Drop support for dir-locals.nix, <nixpkgs>, etc.

In the spirit of Marie Kondo, I'm tidying up!

TL;DR:
- Prefer .envrc `use_nix` and delete all dir-locals.nix files
- Remove ~all references to <nixpkgs>, <unstable>, <depot> and prefer
  referencing each with briefcase.third_party.{pkgs,unstable,depot}
- Delete nixBufferFromShell function since I was only using that in
  dir-locals.nix files

.envrc

@@ -1,10 +1,8 @@
-export BRIEFCASE="$(realpath ~/briefcase)"
+export BRIEFCASE="$(realpath .)"
-export DEPOT="$(realpath ~/depot)"
+# I'm ensuring that $NIX_PATH is mostly empty, so that I only depend on
-export NIXPKGS="$(realpath ~/nixpkgs)"
+# <briefcase> for now.
-# I'm ensuring that $NIX_PATH is unset to avoid the anti-pattern of depending on
+# For more information on the NIX_PATH anti-pattern, see here:
-# <nixpkgs>, <briefcase>, <depot>, <unstable>.
-# For more information about setting this to "", see:
 # https://nix.dev/tutorials/towards-reproducibility-pinning-nixpkgs.html#pinning-nixpkgs
-export NIX_PATH="";
+export NIX_PATH="briefcase=$BRIEFCASE";
 export DESKTOP="zeno.lon.corp.google.com";
 export LAPTOP="seneca";

assessments/dotted-squares/.envrc

@@ -1 +1,2 @@
+source_up
 use_nix

boilerplate/clojure/.envrc

@@ -0,0 +1,2 @@
+source_up
+use_nix

boilerplate/clojure/dir-locals.nix

@@ -1,3 +0,0 @@
-let
-  briefcase = import <briefcase> {};
-in briefcase.utils.nixBufferFromShell ./shell.nix

boilerplate/clojure/shell.nix

@@ -1,5 +1,6 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
+  pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
   buildInputs = with pkgs; [
     leiningen

boilerplate/elm/.envrc

@@ -0,0 +1,2 @@
+source_up
+use_nix

boilerplate/elm/dir-locals.nix

@@ -1,3 +0,0 @@
-let
-  briefcase = import <briefcase> {};
-in briefcase.utils.nixBufferFromShell ./shell.nix

boilerplate/elm/shell.nix

@@ -1,9 +1,10 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
+  pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
-  buildInputs = with pkgs; [
+  buildInputs = with pkgs.elmPackages; [
-    elmPackages.elm
+    elm
-    elmPackages.elm-format
+    elm-format
-    elmPackages.elm-live
+    elm-live
   ];
 }

boilerplate/typescript/.envrc

@@ -0,0 +1,2 @@
+source_up
+use_nix

boilerplate/typescript/dir-locals.nix

@@ -1,3 +0,0 @@
-let
-  briefcase = import <briefcase> {};
-in briefcase.utils.nixBufferFromShell ./shell.nix

boilerplate/typescript/shell.nix

@@ -1,5 +1,6 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
+  pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
   buildInputs = with pkgs; [
     nodejs

emacs/.emacs.d/snippets/nix-mode/shell-nix

@@ -2,9 +2,10 @@
 # name: shell.nix boilerplate
 # key: import
 # --
-with import <nixpkgs> {};
+let
-
+  briefcase = with import <briefcase> {};
-stdenv.mkDerivation {
+  pkgs = briefcase.third_party.pkgs;
+in stdenv.mkDerivation {
   name = "$1";
   buildInputs = [
     $2

emacs/.emacs.d/wpc/wpc-nix.el

@@ -59,7 +59,7 @@ This function was taken from @tazjin's depot and adapted for my monorepo.
   (interactive "sAttribute: ")
   (lexical-let* ((outbuf (get-buffer-create (format "*briefcase-out/%s*" attribute)))
          (errbuf (get-buffer-create (format "*briefcase-errors/%s*" attribute)))
-         (expression (format "let depot = import <depot> {}; briefcase = import <briefcase> {}; in depot.nix.buildLisp.sbclWith [ briefcase.%s ]" attribute))
+         (expression (format "let briefcase = import <briefcase> {}; in briefcase.third_party.depot.nix.buildLisp.sbclWith [ briefcase.%s ]" attribute))
          (command (list "nix-build" "-E" expression)))
     (message "Acquiring Lisp for <briefcase>.%s" attribute)
     (make-process :name (format "nix-build/%s" attribute)

