @@ common deps
                    , text
                    , protolude
                    , unix
+  ghc-options:     -Wall
 
 flag ghci
   default: False
   manual: True
 
 library
-  import:              deps
+  import:              common
   exposed-modules:     Arion.Nix
                        Arion.Aeson
                        Arion.DockerCompose
                        Arion.Images
                        Arion.Services
   other-modules:       Paths_arion_compose
+  autogen-modules:     Paths_arion_compose
   -- other-extensions:
   hs-source-dirs:      src/haskell/lib
   default-language:    Haskell2010
 
 executable arion
-  import:              deps
+  import:              common
   main-is:             Main.hs
   -- other-modules:
   -- other-extensions:
@@ -66,7 +68,7 @@ executable arion
   default-language:    Haskell2010
 
 test-suite arion-unit-tests
-  import:              deps
+  import:              common
   if flag(ghci)
     hs-source-dirs:      src/haskell/lib
     ghc-options:       -Wno-missing-home-modules

nix/ci.nix

@@ -1,6 +1,47 @@
-args@{ pkgs ? import ./default.nix args, system ? null, ... }:
+let
+  sources = import ./sources.nix;
+  lib = import (sources."nixpkgs" + "/lib");
+  inherit (import sources."project.nix" { inherit lib; }) dimension;
+in
 
+dimension "Nixpkgs version" {
+    "nixos-19_03" = {
+      nixpkgsSource = "nixpkgs";
+      isReferenceNixpkgs = true;
+    };
+    "nixos-19_09" = {
+      nixpkgsSource = "nixos-19.09";
+
+      # Broken since 19.09, wontfix because doc tooling will be changed.
+      # TODO: reenable
+      enableDoc = false;
+    };
+    "nixos-unstable" = {
+      nixpkgsSource = "nixos-unstable";
+
+      # Broken since 19.09, wontfix because doc tooling will be changed.
+      # TODO: reenable
+      enableDoc = false;
+    };
+  } (
+    _name: { nixpkgsSource, isReferenceNixpkgs ? false, enableDoc ? true }:
+
+
+      dimension "System" {
+        "x86_64-linux" = { isReferenceTarget = isReferenceNixpkgs; };
+        # TODO: darwin
+        # "x86_64-darwin" = { enableNixOSTests = false; };
+      } (
+        system: { isReferenceTarget ? false }:
+          let
+            pkgs = import ./. { inherit system; nixpkgsSrc = sources.${nixpkgsSource}; };
+          in
           {
             inherit (pkgs) arion tests;
+          } // lib.optionalAttrs enableDoc {
             doc = pkgs.recurseIntoAttrs (import ../doc { inherit pkgs; });
+          } // lib.optionalAttrs isReferenceTarget {
+            inherit (pkgs.arion-project.haskellPkgs) arion-compose-checked;
           }
+      )
+  )

nix/default.nix

@@ -1,12 +1,10 @@
-/**
- * This is the entry-point for all nix execution in this project.
- */
-{ nixpkgsSrc ? ./nixpkgs.nix
-, system ? null
+{ sources ? import ./sources.nix
+, nixpkgsSrc ? sources.nixpkgs
+, system ? builtins.currentSystem
 , ...
 }:
 
-import (import ./nixpkgs.nix) ({
+import nixpkgsSrc ({
   # Makes the config pure as well. See <nixpkgs>/top-level/impure.nix:
   config = {
   };
@@ -14,6 +12,5 @@ import (import ./nixpkgs.nix) ({
     # all the packages are defined there:
     (import ./overlay.nix)
   ];
-} // (if system == null then {} else {
   inherit system;
-}))
+})

nix/haskell-overlay.nix

@@ -1,4 +1,16 @@
 self: super: hself: hsuper:
 {
   arion-compose = import ./haskell-arion-compose.nix { pkgs = self; haskellPackages = hself; };
+  arion-compose-checked =
+              let pkg = super.haskell.lib.buildStrictly hself.arion-compose;
+                  checked = super.haskell.lib.overrideCabal pkg (o: {
+                    postConfigure = ''${o.postConfigure or ""}
+                      if ! ${hsuper.cabal-install}/bin/cabal check;
+                      then
+                        echo 1>&2 ERROR: cabal file is invalid. Above warnings were errors.
+                        exit 1
+                      fi
+                    '';
+                  });
+              in checked;
 }

nix/nixpkgs.nix

@@ -1,5 +0,0 @@
-# to update: $ nix-prefetch-url --unpack url
-builtins.fetchTarball {
-  url = "https://github.com/NixOS/nixpkgs/archive/bd5e8f35c2e9d1ddc9cd2fea7a23563336d54acb.tar.gz";
-  sha256 = "1wnzqqijrwf797nb234q10zb1h7086njradkkrx3a15b303grsw4";
-}

nix/overlay.nix

@@ -3,10 +3,12 @@ let
   inherit (self.arion-project) haskellPkgs;
   inherit (super) lib;
 
