Flakify all inputs (input-output-hk#1180)

* Include dependencies of haskell.nix that were tracked in `nix/sources.json`
  as flake inputs (`flake.lock` replaces `nix/sources.json`).
* Use `flake-compat` to continue to provide a compatible interface for non
  flake projects.

Co-authored-by: Alexander Bantyev <[email protected]>
Co-authored-by: Shea Levy <[email protected]>

build.nix

@@ -35,15 +35,15 @@ in rec {
   maintainer-scripts = pkgs.dontRecurseIntoAttrs {
     update-hackage = import ./scripts/update-hackage.nix {
       inherit (pkgs) stdenv lib writeScript coreutils glibc git
-        openssh nix-prefetch-git gawk bash curl findutils;
+        openssh nixFlakes gawk bash curl findutils;
       # Update scripts use the internal nix-tools and cabal-install (compiled with a fixed GHC version)
       nix-tools = haskell.internal-nix-tools;
       cabal-install = haskell.internal-cabal-install;
       inherit (haskell) update-index-state-hashes;
     };
     update-stackage = haskell.callPackage ./scripts/update-stackage.nix {
       inherit (pkgs) stdenv lib writeScript coreutils glibc git
-        openssh nix-prefetch-git gawk bash curl findutils;
+        openssh nixFlakes gawk bash curl findutils;
       # Update scripts use the internal nix-tools and cabal-install (compiled with a fixed GHC version)
       nix-tools = haskell.internal-nix-tools;
       cabal-install = haskell.internal-cabal-install;

changelog.md

@@ -1,6 +1,12 @@
 This file contains a summary of changes to Haskell.nix and `nix-tools`
 that will impact users.
 
+## Aug 6, 2021
+* Included dependencies of haskell.nix that were tracked in `nix/sources.json`
+  as flake inputs (`flake.lock` replaces `nix/sources.json`).
+* Uses `flake-compat` to continue to provide a compatible interface for non
+  flake projects.
+
 ## Jul 23, 2021
 * `source-repository-package` references in `cabal.project` files are now
   left as a `source-repository-package` when calculating the the `plan-nix` for

ci-lib.nix

@@ -1,8 +1,8 @@
-let
+{
   # Generic nixpkgs, use *only* for lib functions that are stable across versions
-  pkgs = import (import ./nix/sources.nix).nixpkgs {};
-  lib = pkgs.lib;
-in rec {
+  pkgs ? (import ./. {}).pkgs,
+  lib ? pkgs.lib
+}: rec {
   inherit (import ./dimension.nix) dimension;
 
   # A filter for removing packages that aren't supported on the current platform

ci.nix

@@ -4,10 +4,11 @@
 , ifdLevel ? 3
 # Whether or not we are evaluating in restricted mode. This is true in Hydra, but not in Hercules.
 , restrictEval ? false
-, checkMaterialization ? false }:
+, checkMaterialization ? false
+, pkgs ? (import ./. {}).pkgs }:
  let
-  inherit (import ./ci-lib.nix) dimension platformFilterGeneric filterAttrsOnlyRecursive;
-  sources = import ./nix/sources.nix {};
+  inherit (import ./ci-lib.nix { inherit pkgs; }) dimension platformFilterGeneric filterAttrsOnlyRecursive;
+  inherit (pkgs.haskell-nix) sources;
   nixpkgsVersions = {
     "R2009" = "nixpkgs-2009";
     "R2105" = "nixpkgs-2105";

default.nix

@@ -1,23 +1,17 @@
-{ checkMaterialization ? false  # Allows us to easily switch on materialization checking
-, system ? builtins.currentSystem
-, sourcesOverride ? {}
-, ... }@args: rec {
-  sources  = (import ./nix/sources.nix { inherit pkgs; }) // sourcesOverride;
-  config   = import ./config.nix;
-  overlays = [ allOverlays.combined ] ++ (
-    if checkMaterialization == true
-      then [(
-        final: prev: {
-          haskell-nix = prev.haskell-nix // {
-            checkMaterialization = true;
-          };
-        }
-      )]
-      else []
-  );
-  allOverlays = import ./overlays args;
-  nixpkgsArgs = { inherit config overlays system; };
-  pkgs = import sources.nixpkgs nixpkgsArgs;
-  pkgs-unstable = import sources.nixpkgs-unstable nixpkgsArgs;
-  hix = import ./hix/default.nix;
-}
+{...}@args:
+
+let
+  nixpkgsSrc = 
+    builtins.fetchTarball {
+      url = "https://github.com/NixOS/nixpkgs/archive/3c6f3f84af60a8ed5b8a79cf3026b7630fcdefb8.tar.gz";
+      sha256 = "sha256:0jf9l6j60sa8cms7r4a02kr9j9884pwv1prf79b2ysnxmnhimnch";
+    };
+  pkgs = args.pkgs or import nixpkgsSrc {};
+  flake-compat =
+    pkgs.fetchzip {
+      url = "https://github.com/hamishmack/flake-compat/archive/ce16b21b8a5588aa8b532353d3ceea89a38b8e77.tar.gz";
+      sha256 = "sha256:054nsfqh3wy6v6bjamw0k91xl8v1rc5x2laic8mphrkrhzvyz5hi";
+    };
+  self = import flake-compat { src = ./.; inherit pkgs; };
+in self.defaultNix.internal.compat
+({ system = args.pkgs.system or builtins.currentSystem; } // args) // self.defaultNix