feat: Statically link libiconv on aarch64-darwin; Test static binar…

…y in CI (#158)

* omnix-cli: Statically link libiconv

* static libiconv only on aarch64-darwin

* ci: Test static binary

* actions/*-artifact@v4

* chmod om; upload artifact earlier

* build and upload artifact on non x86_64-darwin

* check nix installation before testing static binary

* add description for error on x86_64-darwin upon evaluating static libiconv

* be explicit about the path from where the binary comes

* debug om_static_binary_path

* wrap om_static_binary_path in actions env syntax

* remove debug step

.github/workflows/ci.yaml

@@ -37,6 +37,15 @@ jobs:
       - name: Check static binary size
         if: matrix.system == 'x86_64-linux'
         run: nix run .#check-closure-size
+      - name: nix build
+        if: matrix.system != 'x86_64-darwin'
+        run: echo "om_static_binary_path=$(nix build --no-link --print-out-paths)" >> "$GITHUB_ENV"
+      - name: Upload om static binary
+        if: matrix.system != 'x86_64-darwin'
+        uses: actions/upload-artifact@v4
+        with:
+          name: om-${{ matrix.system }}
+          path: ${{ env.om_static_binary_path }}/bin/om
       - name: nix run
         run: nix run . -- --help
       # First, build the repos used in the test to cache them locally, so as
@@ -61,3 +70,29 @@ jobs:
       - name: Push to cachix
         if: github.ref == 'refs/heads/main'
         run: nix --option system "${{ matrix.system }}" run .#cachix-push
+  static-binary-check:
+    needs: checks
+    runs-on: ${{ matrix.system }}
+    strategy:
+      matrix:
+        system: [ ubuntu-latest, macos-latest ]
+    steps:
+      - name: Donwload om static binary
+        uses: actions/download-artifact@v4
+        with:
+          name: om-${{ matrix.system == 'ubuntu-latest' && 'x86_64-linux' || matrix.system == 'macos-latest' && 'aarch64-darwin' || matrix.system }}
+      - name: Check nix installation
+        run: |
+          if which nix; then
+            echo "nix is installed, exiting"
+            exit 1
+          elif test -d /nix; then
+            echo "/nix is present, exiting"
+            exit 1
+          else
+            echo "nix is not installed"
+          fi
+      - name: Run om static binary
+        run: |
+          chmod +x ./om
+          ./om --help

nix/rust.nix

@@ -39,7 +39,12 @@
                   Security
                   SystemConfiguration
                 ] ++ [
-                  libiconv
+                  # Packages from `pkgsStatic` require cross-compilation support for the target platform,
+                  # which is not yet available for `x86_64-apple-darwin` in nixpkgs. Upon trying to evaluate
+                  # a static package for `x86_64-apple-darwin`, you may see an error like:
+                  #
+                  # > error: don't yet have a `targetPackages.darwin.LibsystemCross for x86_64-apple-darwin`
+                  (if (stdenv.isDarwin && stdenv.isAarch64) then pkgsStatic.libiconv else libiconv)
                   pkg-config
                 ];
                 buildInputs = lib.optionals pkgs.stdenv.isDarwin
@@ -60,9 +65,9 @@
                   description = "Command-line interface for Omnix";
                   mainProgram = "om";
                 };
+                CARGO_BUILD_RUSTFLAGS = "-C target-feature=+crt-static";
               } //
               lib.optionalAttrs pkgs.stdenv.isLinux {
-                CARGO_BUILD_RUSTFLAGS = "-C target-feature=+crt-static";
                 CARGO_BUILD_TARGET = "x86_64-unknown-linux-musl";
               };
             };