+  sources = import ./sources.nix;
+
 in
 {
 
-  arion = import ./arion.nix { pkgs = self; };
+  inherit (import ./.. { pkgs = self; }) arion;
   tests = super.callPackage ../tests {};
   doc = super.callPackage ../doc {};
 
@@ -19,7 +21,12 @@ in
         haskellPkgs.ghcid
         super.docker-compose
         (import ~/h/ghcide-nix {}).ghcide-ghc864
+        self.niv
+        self.releaser
       ];
     };
   };
+
+  inherit (import (sources.niv) {}) niv;
+  releaser = self.haskellPackages.callCabal2nix "releaser" sources.releaser {};
 }

nix/sources.json

@@ -0,0 +1,75 @@
+{
+    "niv": {
+        "branch": "master",
+        "description": "Easy dependency management for Nix projects",
+        "homepage": "https://github.com/nmattia/niv",
+        "owner": "nmattia",
+        "repo": "niv",
+        "rev": "1dd094156b249586b66c16200ecfd365c7428dc0",
+        "sha256": "1b2vjnn8iac5iiqszjc2v1s1ygh0yri998c0k3s4x4kn0dsqik21",
+        "type": "tarball",
+        "url": "https://github.com/nmattia/niv/archive/1dd094156b249586b66c16200ecfd365c7428dc0.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "nixos-19.09": {
+        "branch": "nixos-19.09",
+        "description": "A read-only mirror of NixOS/nixpkgs tracking the released channels. Send issues and PRs to",
+        "homepage": "https://github.com/NixOS/nixpkgs",
+        "owner": "NixOS",
+        "repo": "nixpkgs-channels",
+        "rev": "3ba0d9f75ccffd41e32cfea4046805f8bbab12f5",
+        "sha256": "0w20drs4mwlq12k1sss1x8adyf5ph5jd52n8wdcgmn4sm60qjmki",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs-channels/archive/3ba0d9f75ccffd41e32cfea4046805f8bbab12f5.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "nixos-unstable": {
+        "branch": "nixos-unstable",
+        "description": "A read-only mirror of NixOS/nixpkgs tracking the released channels. Send issues and PRs to",
+        "homepage": "https://github.com/NixOS/nixpkgs",
+        "owner": "NixOS",
+        "repo": "nixpkgs-channels",
+        "rev": "cb4332e3eb6dfdb653f1fc7397a0292df228a533",
+        "sha256": "1722wphznqhpfny08rcy19l85r2l893ckjc3h1vfivj6aj64fwjr",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs-channels/archive/cb4332e3eb6dfdb653f1fc7397a0292df228a533.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
+        "version": ""
+    },
+    "nixpkgs": {
+        "branch": "nixos-19.03",
+        "description": "A read-only mirror of NixOS/nixpkgs tracking the released channels. Send issues and PRs to",
+        "homepage": "https://github.com/NixOS/nixpkgs",
+        "owner": "NixOS",
+        "repo": "nixpkgs-channels",
+        "rev": "6420e2649fa9e267481fb78e602022dab9d1dcd1",
+        "sha256": "1z3hx7gp8nxk3fspi8vik3j9zxpajj3s7nxvjvx3b5igndxwbp74",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs-channels/archive/6420e2649fa9e267481fb78e602022dab9d1dcd1.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "project.nix": {
+        "branch": "master",
+        "description": "A configuration manager for your projects",
+        "homepage": null,
+        "owner": "hercules-ci",
+        "repo": "project.nix",
+        "rev": "33e5f3cb25feff4ccd00f8c60a05976e2ee01802",
+        "sha256": "0c3q3il5h6q3ms8m6da51knvjsfvpz12sh3a3av4d2a5ikm5ncl1",
+        "type": "tarball",
+        "url": "https://github.com/hercules-ci/project.nix/archive/33e5f3cb25feff4ccd00f8c60a05976e2ee01802.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "releaser": {
+        "branch": "master",
+        "description": "Automation of Haskell package release process.",
+        "homepage": null,
+        "owner": "domenkozar",
+        "repo": "releaser",
+        "rev": "43a4e27654f388e8eacab631e24e26792ff88fe2",
+        "sha256": "072jlbw0hdc4nvs9frd7wdyzdv4mz2dc5ib35iaqi9rzdafq6822",
+        "type": "tarball",
+        "url": "https://github.com/domenkozar/releaser/archive/43a4e27654f388e8eacab631e24e26792ff88fe2.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    }
+}

nix/sources.nix

@@ -0,0 +1,93 @@
+# This file has been generated by Niv.
+
+# A record, from name to path, of the third-party packages
+with rec
+{
+  pkgs =
+    if hasNixpkgsPath
+    then
+        if hasThisAsNixpkgsPath
+        then import (builtins_fetchTarball { inherit (sources_nixpkgs) url sha256; }) {}
+        else import <nixpkgs> {}
+    else
+        import (builtins_fetchTarball { inherit (sources_nixpkgs) url sha256; }) {};
+
+  sources_nixpkgs =
+    if builtins.hasAttr "nixpkgs" sources
+    then sources.nixpkgs
+    else abort
+    ''
+        Please specify either <nixpkgs> (through -I or NIX_PATH=nixpkgs=...) or
+        add a package called "nixpkgs" to your sources.json.
+    '';
+
+  # fetchTarball version that is compatible between all the versions of Nix
+  builtins_fetchTarball =
+      { url, sha256 }@attrs:
+      let
+        inherit (builtins) lessThan nixVersion fetchTarball;
+      in
+        if lessThan nixVersion "1.12" then
+          fetchTarball { inherit url; }
+        else
+          fetchTarball attrs;
+
+  # fetchurl version that is compatible between all the versions of Nix
+  builtins_fetchurl =
+      { url, sha256 }@attrs:
+      let
+        inherit (builtins) lessThan nixVersion fetchurl;
+      in
+        if lessThan nixVersion "1.12" then
+          fetchurl { inherit url; }
+        else
+          fetchurl attrs;
+
+  # A wrapper around pkgs.fetchzip that has inspectable arguments,
+  # annoyingly this means we have to specify them
+  fetchzip = { url, sha256 }@attrs: pkgs.fetchzip attrs;
+
+  # A wrapper around pkgs.fetchurl that has inspectable arguments,
+  # annoyingly this means we have to specify them
+  fetchurl = { url, sha256 }@attrs: pkgs.fetchurl attrs;
+
+  hasNixpkgsPath = (builtins.tryEval <nixpkgs>).success;
+  hasThisAsNixpkgsPath =
+    (builtins.tryEval <nixpkgs>).success && <nixpkgs> == ./.;
+
+  sources = builtins.fromJSON (builtins.readFile ./sources.json);
+
+  mapAttrs = builtins.mapAttrs or
+    (f: set: with builtins;
+      listToAttrs (map (attr: { name = attr; value = f attr set.${attr}; }) (attrNames set)));
+
+  # borrowed from nixpkgs
+  functionArgs = f: f.__functionArgs or (builtins.functionArgs f);
+  callFunctionWith = autoArgs: f: args:
+    let auto = builtins.intersectAttrs (functionArgs f) autoArgs;
+    in f (auto // args);
+
+  getFetcher = spec:
+    let fetcherName =
+      if builtins.hasAttr "type" spec
+      then builtins.getAttr "type" spec
+      else "builtin-tarball";
+    in builtins.getAttr fetcherName {
+      "tarball" = fetchzip;
+      "builtin-tarball" = builtins_fetchTarball;
+      "file" = fetchurl;
+      "builtin-url" = builtins_fetchurl;
+    };
+};
+# NOTE: spec must _not_ have an "outPath" attribute
+mapAttrs (_: spec:
+  if builtins.hasAttr "outPath" spec
+  then abort
+    "The values in sources.json should not have an 'outPath' attribute"
+  else
+    if builtins.hasAttr "url" spec && builtins.hasAttr "sha256" spec
+    then
+      spec //
+      { outPath = callFunctionWith spec (getFetcher spec) { }; }
+    else spec
+  ) sources

src/haskell/exe/Main.hs

@@ -12,20 +12,13 @@ import qualified Arion.DockerCompose as DockerCompose
 import           Arion.Services (getDefaultExec)
 
 import Options.Applicative
-import Control.Applicative
 import Control.Monad.Fail
 
-import qualified Data.Aeson.Encode.Pretty
 import qualified Data.Text as T
 import qualified Data.Text.IO as T
-import qualified Data.Text.Lazy as TL
-import qualified Data.Text.Lazy.Builder as TB
 
-import qualified Data.List.NonEmpty as NE
 import Data.List.NonEmpty (NonEmpty(..))
 
