devshell: remove dependency on clan-cli derivation

The devShell depended on clan-cli due to it being included as a dependency in the treefmt config. This is not optimal because this makes the devshell rebuild unnecessary often and also lead to build failures of the dev-shell if the clan-cli code is in a broken state (git rebasing, or during development etc.)

devShell-python.nix

@@ -15,11 +15,9 @@
         ps:
         clan-cli.propagatedBuildInputs
         ++ clan-cli.devDependencies
-        ++ [
-          ps.pip
-          # clan-vm-manager deps
-          ps.pygobject3
-        ]
+        ++ [ ps.pip ]
+        ++ [ clan-vm-manager.externalPythonDeps ]
+        # clan-vm-manager deps
       );
       linuxOnlyPackages = lib.optionals pkgs.stdenv.isLinux [ pkgs.xdg-utils ];
     in

formatter.nix

@@ -10,7 +10,8 @@
       treefmt.programs.mypy.enable = true;
       treefmt.programs.mypy.directories = {
         "pkgs/clan-cli".extraPythonPackages = self'.packages.clan-cli.pytestDependencies;
-        "pkgs/clan-vm-manager".extraPythonPackages = self'.packages.clan-vm-manager.propagatedBuildInputs;
+        "pkgs/clan-vm-manager".extraPythonPackages =
+          self'.packages.clan-vm-manager.externalPythonDeps ++ self'.packages.clan-cli.pytestDependencies;
       };
 
       treefmt.settings.formatter.nix = {

pkgs/clan-vm-manager/default.nix

@@ -24,7 +24,7 @@ let
     mimeTypes = [ "x-scheme-handler/clan" ];
   };
 in
-python3.pkgs.buildPythonApplication {
+python3.pkgs.buildPythonApplication rec {
   name = "clan-vm-manager";
   src = source;
   format = "pyproject";
@@ -51,13 +51,19 @@ python3.pkgs.buildPythonApplication {
   # We need to propagate the build inputs to nix fmt / treefmt
   propagatedBuildInputs = [
     (python3.pkgs.toPythonModule clan-cli)
-    pygobject3
-    pygobject-stubs
+    passthru.externalPythonDeps
   ];
 
   # also re-expose dependencies so we test them in CI
   passthru = {
     inherit desktop-file;
+    # Keep external dependencies in a separate lists to refer to thm elsewhere
+    # This helps avoiding issues like dev-shells accidentally depending on
+    #   nix derivations of local packages.
+    externalPythonDeps = [
+      pygobject3
+      pygobject-stubs
+    ];
     tests = {
       clan-vm-manager-no-breakpoints = runCommand "clan-vm-manager-no-breakpoints" { } ''
         if grep --include \*.py -Rq "breakpoint()" ${source}; then

pkgs/clan-vm-manager/pyproject.toml

@@ -22,6 +22,10 @@ disallow_untyped_calls = true
 disallow_untyped_defs = true
 no_implicit_optional = true
 
+[[tool.mypy.overrides]]
+module = "clan_cli.*"
+ignore_missing_imports = true
+
 [tool.ruff]
 target-version = "py311"
 line-length = 88