improve-quality-job pr comment

.github/workflows/process.yml

@@ -117,6 +117,8 @@ jobs:
         uses: Fusion-Power-Plant-Framework/fppf-actions/hatch-lint@c6af22fc8d00be67cca53a61177301462f499fb2
 
   improve_quality_check:
+    permissions:
+      pull-requests: write
     runs-on: ubuntu-latest
     if: github.event_name == 'pull_request'
     needs: [pre-commit-quality-check]
@@ -147,13 +149,81 @@ jobs:
 
       - name: Run improvement lint
         if: steps.changes.outputs.files != ''
+        id: improvement-lint
         shell: bash
         run: |
-          set -euo pipefail
+          set -uo pipefail
 
           mapfile -t files <<< "${{ steps.changes.outputs.files }}"
 
-          hatch run lint:fmt_extra "${files[@]}"
+          set +e
+          lint_output=$(hatch run lint:fmt_extra "${files[@]}" 2>&1)
+          lint_status=$?
+          set -e
+
+          printf '%s\n' "$lint_output"
+
+          num_pr_errors=$(
+            printf '%s\n' "$lint_output" |
+              grep -oE '[0-9]+' |
+              tail -n 1 ||
+              true
+          )
+
+          num_pr_errors=${num_pr_errors:-0}
+          echo "num_pr_errors=$num_pr_errors" >> "$GITHUB_OUTPUT"
+          echo "PR lint error count: $num_pr_errors"
+
+          exit "$lint_status"
+
+      - name: Get information about the current run
+        if: failure()
+        uses: Fusion-Power-Plant-Framework/fppf-actions/get-workflow-origin@f94a8de5f658cf65c79e1f143a7a31fb94a05793
+        id: workflow-run-info
+      - name: Checkout and lint on main
+        # check out main
+        if: failure() && steps.workflow-run-info.outputs.pullRequestNumber != ''
+        uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
+        with:
+          ref: ${{ steps.workflow-run-info.outputs.targetBranch }}
+      - name: Numbers of errors
+        # want to compare number of errors on main, to see if this PR is introducing more
+        if: failure()
+        run: |
+          mapfile -t files <<< "${{ steps.changes.outputs.files }}"
+          num_main_errors=$((hatch run lint:fmt_extra "${files[@]}" | tail -1) | tr -dc '0-9')
+          num_main_errors=${num_main_errors:-0}
+
+          echo $num_main_errors
+
+          echo compared_errors=$(( ${{ steps.improvement-lint.outputs.num_pr_errors }} - $num_main_errors )) >> $GITHUB_OUTPUT
+          # echo $compared_errors
+        id: num-errors
+
+      - name: Find warning report comment
+        if: failure() && steps.num-errors.outputs.compared_errors > 0
+        uses: peter-evans/find-comment@b30e6a3c0ed37e7c023ccd3f1db5c6c0b0c23aad # v4.0.0
+        id: find-warning-report-comment
+        with:
+          issue-number: ${{ steps.workflow-run-info.outputs.pullRequestNumber }}
+          comment-author: "github-actions[bot]"
+          body-includes: ⚠️ improve_quality_job warning!
+          direction: last
+
+      - name: Warning comment
+        if: failure() && steps.num-errors.outputs.compared_errors > 0
+        uses: peter-evans/create-or-update-comment@e8674b075228eee787fea43ef493e45ece1004c9 # v5.0.0
+        with:
+          comment-id: ${{ steps.find-warning-report-comment.outputs.comment-id }}
+          issue-number: ${{ steps.workflow-run-info.outputs.pullRequestNumber }}
+          body: |
+            ## ⚠️ improve_quality_job warning!
+            Files changed by this PR have introduced **${{steps.num-errors.outputs.compared_errors}} more linting errors** when compared to main
+
+            Please fix these
+
+            To check what these are, run `hatch run lint:fmt_extra` on your branch and on main
+          edit-mode: replace
 
 
   tracking: