Allow setting custom pkgs

nix/sources.nix

@@ -125,11 +125,14 @@ let
   # The "config" used by the fetchers
   mkConfig =
     { sourcesFile ? ./sources.json
+    , sources ? builtins.fromJSON (builtins.readFile sourcesFile)
+    , pkgs ? mkPkgs sources
     }: rec {
       # The sources, i.e. the attribute set of spec name to spec
-      sources = builtins.fromJSON (builtins.readFile sourcesFile);
+      inherit sources;
+
       # The "pkgs" (evaluated nixpkgs) to use for e.g. non-builtin fetchers
-      pkgs = mkPkgs sources;
+      inherit pkgs;
     };
 in
 mkSources (mkConfig {}) // { __functor = _: settings: mkSources (mkConfig settings); }

src/Niv/Sources.hs

@@ -145,6 +145,7 @@ data SourcesNixVersion
   | V12
   | V13
   | V14
+  | V15
   deriving stock (Bounded, Enum, Eq)
 
 -- | A user friendly version
@@ -164,6 +165,7 @@ sourcesVersionToText = \case
     V12 -> "12"
     V13 -> "13"
     V14 -> "14"
+    V15 -> "15"
 
 latestVersionMD5 :: T.Text
 latestVersionMD5 = sourcesVersionToMD5 maxBound
@@ -190,6 +192,7 @@ sourcesVersionToMD5 = \case
     V12 -> "2f9629ad9a8f181ed71d2a59b454970c"
     V13 -> "5e23c56b92eaade4e664cb16dcac1e0a"
     V14 -> "b470e235e7bcbf106d243fea90b6cfc9"
+    V15 -> "dc11af910773ec9b4e505e0f49ebcfd2"
 
 -- | The MD5 sum of ./nix/sources.nix
 sourcesNixMD5 :: IO T.Text