Show flake8 errors introduced

.github/workflows/lint.yml

@@ -22,28 +22,28 @@ jobs:
         python -m pip install --upgrade pip
         pip install flake8
     - name: Get current errors
-      # echo "CURRENT_ERROR_STR=\"$(cat $tmpafter)\"" >> $GITHUB_ENV
       run: |
         tmpafter=$(mktemp)
         find src -name \*.py -exec flake8 --ignore=E402,E501,W504 {} + | egrep -v "alembic/versions/|usr/local/share/pysnmp/mibs/" > $tmpafter
         num_errors_after=`cat $tmpafter | wc -l`
+        echo "CURRENT_ERROR_FILE=${tmpafter}" >> $GITHUB_ENV
         echo "CURRENT_ERRORS=${num_errors_after}" >> $GITHUB_ENV
     - name: Checkout base branch
       uses: actions/checkout@v2
       with:
         ref: ${{ github.base_ref }}
     - name: Get errors from base branch
-      # echo "OLD_ERROR_STR=\"$(cat $tmpbefore)\"" >> $GITHUB_ENV
       run: |
         tmpbefore=$(mktemp)
         find src -name \*.py -exec flake8 --ignore=E402,E501,W504 {} + | egrep -v "alembic/versions/|usr/local/share/pysnmp/mibs/" > $tmpbefore
         num_errors_before=`cat $tmpbefore | wc -l`
+        echo "OLD_ERROR_FILE=${tmpbefore}" >> $GITHUB_ENV
         echo "OLD_ERRORS=${num_errors_before}" >> $GITHUB_ENV
     - name: Conclusion
-      # diff <(echo "${{ env.OLD_ERROR_STR }}") <(echo "${{ env.CURRENT_ERROR_str }}")
       run: |
         if [ ${{ env.CURRENT_ERRORS }} -gt ${{ env.OLD_ERRORS }} ]; then
           echo "New flake8 errors were introduced"
+          diff -u ${{ env.OLD_ERROR_FILE }} ${{ env.CURRENT_ERROR_FILE }}
           exit 1
         else
           echo "No new flake 8 errors were introduced"