fix: improve unused deps detection somewhat

Signed-off-by: Christina Sørensen <ces@fem.gg>

.github/workflows/unit-tests.yml

@@ -19,13 +19,12 @@ jobs:
     name: Run cargo shear
     runs-on: ubuntu-latest
     steps:
-      - name: Checkout repository
-        uses: actions/checkout@v4
-      - name: Install Rust toolchain
-        uses: dtolnay/rust-toolchain@stable
-      - name: Install cargo-shear
-        run: cargo install cargo-shear
-      - name: Run check for unused dependencies
+      - uses: actions/checkout@v4
+      - name: Install Nix
+        uses: DeterminateSystems/nix-installer-action@v17
+      - name: Enter DevShell
+        run: nix develop
+      - name: Nix Flake Check
         run: cargo shear
   security_audit:
     runs-on: ubuntu-latest

flake.nix

@@ -182,8 +182,15 @@
                 "cargo-shear" = {
                   enable = true;
                   name = "Check for unused dependencies";
-                  entry = pkgs.lib.getExe pkgs.cargo-shear;
-                  pass_filenames = false;
+                  extraPackages = [ toolchain ];
+                  files = "\\.(rs|toml)$";
+                  entry = pkgs.lib.getExe (
+                    pkgs.writeShellScriptBin "cargo-shear-hook" ''
+                         set -e
+                         export CARGO_NET_OFFLINE=true
+                         ${pkgs.lib.getExe pkgs.cargo-shear} "$@"
+                      . ''
+                  );
                 };
               };
             };