screenshot comparison: fix upload for macOS... again (#15914)

# Objective

- Used the wrong variable to set metadata
- new fixes after https://github.com/bevyengine/bevy/pull/15911

## Solution

- Use the right one
- Also keep a reference to the original PR when there's one

.github/workflows/ci-comment-failures.yml

@@ -182,6 +182,8 @@ jobs:
   make-macos-screenshots-available:
     runs-on: ubuntu-latest
     timeout-minutes: 30
+    outputs:
+      branch-name: ${{ steps.branch-name.outputs.result }}
     steps:
       - name: 'Download artifact'
         id: find-artifact
@@ -218,15 +220,22 @@ jobs:
         with:
           name: screenshots-macos
           path: screenshots
-
+      - name: branch name
+        id: branch-name
+        run: |
+          if [ -f PR ]; then
+            echo "result=PR-$(cat PR)-${{ github.event.workflow_run.head_branch }}" >> $GITHUB_OUTPUT
+          else
+            echo "result=${{ github.event.workflow_run.head_branch }}" >> $GITHUB_OUTPUT
+          fi
 
   compare-macos-screenshots:
     name: Compare macOS screenshots
     needs: [make-macos-screenshots-available]
     uses: ./.github/workflows/send-screenshots-to-pixeleagle.yml
     with:
-      commit: ${{ github.event.workflow_run.head_commit }}
-      branch: ${{ github.event.workflow_run.head_branch }}
+      commit: ${{ github.event.workflow_run.head_sha }}
+      branch: ${{ needs.make-macos-screenshots-available.outputs.branch-name }}
       artifact: screenshots-macos
       os: macos
     secrets: inherit

.github/workflows/ci.yml

@@ -287,6 +287,10 @@ jobs:
         with:
           name: example-traces-macos
           path: traces
+      - name: Save PR number
+        if: ${{ github.event_name == 'pull_request' }}
+        run: |
+          echo ${{ github.event.number }} > ./screenshots/PR
       - name: save screenshots
         uses: actions/upload-artifact@v4
         with:

.github/workflows/send-screenshots-to-pixeleagle.yml

@@ -78,17 +78,17 @@ jobs:
           missing=`cat pixeleagle.json | jq '.missing | length'`
           if [ ! $missing -eq 0 ]; then
             echo "There are $missing missing screenshots"
-            echo "::warning title=$missing missing screenshots on ${{ inputs.os }}::https://pixel-eagle.vleue.com/$project/runs/$run/compare/$to"
+            echo "::warning title=$missing missing screenshots on ${{ inputs.os }}::https://pixel-eagle.vleue.com/$project/runs/$run/compare/$compared_with"
             status=1
           fi
 
           diff=`cat pixeleagle.json | jq '.diff | length'`
           if [ ! $diff -eq 0 ]; then
             echo "There are $diff screenshots with a difference"
-            echo "::warning title=$diff different screenshots on ${{ inputs.os }}::https://pixel-eagle.vleue.com/$project/runs/$run/compare/$to"
+            echo "::warning title=$diff different screenshots on ${{ inputs.os }}::https://pixel-eagle.vleue.com/$project/runs/$run/compare/$compared_with"
             status=1
           fi
 
-          echo "created run $run: https://pixel-eagle.vleue.com/$project/runs/$run/compare/$to"
+          echo "created run $run: https://pixel-eagle.vleue.com/$project/runs/$run/compare/$compared_with"
 
           exit $status