-import Control.Arrow ((>>>))
-
 import System.Posix.User (getRealUserID)
 
 data CommonOptions =
@@ -69,6 +62,7 @@ parseOptions = do
       let nixArgs = userNixArgs <|> "--show-trace" <$ guard showTrace
       in CommonOptions{..}
 
+textArgument :: Mod ArgumentFields [Char] -> Parser Text
 textArgument = fmap T.pack . strArgument
 
 parseCommand :: Parser (CommonOptions -> IO ())
@@ -124,18 +118,18 @@ commandDC
   -> Text
   -> Text
   -> Mod CommandFields (CommonOptions -> IO ())
-commandDC run cmdStr help =
+commandDC run cmdStr helpText =
   command
     (T.unpack cmdStr)
     (info
       (run cmdStr <$> parseDockerComposeArgs)
-      (progDesc (T.unpack help) <> fullDesc <> forwardOptions))
+      (progDesc (T.unpack helpText) <> fullDesc <> forwardOptions))
 
 
 --------------------------------------------------------------------------------
 
 runDC :: Text -> DockerComposeArgs -> CommonOptions -> IO ()
-runDC cmd (DockerComposeArgs args) opts = do
+runDC cmd (DockerComposeArgs args) _opts = do
   DockerCompose.run DockerCompose.Args
     { files = []
     , otherArgs = [cmd] ++ args
@@ -265,7 +259,7 @@ runExec detach privileged user noTTY index envs workDir service commandAndArgs o
 
 main :: IO ()
 main = 
-  (join . execParser) (info (parseAll <**> helper) fullDesc)
+  (join . arionExecParser) (info (parseAll <**> helper) fullDesc)
   where
-    execParser = customExecParser (prefs showHelpOnEmpty)
+    arionExecParser = customExecParser (prefs showHelpOnEmpty)
 

src/haskell/lib/Arion/Aeson.hs

@@ -4,11 +4,9 @@ import Prelude ()
 import           Data.Aeson
 import qualified Data.ByteString.Lazy          as BL
 import qualified Data.Text.Lazy                as TL
-import qualified Data.Text.Lazy.IO             as TL
 import qualified Data.Text.Lazy.Builder        as TB
 import qualified Data.Aeson.Encode.Pretty
 import           Data.Aeson.Encode.Pretty       ( defConfig
-                                                , keyOrder
                                                 , confCompare
                                                 , confTrailingNewline
                                                 )

src/haskell/lib/Arion/DockerCompose.hs

@@ -3,24 +3,7 @@ module Arion.DockerCompose where
 
 import           Prelude                        ( )
 import           Protolude
-import           Arion.Aeson                    ( pretty )
-import           Data.Aeson
-import qualified Data.String
 import           System.Process
-import qualified Data.ByteString               as BS
-import qualified Data.ByteString.Lazy          as BL
-import           Paths_arion_compose
-import           Control.Applicative
-
-import qualified Data.Text                     as T
-import qualified Data.Text.IO                  as T
-
-import qualified Data.List.NonEmpty            as NE
-import           Data.List.NonEmpty             ( NonEmpty(..) )
-
-import           Control.Arrow                  ( (>>>) )
-import           System.IO.Temp                 ( withTempFile )
-import           System.IO                      ( hClose )
 
 data Args = Args
   { files :: [FilePath]
@@ -43,6 +26,5 @@ run args = do
     case exitCode of
       ExitSuccess -> pass
       ExitFailure 1 -> exitFailure
-      e@ExitFailure {} -> do
+      ExitFailure {} -> do
         throwIO $ FatalError $ "docker-compose failed with " <> show exitCode
-        exitWith e

src/haskell/lib/Arion/Images.hs

@@ -10,7 +10,6 @@ import Protolude hiding (to)
 
 import qualified Data.Aeson as Aeson
 import           Arion.Aeson (decodeFile)
-import qualified Data.ByteString as BS
 import qualified System.Process as Process
 
 import Control.Lens

src/haskell/lib/Arion/Nix.hs

@@ -16,12 +16,9 @@ import           Data.Aeson
 import qualified Data.String
 import qualified System.Directory              as Directory
 import           System.Process
-import qualified Data.ByteString               as BS
 import qualified Data.ByteString.Lazy          as BL
 import           Paths_arion_compose
-import           Control.Applicative
 
-import qualified Data.Text                     as T
 import qualified Data.Text.IO                  as T
 
 import qualified Data.List.NonEmpty            as NE
@@ -76,21 +73,20 @@ evaluateComposition ea = do
     case exitCode of
       ExitSuccess -> pass
       ExitFailure 1 -> exitFailure
-      e@ExitFailure {} -> do
+      ExitFailure {} -> do
         throwIO $ FatalError $ "evaluation failed with " <> show exitCode
-        exitWith e
 
     case v of
       Right r -> pure r
-      Left  e -> throwIO $ FatalError "Couldn't parse nix-instantiate output"
+      Left  e -> throwIO $ FatalError ("Couldn't parse nix-instantiate output" <> show e)
 
