Use a non-versioned filename for our nixpkgs pin.

default.nix

-{ pkgs ? import ./nixpkgs-2105.nix { } }:
+{ pkgs ? import ./nixpkgs.nix { } }:
 {
   # Render the project documentation source to some presentation format (ie,
   # html) with Sphinx.

morph/lib/default.nix

@@ -17,7 +17,7 @@
   # installed, as well as the NixOS module set that is used.
   # This is intended to be used in a grid definition like:
   #     network = { ... ; inherit (gridlib) pkgs; ... }
-  pkgs = import ../../nixpkgs-2105.nix {
+  pkgs = import ../../nixpkgs.nix {
     # Ensure that configuration of the system where this runs
     # doesn't leak into what we build.
     # See https://github.com/NixOS/nixpkgs/issues/62513

nixos/modules/update-deployment

@@ -72,14 +72,14 @@ EOF
 ssh -o StrictHostKeyChecking=no "$(hostname).$(domainname)" ":"
 
 # Set nixpkgs to our preferred version for the morph build.  Annoyingly, we
-# can't just use nixpkgs-2105.nix as our nixpkgs because some code (in morph,
+# can't just use nixpkgs.nix as our nixpkgs because some code (in morph,
 # at least) wants <nixpkgs> to be a fully-resolved path to a nixpkgs tree.
 # For example, morph evaluated `import <nixpkgs/lib>` which would turn into
-# something like `import nixpkgs-2105.nix/lib` which is nonsense.
+# something like `import nixpkgs.nix/lib` which is nonsense.
 #
 # So instead, import our nixpkgs which forces it to be instantiated in the
 # store, then ask for its path, then set NIX_PATH to that.
-export NIX_PATH="nixpkgs=$(nix eval "(import ${CHECKOUT}/nixpkgs-2105.nix { }).path")"
+export NIX_PATH="nixpkgs=$(nix eval "(import ${CHECKOUT}/nixpkgs.nix { }).path")"
 
 # Attempt to update just this host.  Choose the morph grid definition matching
 # the grid we belong to and limit the morph deployment update to the host

nixpkgs-2105.json → nixpkgs.json

 {
-  "name": "release2105",
+  "name": "source",
   "url": "https://releases.nixos.org/nixos/21.05/nixos-21.05.4717.df123677560/nixexprs.tar.xz",
   "sha256": "02zkhiwl3lwhk9fkmcbcfr927w135xdrgp6z7g804symbd1jcwal"
-}
\ No newline at end of file
+}

nixpkgs-2105.nix → nixpkgs.nix

-import (builtins.fetchTarball (builtins.fromJSON (builtins.readFile ./nixpkgs-2105.json)))
+import (builtins.fetchTarball (builtins.fromJSON (builtins.readFile ./nixpkgs.json)))

shell.nix

 let
-  release2105 = import ./nixpkgs-2105.nix { };
+  pinned-pkgs = import ./nixpkgs.nix { };
 in
-{ pkgs ? release2105, lib ? pkgs.lib, python ? pkgs.python3 }:
+{ pkgs ? pinned-pkgs, lib ? pkgs.lib, python ? pkgs.python3 }:
 let
   tools = pkgs.callPackage ./tools {};
 in
@@ -10,7 +10,7 @@ pkgs.mkShell {
   # first adds that path to the store, and then interpolates the store path
   # into the string.  We use `builtins.toString` to convert the path to a
   # string without copying it to the store before interpolating. Either the
-  # path is already in the store (e.g. when `pkgs` is `release2105`) so we
+  # path is already in the store (e.g. when `pkgs` is `pinned-pkgs`) so we
   # avoid making a second copy with a longer name, or the user passed in local
   # path (e.g. a checkout of nixpkgs) and we point at it directly, rather than
   # a snapshot of it.

tools/update-nixpkgs

@@ -37,7 +37,7 @@ def main():
         "repo_file",
         metavar="repo-file",
         nargs="?",
-        default=Path(__file__).parent.with_name("nixpkgs-2105.json"),
+        default=Path(__file__).parent.with_name("nixpkgs.json"),
         type=Path,
         help="JSON file with pinned configuration.",
     )