add pkgs support to static-nix-shell and use it for gpodder

overlays/pkgs.nix

@@ -2,6 +2,7 @@
   with next;
   let
     sane = rec {
+      sane-lib = import ../modules/lib next;
       #### my own, non-upstreamable packages:
       static-nix-shell = callPackages ../pkgs/static-nix-shell { };
       sane-scripts = callPackage ../pkgs/sane-scripts { };

pkgs/gpodder-configured/default.nix

@@ -3,26 +3,20 @@
 , gpodder
 , makeWrapper
 , python3
+, static-nix-shell
 , symlinkJoin
 }:
 
 let
-  pyEnv = python3.withPackages (_ps: [ gnome-feeds.listparser ]);
-  remove-extra = stdenv.mkDerivation {
+  remove-extra = static-nix-shell.mkPython3Bin {
     pname = "gpodder-remove-extra";
-    version = "0.1.0";
-
     src = ./.;
-
-    patchPhase = ''
-      substituteInPlace ./remove_extra.py \
-        --replace "#!/usr/bin/env nix-shell" "#!${pyEnv.interpreter}"
-    '';
-
-    installPhase = ''
-      mkdir -p $out/bin
-      mv remove_extra.py $out/bin/gpodder-remove-extra
-    '';
+    pyPkgs = _ps: {
+      "gnome-feeds.listparser" = gnome-feeds.listparser;
+    };
+    pkgs = {
+      inherit gpodder;
+    };
   };
 in
 # we use a symlinkJoin so that we can inherit the .desktop and icon files from the original gPodder

pkgs/gpodder-configured/gpodder-remove-extra

@@ -1,5 +1,5 @@
 #!/usr/bin/env nix-shell
-#!nix-shell -i python3 -p "python3.withPackages (ps: [gnome-feeds.listparser])" -p gpodder
+#!nix-shell -i python3 -p "python3.withPackages (ps: [ gnome-feeds.listparser ])" -p gpodder
 
 from dataclasses import dataclass, field
 import listparser

pkgs/static-nix-shell/default.nix

@@ -1,30 +1,67 @@
-{ stdenv
+{ pkgs
+, lib
 , python3
+, sane-lib
+, stdenv
 }:
 
-{
+let
+  inherit (builtins) attrNames attrValues concatStringsSep map typeOf;
+  inherit (lib) concatMapAttrs;
+  inherit (sane-lib) mapToAttrs;
+  pkgs' = pkgs;
+in {
   # transform a file which uses `#!/usr/bin/env nix-shell` shebang with a `python3` interpreter
-  # into a derivation that can be built statically
-  mkPython3Bin = { pname, pyPkgs ? [], srcPath ? pname, ... }@attrs: stdenv.mkDerivation (
+  # into a derivation that can be built statically.
+  #
+  # pkgs and pyPkgs may take the following form:
+  # - [ "pkgNameA" "pkgNameB" ... ]
+  # - { pkgNameA = pkgValueA; pkgNameB = pkgValueB; ... }
+  # - ps: <evaluate to one of the above exprs>
+  #
+  # for pyPkgs, names are assumed to be relative to `"ps"` if specified in list form.
+  mkPython3Bin = { pname, pkgs ? {}, pyPkgs ? {}, srcPath ? pname, ... }@attrs:
     let
-      evalPyPkgs = ps: builtins.map (name: ps."${name}") pyPkgs;
-      pyEnv = python3.withPackages evalPyPkgs;
-      pyPkgsStr = builtins.concatStringsSep " " (builtins.map (p: "ps.${p}") pyPkgs);
-    in {
+      # create an attrset of
+      #   <name> = expected string in the nix-shell invocation
+      #   <value> = package to provide
+      pkgsToAttrs = prefix: pkgSet: expr: ({
+        "lambda" = expr: pkgsToAttrs prefix pkgSet (expr pkgSet);
+        "list" = expr: mapToAttrs (pname: {
+          name = prefix + pname;
+          value = pkgSet."${pname}";
+        }) expr;
+        "set" = expr: expr;
+      })."${typeOf expr}" expr;
+      pyEnv = python3.withPackages (ps: attrValues (
+        pkgsToAttrs "ps." ps pyPkgs
+      ));
+      pyPkgsStr = concatStringsSep " " (attrNames (
+        pkgsToAttrs "ps." {} pyPkgs
+      ));
+
+      pkgsAsAttrs = pkgsToAttrs "" pkgs' pkgs;
+      pkgsEnv = attrValues pkgsAsAttrs;
+      pkgsStr = concatStringsSep "" (map
+        (pname: " -p ${pname}")
+        (attrNames pkgsAsAttrs)
+      );
+    in stdenv.mkDerivation ({
       version = "0.1.0";  # default version
       patchPhase = ''
         substituteInPlace ${srcPath} \
           --replace '#!/usr/bin/env nix-shell' '#!${pyEnv.interpreter}' \
           --replace \
-            '#!nix-shell -i python3 -p "python3.withPackages (ps: [ ${pyPkgsStr} ])"' \
+            '#!nix-shell -i python3 -p "python3.withPackages (ps: [ ${pyPkgsStr} ])"${pkgsStr}' \
             '# nix deps evaluated statically'
       '';
+      runtimeDependencies = pkgsEnv;
       installPhase = ''
         mkdir -p $out/bin
         mv ${srcPath} $out/bin/${srcPath}
         # ensure that all nix-shell references were substituted
         ! grep nix-shell $out/bin/${srcPath}
       '';
-    } // attrs
+    } // (removeAttrs attrs [ "pkgs" "pyPkgs" "srcPath" ])
   );
 }