Upgrade nixpkgs to current master and add an upgrade checklist (#1579)

* simplify haskell packages overrides based on new nixpkgs
* update Nix gitignore
* simplify Haskell packages overlay

Co-authored-by: monacoremo <monacoremo>

nix/overlays/default.nix

@@ -1,7 +1,7 @@
 {
   gitignore = import ./gitignore.nix;
   ghr = import ./ghr;
-  haskell-packages = import ./haskell-packages;
+  haskell-packages = import ./haskell-packages.nix;
   postgresql-default = import ./postgresql-default.nix;
   postgresql-legacy = import ./postgresql-legacy.nix;
 }

nix/overlays/ghr/ghr.nix

@@ -12,4 +12,7 @@ buildGoModule rec {
   };
 
   vendorSha256 = "14avsngzhl1b8a05i43ph6sxh9vj0jls0acxr9j7r0h3f0vpamcj";
+
+  # Disabling tests, as they require a GitHub API token
+  doCheck = false;
 }

nix/overlays/gitignore.nix

@@ -12,8 +12,8 @@ self: super:
       gitignoreSrc = super.fetchFromGitHub {
         owner = "hercules-ci";
         repo = "gitignore";
-        rev = "2ced4519f865341adcb143c5d668f955a2cb997f";
-        sha256 = "sha256:0fc5bgv9syfcblp23y05kkfnpgh3gssz6vn24frs8dzw39algk2z";
+        rev = "c4662e662462e7bf3c2a968483478a665d00e717";
+        sha256 = "1npnx0h6bd0d7ql93ka7azhj40zgjp815fw2r6smg8ch9p7mzdlx";
       };
     in
     (super.callPackage gitignoreSrc { }).gitignoreSource;

nix/overlays/haskell-packages.nix

@@ -0,0 +1,31 @@
+{ compiler, extraOverrides ? (final: prev: { }) }:
+
+self: super:
+let
+  overrides =
+    final: prev:
+    rec {
+      # To pin custom versions of Haskell packages:
+      #   protolude =
+      #     prev.callHackageDirect
+      #       {
+      #         pkg = "protolude";
+      #         ver = "0.3.0";
+      #         sha256 = "0iwh4wsjhb7pms88lw1afhdal9f86nrrkkvv65f9wxbd1b159n72";
+      #       }
+      #       { };
+      #
+      # To get the sha256:
+      #   nix-prefetch-url --unpack https://hackage.haskell.org/package/protolude-0.3.0/protolude-0.3.0.tar.gz
+      protolude = prev.protolude_0_3_0;
+    } // extraOverrides final prev;
+in
+{
+  haskell =
+    super.haskell // {
+      packages = super.haskell.packages // {
+        "${compiler}" =
+          super.haskell.packages."${compiler}".override { inherit overrides; };
+      };
+    };
+}

nix/overlays/haskell-packages/README.md

@@ -1,10 +0,0 @@
-The `.nix` files in this directory pin specific versions of Haskell packages
-from Hackage. They were generated with `cabal2nix`, e.g.:
-
-```bash
-cabal2nix cabal://Cabal-3.0.0.0 > Cabal.nix
-
-```
-
-Those overrides will likely become obsolete as the pinned versions are adopted
-into our pinned version of nixpkgs.

nix/overlays/haskell-packages/default.nix

@@ -1,38 +0,0 @@
-{ compiler, extraOverrides ? (final: prev: { }) }:
-
-self: super:
-let
-  overrides =
-    final: prev:
-    rec {
-      protolude =
-        prev.callHackageDirect
-          {
-            pkg = "protolude";
-            ver = "0.3.0";
-            sha256 = "0iwh4wsjhb7pms88lw1afhdal9f86nrrkkvv65f9wxbd1b159n72";
-          } { };
-      # To get the sha256
-      # nix-prefetch-url --unpack https://hackage.haskell.org/package/hasql-notifications-0.1.0.0/hasql-notifications-0.1.0.0.tar.gz
-      hasql-notifications =
-        self.haskell.lib.overrideCabal
-          (
-            prev.callHackageDirect
-              {
-                pkg = "hasql-notifications";
-                ver = "0.1.0.0";
-                sha256 = "1z17gsqvvzzi0yipc3qy3jz8vzpww4vsc4vaj2kbzr2mfliq6fx3";
-              } { }
-          )
-          (old: { doCheck = false; });
-    } // extraOverrides final prev;
-in
-{
-  haskell =
-    super.haskell // {
-      packages = super.haskell.packages // {
-        "${compiler}" =
-          super.haskell.packages."${compiler}".override { inherit overrides; };
-      };
-    };
-}