ci: seeing if we can avoid rebuilding everythign on push

.forgejo/workflows/push.yaml

@@ -14,10 +14,40 @@ on:
   workflow_dispatch:
 
 jobs:
+  changes:
+    runs-on: nix
+    # Required permissions
+    permissions:
+      pull-requests: read
+    # Set job outputs to values from filter step
+    outputs:
+      forgejo: ${{ steps.filter.outputs.forgejo }}
+      minutes: ${{ steps.filter.outputs.minutes }}
+      events: ${{ steps.filter.outputs.events }}
+      handovers: ${{ steps.filter.outputs.handovers }}
+      budget: ${{ steps.filter.outputs.budgets  }}
+    steps:
+      # For pull requests it's not necessary to checkout the code
+      - uses: https://github.com/dorny/paths-filter@v3
+        id: filter
+        with:
+          filters: |
+            forgejo:
+              - '.forgejo/**/*'
+            minutes:
+              - 'Minutes/**/*'
+            events:
+              - 'Events/**/*'
+            handovers:
+              - 'Committee/**/Handovers/*'
+            budgets:
+              - 'Committee/**/Budget/*'
+
   # rust code must be formatted for standardisation
   pdfs:
     # build it using teh base nixos system, helps with caching
     runs-on: nix
+    needs: changes
     strategy:
       matrix:
         script: [ handovers, minutes, budget, events ]
@@ -25,20 +55,26 @@ jobs:
       # needs this to create tags and releases
       contents: write
     steps:
+      # the if statements are to only run if there are changes in the sub dir
       # get the repo first
-      - uses: https://code.forgejo.org/actions/checkout@v4
-      - uses: https://forgejo.skynet.ie/Skynet/actions-deploy-to-skynet/get_lfs@v3
+      - if: ${{ needs.changes.outputs.${{ matrix.script }} == 'true' }}
+        uses: https://code.forgejo.org/actions/checkout@v4
+      - if: ${{ needs.changes.outputs.${{ matrix.script }} == 'true' }}
+        uses: https://forgejo.skynet.ie/Skynet/actions-deploy-to-skynet/get_lfs@v3
         with:
           repository: ${{ gitea.repository }}
           ref_name: ${{ gitea.ref_name }}
       # actual script to run the build process
-      - run: nix run .#${{ matrix.script }}
+      - if: ${{ needs.changes.outputs.${{ matrix.script }} == 'true' }}
+        run: nix run .#${{ matrix.script }}
       # zip the files so they can be released
-      - run: |
+      - if: ${{ needs.changes.outputs.${{ matrix.script }} == 'true' }}
+        run: |
           mkdir releases
           zip -r releases/${{ matrix.script }}.zip pdf_${{ matrix.script }}
       # upload them so they are available at https://forgejo.skynet.ie/Computer_Society/open-goverance/releases/tag/minutes_latest
-      - uses: https://forgejo.skynet.ie/Skynet/actions-forgejo-release@v1
+      - if: ${{ needs.changes.outputs.${{ matrix.script }} == 'true' }}
+        uses: https://forgejo.skynet.ie/Skynet/actions-forgejo-release@v1
         with:
           token: ${{ secrets.API_TOKEN_FORGEJO }}
           direction: upload