go/.envrc

@@ -1 +1,2 @@
 source_up
+use_nix

go/dir-locals.nix

@@ -1,3 +0,0 @@
-let
-  briefcase = import <briefcase> {};
-in briefcase.utils.nixBufferFromShell ./shell.nix

go/shell.nix

@@ -1,9 +1,10 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
+  pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
-  buildInputs = [
+  buildInputs = with pkgs; [
-    pkgs.go
+    go
-    pkgs.goimports
+    goimports
-    pkgs.godef
+    godef
   ];
 }

haskell-file/.envrc

@@ -0,0 +1,2 @@
+source_up
+use_nix

haskell-file/shell.nix

@@ -1,9 +1,5 @@
-with import <nixpkgs> {};
+let
-
+  briefcase = import <briefcase> {};
-stdenv.mkDerivation {
+in briefcase.buildHaskell.shell {
-  name = "f-hs";
+  deps = hpkgs: [];
-  buildInputs = [
-    (pkgs.haskellPackages.ghcWithPackages (pkgs: [
-    ]))
-  ];
 }

playbooks/nix_gcr/cloud_run.nix

@@ -1,8 +1,4 @@
-{
+{ pkgs, depot, ... }:
-  pkgs ? import <nixpkgs> {},
-  depot ? import <depot> {},
-  ...
-}:
 
 pkgs.dockerTools.buildLayeredImage {
   name = "gemma";

scratch/deepmind/part_two/.envrc

@@ -1 +1,2 @@
 source_up
+use_nix

scratch/deepmind/part_two/dir-locals.nix

@@ -1,3 +0,0 @@
-let
-  briefcase = import <briefcase> {};
-in briefcase.utils.nixBufferFromShell ./shell.nix

scratch/deepmind/part_two/shell.nix

@@ -1,5 +1,6 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
+  pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
   buildInputs = with pkgs; [
     nodejs

scratch/groceries/.envrc

@@ -0,0 +1,2 @@
+source_up
+use_nix

scratch/groceries/shell.nix

@@ -1,8 +1,5 @@
 let
-  pkgs = import <unstable> {};
+  briefcase = import <briefcase> {};
-in pkgs.mkShell {
+in briefcase.buildHaskell.shell {
-  buildInputs = with pkgs; [
+  deps = hpkgs: [];
-    (haskellPackages.ghcWithPackages (hpkgs: with hpkgs; [
-    ]))
-  ];
 }

scratch/haskell-programming-from-first-principles/.envrc

@@ -0,0 +1,2 @@
+source_up
+use_nix

scratch/haskell-programming-from-first-principles/shell.nix

@@ -1,10 +1,8 @@
 let
-  pkgs = import <unstable> {};
+  briefcase = import <briefcase> {};
-in pkgs.mkShell {
+in briefcase.buildHaskell.shell {
-  buildInputs = with pkgs; [
+  deps = hpkgs: with hpkgs; [
-    (haskellPackages.ghcWithPackages (hpkgs: with hpkgs; [
+    quickcheck-simple
-      hpkgs.quickcheck-simple
+    checkers
-      hpkgs.checkers
-    ]))
   ];
 }

tools/monzo_ynab/.envrc

@@ -1,4 +1,5 @@
 source_up
+use_nix
 export monzo_client_id="$(pass show finance/monzo/client-id)"
 export monzo_client_secret="$(pass show finance/monzo/client-secret)"
 export ynab_personal_access_token="$(pass show finance/youneedabudget.com/personal-access-token)"

tools/monzo_ynab/dir-locals.nix

@@ -1,3 +0,0 @@
-let
-  briefcase = import <briefcase> {};
-in briefcase.utils.nixBufferFromShell ./shell.nix

tools/monzo_ynab/shell.nix

@@ -1,5 +1,6 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
+  pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
   buildInputs = [
     pkgs.go

tools/run/.envrc

@@ -1 +1,2 @@
 source_up
+use_nix

tools/run/dir-locals.nix

@@ -1,3 +0,0 @@
-let
-  briefcase = import <briefcase> {};
-in briefcase.utils.nixBufferFromShell ./shell.nix

tools/run/shell.nix

@@ -1,5 +1,6 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
+  pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
   buildInputs = with pkgs; [
     go

tools/url-blocker/.envrc

@@ -1 +1,2 @@
 source_up
+use_nix

tools/url-blocker/default.nix

@@ -1,8 +1,6 @@
-{ ... }:
+{ pkgs, ... }:
 
 let
-  pkgs = import <unstable> {};
-
   ghc = pkgs.haskellPackages.ghcWithPackages (hpkgs: [
     hpkgs.time
     hpkgs.aeson

