Merge branch 'master' into fix-buildcache

.github/workflows/ci.yaml

@@ -108,9 +108,19 @@ jobs:
       - id: ref
         name: Format docker tag and repository name for current image.
         run: |-
-          # This will take a ref like `refs/heads/master`
-          # and turn it into `refs-heads-master`
-          REF_ID=$(echo $GITHUB_REF | sed 's/\//-/g')
+
+          if [ "${{ github.event_name }}" = "pull_request_target" ]; then
+            # Construct the PR_GITHUB_REF for our pull request copying GITHUB_REF's format
+            # We can't use GITHUB_REF because it is set to master in this event
+            # More info: https://docs.github.com/en/actions/using-workflows/events-that-trigger-workflows#pull_request_target
+            PR_GITHUB_REF="refs/pull/${{ github.event.pull_request.number }}/merge"
+            REF_ID=$(echo $PR_GITHUB_REF | sed 's/\//-/g')
+          else
+            # This will take a ref like `refs/heads/master`
+            # and turn it into `refs-heads-master`
+            REF_ID=$(echo $GITHUB_REF | sed 's/\//-/g')
+          fi
+
           echo "ref-id=$REF_ID" >> $GITHUB_OUTPUT
 
           # the final tag is something like:
@@ -120,7 +130,7 @@ jobs:
 
           # In push & PR events we want the tag to contain the latest commit on the branch:
           # in push events, the latest commit of the master branch is GITHUB_SHA
-          # in PR synch the latest commit of the branch is found in github.event.pull_request.head.sha instead
+          # in PR synch the latest commit of the branch is found in github.sha instead
 
           TIMESTAMP=$(date +%s)
 
@@ -130,7 +140,7 @@ jobs:
             TIMESTAMP=""
             BATCH_IMAGE_TAG=production
           elif [ "${{ github.event_name }}" = "pull_request_target" ]; then
-            COMMIT_SHA="${{ github.event.pull_request.head.sha }}"
+            COMMIT_SHA="${{ github.sha }}"
             IMAGE_TAG="$REF_ID-$COMMIT_SHA"
             TIMESTAMP=$TIMESTAMP
             BATCH_IMAGE_TAG=$REF_ID