Update main.yml

Author: BrianCollinss

.github/workflows/main.yml

@@ -1,9 +1,8 @@
-name: Merge Master into AAA_ForSesame and Push
+name: Merge ApsimX Master into AAA_ForSesame and Push
 
 on:
-  push:
-    branches:
-      - master
+  schedule:
+    - cron: '0 */4 * * *' # Run every 4 hours (adjust as needed)
 
 jobs:
   merge_and_push:
@@ -22,14 +21,28 @@ jobs:
           ref: AAA_ForSesame
           path: ApsimNG 
 
-      - name: Merge Master into AAA_ForSesame
+      - name: Check for changes in ApsimX master
+        id: check_changes
+        run: |
+          cd ApsimNG
+          git remote add apsimx https://github.com/APSIMInitiative/ApsimX.git
+          git fetch apsimx master
+          if [ $(git rev-list --count apsimx/master..AAA_ForSesame) -gt 0 ]; then
+            echo "changes_exist=true" >> $GITHUB_OUTPUT
+          else
+            echo "changes_exist=false" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Merge Master into AAA_ForSesame (if changes exist)
+        if: steps.check_changes.outputs.changes_exist == 'true'
         run: |
           cd ApsimNG
           git config --global user.name 'GitHub Action'
           git config --global user.email 'action@github.com'
           git merge origin/master
 
-      - name: Push AAA_ForSesame to ApsimNG
+      - name: Push AAA_ForSesame to ApsimNG (if changes exist)
+        if: steps.check_changes.outputs.changes_exist == 'true'
         run: |
           cd ApsimNG
           git push