tools/url-blocker/shell.nix

@@ -1,12 +1,10 @@
 let
-  pkgs = import <unstable> {};
+  briefcase = import <briefcase> {};
-in pkgs.mkShell {
+in briefcase.buildHaskell.shell {
-  buildInputs = with pkgs; [
+  deps = hpkgs: with hpkgs; [
-    (haskellPackages.ghcWithPackages (hpkgs: with hpkgs; [
+    time
-      time
+    aeson
-      aeson
+    either
-      either
+    hspec
-      hspec
-    ]))
   ];
 }

utils/default.nix

@@ -11,10 +11,4 @@
   wrapNonNixProgram = { path, as }: pkgs.writeShellScriptBin as ''
     exec ${path} "$@"
   '';
-
-  # Expose the buildInputs from a Nix shell to an Emacs buffer. Intended to be
-  # called from dir-locals.nix files.
-  nixBufferFromShell = path: let
-    shell = import path;
-  in pkgs.nixBufferBuilders.withPackages shell.buildInputs;
 }

website/blog/.envrc

@@ -1 +1,2 @@
 source_up
+use_nix

website/blog/shell.nix

@@ -1,7 +1,7 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
-in
+  pkgs = briefcase.third_party.pkgs;
-pkgs.mkShell {
+in pkgs.mkShell {
   buildInputs = with pkgs; [
     hugo
   ];

website/days-of-week-habits/.envrc

@@ -0,0 +1,2 @@
+source_up
+use_nix

website/days-of-week-habits/dir-locals.nix

@@ -1,3 +0,0 @@
-let
-  briefcase = import <briefcase> {};
-in briefcase.utils.nixBufferFromShell ./shell.nix

website/days-of-week-habits/shell.nix

@@ -1,5 +1,6 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
+  pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
   buildInputs = with pkgs; [
     nodejs

website/goals/.envrc

@@ -0,0 +1,2 @@
+source_up
+use_nix

website/goals/dir-locals.nix

@@ -1,3 +0,0 @@
-let
-  briefcase = import <briefcase> {};
-in briefcase.utils.nixBufferFromShell ./shell.nix

website/goals/shell.nix

@@ -1,5 +1,6 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
+  pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
   buildInputs = with pkgs; [
     nodejs

website/habitgarden/.envrc

@@ -0,0 +1,2 @@
+source_up
+use_nix

website/habitgarden/dir-locals.nix

@@ -1,3 +0,0 @@
-let
-  briefcase = import <briefcase> {};
-in briefcase.utils.nixBufferFromShell ./shell.nix

website/habitgarden/shell.nix

@@ -1,5 +1,6 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
+  pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
   buildInputs = with pkgs; [
     nodejs

website/sandbox/contentful/.envrc

@@ -1,3 +1,4 @@
 source_up
+use_nix
 export CONTENTFUL_SPACE_ID="$(pass show programming/contentful/space-id)"
 export CONTENTFUL_ACCESS_TOKEN="$(pass show programming/contentful/access-token)"

website/sandbox/contentful/default.nix

@@ -1,6 +1,6 @@
-let
+{ pkgs, ... }:
-  pkgs = import <nixpkgs> {};
+
-in pkgs.stdenv.mkDerivation {
+pkgs.stdenv.mkDerivation {
   name = "ideal-website";
   src = builtins.path { path = ./.; name = "contentful"; };
   buildInputs = with pkgs; [

website/sandbox/contentful/shell.nix

@@ -1,5 +1,6 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
+  pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
   buildInputs = with pkgs; [
     nodejs

website/sandbox/covid-uk/shell.nix

@@ -1,5 +1,6 @@
 let
-  pkgs = import <nixpkgs> {};
+  briefcase = import <briefcase> {};
+  pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
   buildInputs = with pkgs; [
     yarn

website/sandbox/learnpianochords/.envrc

@@ -0,0 +1,2 @@
+source_up
+use_nix

website/sandbox/learnpianochords/dir-locals.nix

@@ -1,3 +0,0 @@
-let
-  briefcase = import <briefcase> {};
-in briefcase.utils.nixBufferFromShell ./shell.nix

website/sandbox/learnpianochords/shell.nix

@@ -2,9 +2,9 @@ let
   briefcase = import <briefcase> {};
   pkgs = briefcase.third_party.pkgs;
 in pkgs.mkShell {
-  buildInputs = with pkgs; [
+  buildInputs = with pkgs.elmPackages; [
-    elmPackages.elm
+    elm
-    elmPackages.elm-format
+    elm-format
-    elmPackages.elm-live
+    elm-live
   ];
 }

zoo/.envrc

@@ -1 +1,2 @@
+source_up
 use_nix