ci: use path hashing for pr image tags

Author: InDieTasten

.github/workflows/continuous-integration.yml

@@ -248,13 +248,30 @@ jobs:
         github.event_name == 'pull_request' ||
         ((github.event_name == 'push' || github.event_name == 'schedule') && needs.retag-and-push.outputs.image-exists == 'false')
       )
-    uses: ./.github/workflows/routine-buildimage.yml
-    permissions:
-      packages: write
-    with:
-      tag: ${{ github.event_name == 'pull_request' && format('pr-{0}', github.event.number) || 'latest' }}
-      cr-namespace-repository: ${{ vars.CR_NAMESPACE_REPOSITORY }}
-    secrets: inherit
+    runs-on: ubuntu-latest
+    
+    outputs:
+      image-tag: ${{ steps.generate-tag.outputs.tag }}
+    
+    steps:
+      - uses: actions/checkout@v4
+        
+      - name: Generate content-based image tag
+        id: generate-tag
+        run: |
+            hash=$(find src build scripts -type f -exec sha256sum {} \; | sort | sha256sum | awk '{print $1}')
+            if [ '${{ github.event_name }}' = 'pull_request' ]; then
+              echo "tag=pr-${{ github.event.number }}-${hash:0:8}" >> $GITHUB_OUTPUT
+            else
+              echo "tag=latest" >> $GITHUB_OUTPUT
+            fi
+      
+      - name: Call build workflow
+        uses: ./.github/workflows/routine-buildimage.yml
+        with:
+          tag: ${{ steps.generate-tag.outputs.tag }}
+          cr-namespace-repository: ${{ vars.CR_NAMESPACE_REPOSITORY }}
+        secrets: inherit
 
   deploy-to-environment:
     needs: [check-recording-bot-changes, chart-version-checks, start-cluster, build-docker-image, retag-and-push]
@@ -291,7 +308,7 @@ jobs:
     uses: ./.github/workflows/routine-runtests.yml
     with:
       headless-mode: true
-      test-environment: ${{ github.event_name == 'pull_request' && format('pr-{0}', github.event.number) || 'latest' }}
+      test-environment: ${{ needs.build-docker-image.outputs.image-tag || 'latest' }}
       github-issue-number: ${{ github.event.number || '' }}
     secrets:
       USER_A_USERNAME: ${{ vars.TEST_USER_A_USERNAME }}