ci: verify fork nightlies in pull requests (#9)

Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: incognitojam

.github/workflows/fork-nightly.yml

@@ -1,6 +1,7 @@
 name: Fork Nightly
 
 on:
+  pull_request:
   schedule:
     - cron: "23 */6 * * *"
   workflow_dispatch:
@@ -10,8 +11,8 @@ permissions:
   id-token: none
 
 concurrency:
-  group: fork-nightly
-  cancel-in-progress: false
+  group: fork-nightly-${{ github.event.pull_request.number || 'publish' }}
+  cancel-in-progress: ${{ github.event_name == 'pull_request' }}
 
 jobs:
   prepare:
@@ -30,7 +31,7 @@ jobs:
       - name: Checkout fork patch stack
         uses: actions/checkout@v6
         with:
-          ref: main
+          ref: ${{ github.event.pull_request.head.sha || 'main' }}
           fetch-depth: 0
           sparse-checkout: |
             /*
@@ -51,12 +52,13 @@ jobs:
           git fetch origin \
             '+refs/heads/nightly-candidate:refs/remotes/origin/nightly-candidate' || true
 
-          git switch -C nightly-candidate origin/main
+          git switch -C nightly-candidate HEAD
           git rebase upstream/main
 
           candidate_ref=$(git rev-parse HEAD)
           has_changes=true
-          if git rev-parse --verify refs/remotes/origin/nightly >/dev/null 2>&1 && \
+          if [[ "$GITHUB_EVENT_NAME" != "pull_request" ]] && \
+            git rev-parse --verify refs/remotes/origin/nightly >/dev/null 2>&1 && \
             git diff --quiet origin/nightly HEAD --; then
             has_changes=false
           fi
@@ -94,7 +96,9 @@ jobs:
 
       - id: release_meta
         name: Resolve nightly version
-        if: steps.candidate.outputs.has_changes == 'true'
+        if: >-
+          github.event_name != 'pull_request' &&
+          steps.candidate.outputs.has_changes == 'true'
         shell: bash
         env:
           CANDIDATE_REF: ${{ steps.candidate.outputs.ref }}
@@ -108,13 +112,17 @@ jobs:
             --github-output
 
       - name: Publish verified candidate
-        if: steps.candidate.outputs.has_changes == 'true'
+        if: >-
+          github.event_name != 'pull_request' &&
+          steps.candidate.outputs.has_changes == 'true'
         run: git push --force-with-lease origin HEAD:refs/heads/nightly-candidate
 
   build_macos:
     name: Build macOS arm64
     needs: prepare
-    if: needs.prepare.outputs.has_changes == 'true'
+    if: >-
+      github.event_name != 'pull_request' &&
+      needs.prepare.outputs.has_changes == 'true'
     runs-on: macos-15
     timeout-minutes: 45
     steps:
@@ -248,7 +256,10 @@ jobs:
   release:
     name: Publish GitHub prerelease
     needs: [prepare, build_macos]
-    if: needs.prepare.outputs.has_changes == 'true' && needs.build_macos.result == 'success'
+    if: >-
+      github.event_name != 'pull_request' &&
+      needs.prepare.outputs.has_changes == 'true' &&
+      needs.build_macos.result == 'success'
     runs-on: ubuntu-24.04
     timeout-minutes: 10
     steps:
@@ -306,6 +317,7 @@ jobs:
     needs: [prepare, build_macos, release]
     if: >-
       ${{
+        github.event_name != 'pull_request' &&
         always() &&
         (
           needs.prepare.result == 'failure' ||