Add experimental (working) implementation of git specs

nix/sources.nix

@@ -18,6 +18,9 @@ let
     else
       pkgs.fetchzip { inherit (spec) url sha256; };
 
+  fetch_git = spec:
+      builtins.fetchGit { url = spec.repo; inherit (spec) rev; };
+
   fetch_builtin-tarball = spec:
     builtins.trace
       ''
@@ -80,6 +83,7 @@ let
       abort "ERROR: niv spec ${name} does not have a 'type' attribute"
     else if spec.type == "file" then fetch_file spec
     else if spec.type == "tarball" then fetch_tarball spec
+    else if spec.type == "git" then fetch_git spec
     else if spec.type == "builtin-tarball" then fetch_builtin-tarball spec
     else if spec.type == "builtin-url" then fetch_builtin-url spec
     else

src/Niv/Git/Cmd.hs

@@ -1,4 +1,5 @@
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE TupleSections #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE Arrows #-}
 {-# LANGUAGE QuasiQuotes #-}
@@ -13,6 +14,7 @@ import Niv.Sources
 import Niv.Update
 import System.Exit (ExitCode(ExitSuccess))
 import System.Process (readProcessWithExitCode)
+import qualified Data.Aeson as Aeson
 import qualified Data.HashMap.Strict as HMS
 import qualified Data.Text as T
 import qualified Options.Applicative as Opts
@@ -29,7 +31,15 @@ gitCmd = Cmd
 
 -- TODO: don't hardcode here
 parseGitPackageSpec :: Opts.Parser PackageSpec
-parseGitPackageSpec = pure $ PackageSpec $ HMS.singleton "repo" "git@github.com:nmattia/niv"
+parseGitPackageSpec =
+    (PackageSpec . HMS.singleton "repo") <$>
+      parseRepo
+  where
+    parseRepo =
+      Aeson.String <$> Opts.strOption
+        ( Opts.long "repo" <>
+          Opts.metavar "URL"
+        )
 
 describeGit :: Opts.InfoMod a
 describeGit = mconcat

tests/git/default.nix

@@ -3,11 +3,12 @@
 # TODO: this doesn' test anything meaningful yet because "niv git PACKAGE"
 # doesn't parse yet
 pkgs.runCommand "foo"
-  { nativeBuildInputs = [ pkgs.git niv ]; }
+  { nativeBuildInputs = [ pkgs.git niv pkgs.nix pkgs.jq ]; }
+  (
+  # First we create a dummy git repo with a single commit
   ''
     gitdir=$(mktemp -d)
-
-    pushd $gitdir
+    pushd $gitdir > /dev/null
     git init .
     echo hello > file
     git config user.email "niv@foo.bar"
@@ -15,17 +16,40 @@ pkgs.runCommand "foo"
     git add file
     git commit -m "Initial commit"
     gitrev=$(git rev-parse HEAD)
-    popd
+    popd > /dev/null
+  '' +
 
+  # Then we `niv add` that repo and check some properties, like the revision
+  # and revCount, to make sure it was imported properly, and that sources.nix
+  # does what it's supposed to do.
+  ''
     nivdir=$(mktemp -d)
-    pushd $nivdir
+    pushd $nivdir > /dev/null
     mkdir -p nix
     echo "{}" > nix/sources.json
     niv init
-    # niv add git -n my-git-repo file://$gitdir
-    # nix eval --json '(import ./nix/sources.nix).my-git-repo.rev'
-    popd
+    niv add git -n my-git-repo --repo file://$gitdir
+    nivrev=$(nix eval --json '(import ./nix/sources.nix).my-git-repo.rev' | jq -r)
+    if [ ! "$gitrev" = "$nivrev" ]; then
+      echo "Mismatched revs: $gitrev != $nivrev"
+      exit 42
+    fi
+
+    # here we cheat a bit and use "outPath", which actually is the result of
+    # builtins.fetchGit.
+    nivnixrev=$(nix eval --json '(import ./nix/sources.nix).my-git-repo.outPath.rev' | jq -r)
+    if [ ! "$gitrev" = "$nivnixrev" ]; then
+      echo "Mismatched revs: $gitrev != $nivnixrev"
+      exit 42
+    fi
+    nivnixrevcount=$(nix eval --json '(import ./nix/sources.nix).my-git-repo.outPath.revCount')
+    if [ ! "1" -eq "$nivnixrevcount" ]; then
+      echo "Mismatched revCount: 1 != $nivnixrevcount"
+      exit 42
+    fi
+    popd > /dev/null
 
     touch $out
   ''
+  )