fix(v1): move writers to pkgs

v1/nix/modules/flake-parts/writers.nix

@@ -4,7 +4,9 @@
     lib,
     pkgs,
     ...
-  }: {
+  }: let
+    writers = pkgs.callPackage ../../pkgs/writers {};
+  in {
     options.writers = {
       writePureShellScript = lib.mkOption {
         type = lib.types.functionTo lib.types.anything;
@@ -14,87 +16,12 @@
       };
     };
 
-    /*
-    create a script that runs in a `pure` environment, in the sense that:
-    - PATH only contains exactly the packages passed via the PATH arg
-    - NIX_PATH is set to the path of the current `pkgs`
-    - TMPDIR is set up and cleaned up even if the script fails
-    - out, if set, is kept as-is
-    - all environment variables are unset, except:
-    - the ones listed in `keepVars` below
-    - ones listed via the KEEP_VARS variable
-    - the behavior is similar to `nix-shell --pure`
-    */
-    config.writers = let
-      mkScript = PATH: script: ''
-        #!${pkgs.bash}/bin/bash
-        set -Eeuo pipefail
-
-        export PATH="${lib.makeBinPath PATH}"
-        export NIX_PATH=nixpkgs=${pkgs.path}
-
-        export TMPDIR=$(${pkgs.coreutils}/bin/mktemp -d)
-
-        trap "${pkgs.coreutils}/bin/chmod -R +w '$TMPDIR'; ${pkgs.coreutils}/bin/rm -rf '$TMPDIR'" EXIT
-
-        if [ -z "''${IMPURE:-}" ]; then
-          ${cleanEnv}
-        fi
-
-        ${script}
-      '';
-
-      # list taken from nix source: src/nix-build/nix-build.cc
-      keepVars = lib.concatStringsSep " " [
-        "HOME"
-        "XDG_RUNTIME_DIR"
-        "USER"
-        "LOGNAME"
-        "DISPLAY"
-        "WAYLAND_DISPLAY"
-        "WAYLAND_SOCKET"
-        "PATH"
-        "TERM"
-        "IN_NIX_SHELL"
-        "NIX_SHELL_PRESERVE_PROMPT"
-        "TZ"
-        "PAGER"
-        "NIX_BUILD_SHELL"
-        "SHLVL"
-        "http_proxy"
-        "https_proxy"
-        "ftp_proxy"
-        "all_proxy"
-        "no_proxy"
-
-        # We want to keep out own variables as well
-        "out"
-        "IMPURE"
-        "KEEP_VARS"
-        "NIX_PATH"
-        "TMPDIR"
-      ];
-
-      cleanEnv = ''
-
-        KEEP_VARS="''${KEEP_VARS:-}"
-
-        unsetVars=$(
-          ${pkgs.coreutils}/bin/comm \
-            <(${pkgs.gawk}/bin/awk 'BEGIN{for(v in ENVIRON) print v}' | ${pkgs.coreutils}/bin/cut -d = -f 1 | ${pkgs.coreutils}/bin/sort) \
-            <(echo "${keepVars} $KEEP_VARS" | ${pkgs.coreutils}/bin/tr " " "\n" | ${pkgs.coreutils}/bin/sort) \
-            -2 \
-            -3
-        )
-
-        unset $unsetVars
-      '';
-    in {
-      writePureShellScript = PATH: script:
-        pkgs.writeScript "script.sh" (mkScript PATH script);
-
-      writePureShellScriptBin = binName: PATH: script:
-        pkgs.writeScriptBin binName (mkScript PATH script);
+    config.writers = {
+      inherit
+        (writers)
+        writePureShellScript
+        writePureShellScriptBin
+        ;
     };
   };
 }

v1/nix/pkgs/writers/default.nix

@@ -0,0 +1,96 @@
+{
+  lib,
+  bash,
+  coreutils,
+  gawk,
+  path, # nixpkgs path
+  writeScript,
+  writeScriptBin,
+  ...
+}: let
+  /*
+  create a script that runs in a `pure` environment, in the sense that:
+  - PATH only contains exactly the packages passed via the PATH arg
+  - NIX_PATH is set to the path of the current `pkgs`
+  - TMPDIR is set up and cleaned up even if the script fails
+  - out, if set, is kept as-is
+  - all environment variables are unset, except:
+  - the ones listed in `keepVars` below
+  - ones listed via the KEEP_VARS variable
+  - the behavior is similar to `nix-shell --pure`
+  */
+  writePureShellScript = PATH: script:
+    writeScript "script.sh" (mkScript PATH script);
+
+  writePureShellScriptBin = binName: PATH: script:
+    writeScriptBin binName (mkScript PATH script);
+
+  mkScript = PATH: script: ''
+    #!${bash}/bin/bash
+    set -Eeuo pipefail
+
+    export PATH="${lib.makeBinPath PATH}"
+    export NIX_PATH=nixpkgs=${path}
+
+    export TMPDIR=$(${coreutils}/bin/mktemp -d)
+
+    trap "${coreutils}/bin/chmod -R +w '$TMPDIR'; ${coreutils}/bin/rm -rf '$TMPDIR'" EXIT
+
+    if [ -z "''${IMPURE:-}" ]; then
+      ${cleanEnv}
+    fi
+
+    ${script}
+  '';
+
+  # list taken from nix source: src/nix-build/nix-build.cc
+  keepVars = lib.concatStringsSep " " [
+    "HOME"
+    "XDG_RUNTIME_DIR"
+    "USER"
+    "LOGNAME"
+    "DISPLAY"
+    "WAYLAND_DISPLAY"
+    "WAYLAND_SOCKET"
+    "PATH"
+    "TERM"
+    "IN_NIX_SHELL"
+    "NIX_SHELL_PRESERVE_PROMPT"
+    "TZ"
+    "PAGER"
+    "NIX_BUILD_SHELL"
+    "SHLVL"
+    "http_proxy"
+    "https_proxy"
+    "ftp_proxy"
+    "all_proxy"
+    "no_proxy"
+
+    # We want to keep out own variables as well
+    "out"
+    "IMPURE"
+    "KEEP_VARS"
+    "NIX_PATH"
+    "TMPDIR"
+  ];
+
+  cleanEnv = ''
+
+    KEEP_VARS="''${KEEP_VARS:-}"
+
+    unsetVars=$(
+      ${coreutils}/bin/comm \
+        <(${gawk}/bin/awk 'BEGIN{for(v in ENVIRON) print v}' | ${coreutils}/bin/cut -d = -f 1 | ${coreutils}/bin/sort) \
+        <(echo "${keepVars} $KEEP_VARS" | ${coreutils}/bin/tr " " "\n" | ${coreutils}/bin/sort) \
+        -2 \
+        -3
+    )
+
+    unset $unsetVars
+  '';
+in {
+  inherit
+    writePureShellScript
+    writePureShellScriptBin
+    ;
+}