ci: only build uncached derivations

.github/workflows/test.yml

@@ -45,7 +45,7 @@ jobs:
         name: crane
         authToken: '${{ secrets.CACHIX_AUTH_TOKEN }}'
     - name: flake checks
-      run: nix flake check --accept-flake-config --keep-going --print-build-logs ${{ matrix.nixpkgs-override }}
+      run: nix develop .# --command ./ci/fast-flake-check.sh ${{ matrix.nixpkgs-override }} -- --keep-going
     - name: extra tests
       run: nix develop --accept-flake-config ${{ matrix.nixpkgs-override }} --command ./extra-tests/test.sh
 
@@ -82,7 +82,7 @@ jobs:
         for f in $(find examples -maxdepth 1 -mindepth 1 -type d ${{ matrix.filter }}); do
           pushd "${f}"
           echo "validating ${f}"
-          nix flake check --accept-flake-config --print-build-logs --override-input crane ../.. ${{ matrix.nixpkgs-override }}
+          nix develop .# --command ./ci/fast-flake-check.sh --override-input crane ../.. ${{ matrix.nixpkgs-override }} -- --keep-going
           popd
         done
 

.gitignore

@@ -1,4 +1,5 @@
 /examples/*/flake.lock
+gcroot
 result*
 target/
 /extra-tests/*/flake.lock

ci/fast-flake-check.sh

@@ -0,0 +1,22 @@
+#!/usr/bin/env bash
+curSystem=$(nix eval --raw --impure --expr builtins.currentSystem)
+
+nixEvalJobsArgs=()
+while [[ $# -ge 0 ]]; do
+  arg="$1"
+  shift 1
+
+  if [[ "${arg}" == '--' ]]; then
+    break
+  fi
+
+  nixEvalJobsArgs+=("$arg")
+done
+
+nix-eval-jobs \
+  --gc-roots-dir gcroot \
+  --check-cache-status \
+  --flake ".#checks.${curSystem}" \
+  "${nixEvalJobsArgs[@]}" \
+  | jq -r 'select(.isCached | not).drvPath as $drvPath | "\($drvPath)^*"' \
+  | xargs --no-run-if-empty nix build --no-link --print-build-logs "$@"

flake.nix

@@ -126,6 +126,7 @@
           nativeBuildInputs = with pkgs; [
             jq
             mdbook
+            nix-eval-jobs
             nixpkgs-fmt
           ];
         };