Add experimental support for plugin closures

default.nix

@@ -22,6 +22,9 @@ let
   # Get license by id falling back to input string
   getLicenseBySpdxId = spdxId: spdxLicenses.${spdxId} or spdxId;
 
+  # Experimental withPlugins functionality
+  toPluginAble = (import ./plugins.nix { inherit pkgs lib; }).toPluginAble;
+
   /*
      Returns an attrset { python, poetryPackages, pyProject, poetryLock } for the given pyproject/lockfile.
   */
@@ -106,6 +109,8 @@ let
                   # The canonical name is setuptools-scm
                   setuptools-scm = super.setuptools_scm;
 
+                  __toPluginAble = toPluginAble self;
+
                   inherit (hooks) pipBuildHook removePathDependenciesHook poetry2nixFixupHook;
                 }
             )

plugins.nix

@@ -0,0 +1,70 @@
+{ pkgs, lib }:
+let
+  inherit (pkgs) stdenv;
+
+  mkPluginDrv =
+    { self
+    , plugins
+    , drv
+    , postInstall ? ""
+    , nativeBuildInputs ? [ ]
+    , buildInputs ? [ ]
+    }:
+    let
+      env = self.python.withPackages (ps: plugins);
+    in
+    stdenv.mkDerivation {
+      pname = drv.pname + "-with-plugins";
+
+      inherit (drv) src version meta;
+
+      buildInputs = drv.buildInputs ++ drv.propagatedBuildInputs ++ buildInputs;
+      nativeBuildInputs = drv.nativeBuildInputs ++ nativeBuildInputs;
+
+      dontConfigure = true;
+      dontBuild = true;
+      dontUsePythonRecompileBytecode = true;
+
+      passthru = {
+        inherit (drv.passthru) withPlugins;
+        inherit plugins;
+      };
+
+      # Link bin/ from environment, but only if it's in a plugin
+      installPhase = ''
+        runHook preInstall
+
+        mkdir -p $out/bin
+
+        for bindir in ${lib.concatStringsSep " " (map (d: "${lib.getBin d}/bin") plugins)}; do
+          for bin in $bindir/*; do
+            ln -s ${env}/bin/$(basename $bin) $out/bin/
+          done
+        done
+
+        runHook postInstall
+      '';
+
+      inherit postInstall;
+    };
+
+in
+{
+
+  # Provide the `withPlugins` function
+  toPluginAble = self: { drv
+                       , finalDrv
+                       , postInstall ? ""
+                       , nativeBuildInputs ? [ ]
+                       , buildInputs ? [ ]
+                       }: drv.overridePythonAttrs (old: {
+    passthru = old.passthru // {
+      withPlugins = pluginFn: mkPluginDrv {
+        plugins = [ finalDrv ] ++ pluginFn self;
+        inherit self postInstall nativeBuildInputs buildInputs;
+        drv = finalDrv;
+      };
+    };
+  });
+
+}