added action validation (#40)

I had many times the problem of setting the action to point to its own
branch to test, only to forget about setting it again to the main
branch.

This adds a check that makes the PR fails unless that the branch is
actually pointing to main.

.github/workflows/publish.yml

@@ -15,5 +15,24 @@ jobs:
       - uses: actions/[email protected]
       - name: Check that the image builds
         run: docker build . --file Dockerfile
+  validate-action:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/[email protected]
+      # This checks that .github/workflows/review-bot.yml is pointing towards the main branch
+      # as, during development, we change this to use the code from the test branch and
+      # we may forget to set it back to main
+      - name: Validate that action points to main branch
+        run: |
+          BRANCH=$(yq '.jobs.review-approvals.steps[0].uses' $FILE_NAME | cut -d "@" -f2)
+          # If the branch is not the main branch
+          if [ "$BRANCH" != "$GITHUB_BASE_REF" ]; then
+            echo "Action points to $BRANCH. It has to point to $GITHUB_BASE_REF instead!"
+            exit 1
+          else
+            echo "Action is correctly pointing to $GITHUB_BASE_REF"
+          fi
+        env:
+          FILE_NAME: ".github/workflows/review-bot.yml"
 
 # Todo: Add the rest of the action https://github.com/paritytech/stale-pr-finder/blob/main/.github/workflows/publish.yml

.github/workflows/review-bot.yml

@@ -17,7 +17,8 @@ jobs:
   review-approvals:
     runs-on: ubuntu-latest
     steps:
-      # TODO: Set this to main
+      # !This must always point to main. 
+      # Change it for the PRs but remember to change it back
       - uses: paritytech/review-bot@main
         with:
           repo-token: ${{ secrets.GITHUB_TOKEN }}