Merge pull request #2 from gitgitgadget-workflows/fix-keepalive-in-forks

Avoid letting forks diverge because of the `keepalive` workflow

Author: dscho

.github/workflows/keepalive.yml

@@ -2,29 +2,50 @@ name: Keep scheduled workflows alive
 
 on:
   schedule:
-    - cron: "23 19 17 * *" # 7:23pm on every 17th of the month
+    - cron: "23 19 3,17 * *" # 7:23pm on every 3rd and 17th of the month
   workflow_dispatch:
 
+env:
+  GIT_CONFIG_PARAMETERS: "'user.name=CI' 'user.email=ci@github'"
+
 jobs:
   job:
     runs-on: ubuntu-latest
-    strategy:
-      fail-fast: false
     permissions:
       contents: write
     steps:
       - uses: actions/checkout@v4
         with:
           persist-credentials: 'true'
-      - name: Create and push a commit
-        env:
-          GIT_CONFIG_PARAMETERS: "'user.name=CI' 'user.email=ci@github'"
+      - name: Merge the upstream default branch
+        id: merge
+        if: github.event.repository.fork == true
+        run: |
+          git fetch https://github.com/gitgitgadget/gitgitgadget-workflows HEAD &&
+          if test 0 = $(git rev-list --count HEAD..FETCH_HEAD)
+          then
+            exit 0 # let the next step create a commit
+          fi &&
+          git merge --no-edit FETCH_HEAD &&
+          echo "result=merged" >>$GITHUB_OUTPUT
+      - name: Create a commit
+        id: commit
+        if: steps.merge.outputs.result != 'merged'
         run: |
+          if test 0 -lt $(git rev-list --count --since=3.weeks.ago HEAD)
+          then
+            echo "::notice::No need to keep alive, there were commits in the last three weeks"
+            echo "result=skip-push" >>$GITHUB_OUTPUT
+            exit 0
+          fi &&
           mkdir -p .github/cached
           file='.github/cached/keepalive.txt'
           date >$file
           git add "$file"
-          git commit -m "workflow keepalive" &&
+          git commit -m "workflow keepalive"
+      - name: Push changes
+        if: steps.commit.outputs.result != 'skip-push'
+        run: |
           git push origin HEAD </dev/null || {
             for i in 1 2 3 4 5
             do