.gitea/workflows/ci.yaml

@@ -2,18 +2,18 @@
 # plus an explicit per-host evaluation pass for granular output.
 name: CI
 
+# Deliberately no `paths:` filter. This job is a required status check on main,
+# and a path-filtered workflow is *skipped* (never runs) for PRs that touch no
+# matching file -- which leaves the required check pending forever and blocks the
+# merge (e.g. a .renovaterc.json-only change). So the workflow always runs and
+# always reports. To avoid burning a full Nix evaluation on changes that can't
+# affect it, the "detect" step below diffs the PR and the heavy steps run only
+# when a .nix file, flake.lock, or this workflow changed; otherwise they skip and
+# the job still passes. The required check is therefore always green-reportable.
 on:
   push:
     branches: [main]
-    paths:
-      - "**.nix"
-      - "flake.lock"
-      - ".gitea/workflows/ci.yaml"
   pull_request:
-    paths:
-      - "**.nix"
-      - "flake.lock"
-      - ".gitea/workflows/ci.yaml"
 
 jobs:
   flake:
@@ -21,8 +21,39 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@df4cb1c069e1874edd31b4311f1884172cec0e10 # v6
+        with:
+          # Full history so the detect step can diff the PR against its base.
+          fetch-depth: 0
+
+      # Decide whether the Nix steps need to run. On a pull_request, diff the PR
+      # against its base and look for files that can affect the flake: any .nix,
+      # the lockfile, or this workflow. On any other event (push to main) always
+      # run. The job itself always succeeds, so the required status check is
+      # reported even when the heavy steps are skipped.
+      - name: Detect Nix-relevant changes
+        id: detect
+        run: |
+          set -euo pipefail
+          if [ "${{ github.event_name }}" != "pull_request" ]; then
+            echo "Event ${{ github.event_name }}: running full checks."
+            echo "run=true" >> "$GITHUB_OUTPUT"
+            exit 0
+          fi
+          base='${{ github.event.pull_request.base.sha }}'
+          head='${{ github.event.pull_request.head.sha }}'
+          changed=$(git diff --name-only "$base...$head")
+          echo "Changed files:"
+          echo "$changed"
+          if echo "$changed" | grep -Eq '(\.nix$|^flake\.lock$|^\.gitea/workflows/ci\.yaml$)'; then
+            echo "Nix-relevant changes found: running checks."
+            echo "run=true" >> "$GITHUB_OUTPUT"
+          else
+            echo "No Nix-relevant changes: skipping checks (job still passes)."
+            echo "run=false" >> "$GITHUB_OUTPUT"
+          fi
 
       - name: Install Nix
+        if: steps.detect.outputs.run == 'true'
         uses: cachix/install-nix-action@8aa03977d8d733052d78f4e008a241fd1dbf36b3 # v31
         with:
           extra_nix_config: |
@@ -34,6 +65,7 @@ jobs:
       # Runs every flake check: treefmt formatting, deadnix, statix, and the
       # pre-commit hooks (so a --no-verify commit can't ship unlinted).
       - name: Flake check
+        if: steps.detect.outputs.run == 'true'
         run: nix flake check --print-build-logs
 
       # Evaluate (not build) each host's toplevel so eval errors fail CI cheaply.
@@ -44,6 +76,7 @@ jobs:
       # nixos/darwinConfigurations) rather than hard-coded, so adding or removing
       # a host needs no change to this workflow.
       - name: Evaluate NixOS host configurations
+        if: steps.detect.outputs.run == 'true'
         run: |
           set -euo pipefail
           hosts=$(nix eval --raw '.#nixosConfigurations' \
@@ -56,6 +89,7 @@ jobs:
           done
 
       - name: Evaluate Darwin host configurations
+        if: steps.detect.outputs.run == 'true'
         run: |
           set -euo pipefail
           hosts=$(nix eval --raw '.#darwinConfigurations' \