 -- | Run with docker-compose.yaml tmpfile
 withEvaluatedComposition :: EvaluationArgs -> (FilePath -> IO r) -> IO r
 withEvaluatedComposition ea f = do
   v <- evaluateComposition ea
-  withTempFile "." ".tmp-arion-docker-compose.yaml" $ \path handle -> do
-    T.hPutStrLn handle (pretty v)
-    hClose handle
+  withTempFile "." ".tmp-arion-docker-compose.yaml" $ \path yamlHandle -> do
+    T.hPutStrLn yamlHandle (pretty v)
+    hClose yamlHandle
     f path
 
 
@@ -117,15 +113,14 @@ buildComposition outLink ea = do
     case exitCode of
       ExitSuccess -> pass
       ExitFailure 1 -> exitFailure
-      e@ExitFailure {} -> do
+      ExitFailure {} -> do
         throwIO $ FatalError $ "nix-build failed with " <> show exitCode
-        exitWith e
 
 -- | Do something with a docker-compose.yaml.
 withBuiltComposition :: EvaluationArgs -> (FilePath -> IO r) -> IO r
 withBuiltComposition ea f = do
-  withTempFile "." ".tmp-arion-docker-compose.yaml" $ \path handle -> do
-    hClose handle
+  withTempFile "." ".tmp-arion-docker-compose.yaml" $ \path emptyYamlHandle -> do
+    hClose emptyYamlHandle
     -- Known problem: kills atomicity of withTempFile; won't fix because we should manage gc roots,
     -- impl of which will probably avoid this "problem". It seems unlikely to cause issues.
     Directory.removeFile path
@@ -149,9 +144,8 @@ replForComposition ea = do
       case exitCode of
         ExitSuccess -> pass
         ExitFailure 1 -> exitFailure
-        e@ExitFailure {} -> do
+        ExitFailure {} -> do
           throwIO $ FatalError $ "nix repl failed with " <> show exitCode
-          exitWith e
 
 argArgs :: EvaluationArgs -> [[Char]]
 argArgs ea =

src/haskell/lib/Arion/Services.hs

@@ -10,13 +10,9 @@ import Protolude hiding (to)
 
 import qualified Data.Aeson as Aeson
 import           Arion.Aeson (decodeFile)
-import qualified Data.ByteString as BS
-import qualified System.Process as Process
 
 import Control.Lens
 import Data.Aeson.Lens
-import Data.String
-import System.IO (withFile, IOMode(ReadMode))
 
 -- | Subject to change
 getDefaultExec :: FilePath -> Text -> IO [Text]

src/haskell/test/Arion/NixSpec.hs

@@ -6,16 +6,11 @@ where
 
 import           Protolude
 import           Test.Hspec
-import           Test.QuickCheck
 import qualified Data.List.NonEmpty            as NEL
 import           Arion.Aeson
 import           Arion.Nix
 import qualified Data.Text                     as T
 import qualified Data.Text.IO                  as T
-import qualified Data.Text.Lazy.IO             as TL
-import qualified Data.Text.Lazy.Builder        as TB
-import qualified Data.Aeson.Encode.Pretty
-import Data.Char (isSpace)
 
 spec :: Spec
 spec = describe "evaluateComposition" $ it "matches an example" $ do
@@ -32,8 +27,8 @@ spec = describe "evaluateComposition" $ it "matches an example" $ do
   expected <- T.readFile "src/haskell/testdata/Arion/NixSpec/arion-compose.json"
   censorPaths actual `shouldBe` censorPaths expected
 
+censorPaths :: Text -> Text
 censorPaths = censorImages . censorStorePaths
---censorPaths = censorStorePaths
 
 censorStorePaths :: Text -> Text
 censorStorePaths x = case T.breakOn "/nix/store/" x of
@@ -61,4 +56,4 @@ isNixNameChar c | c >= 'A' && c <= 'Z' = True
 isNixNameChar c | c == '-' = True
 isNixNameChar c | c == '.' = True
 isNixNameChar c | c == '_' = True -- WRONG?
-isNixNameChar c = False -- WRONG?
+isNixNameChar _ = False -- WRONG?

src/haskell/test/TestMain.hs

@@ -1,5 +1,6 @@
 module Main where
 
+import           Prelude()
 import           Protolude
 import           Test.Hspec.Runner
 import qualified Spec