CI: Post output from semver-checks as a comment

Author: Lorak-mmk

.github/workflows/semver_checks.yml

@@ -34,6 +34,7 @@ jobs:
     timeout-minutes: 30
     outputs:
       exitcode: ${{ steps.semver-pr-check.outputs.exitcode }}
+      output: ${{ steps.semver-pr-check.outputs.output }}
     steps:
     - name: Checkout
       uses: actions/checkout@v3
@@ -56,8 +57,11 @@ jobs:
       id: semver-pr-check
       run: |
         set +e
-        make semver-rev rev="$PR_BASE"
-        exitcode=$?
+        echo "output<<SEMVER_STDOUT_EOF" >> $GITHUB_OUTPUT
+        # Weird sed strip ANSI colors from output
+        make semver-rev rev="$PR_BASE" |& tee /dev/tty | sed -r "s/\x1B\[([0-9]{1,2}(;[0-9]{1,2})?)?[mGK]//g" >> $GITHUB_OUTPUT
+        exitcode=${PIPESTATUS[0]}
+        echo "SEMVER_STDOUT_EOF" >> $GITHUB_OUTPUT
         echo "exitcode=$exitcode" >> $GITHUB_OUTPUT
         exit "$exitcode"
       continue-on-error: true
@@ -82,6 +86,26 @@ jobs:
       env:
         GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
         GH_REPO: ${{ github.repository }}
+    - name: Post report on semver break
+      run: |
+        gh pr comment "$PR_ID" --body "\
+        \`cargo semver-checks\` detected some API incompatibilities in this PR.
+        See the following report for details:
+        <details>
+        <summary>cargo semver-checks output</summary>
+
+        \`\`\`
+        $SEMVER_OUTPUT
+        \`\`\`
+
+        </details>
+        "
+      if: needs.semver-pull-request-check.outputs.exitcode != '0'
+      env:
+        GH_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        GH_REPO: ${{ github.repository }}
+        SEMVER_OUTPUT: ${{ needs.semver-pull-request-check.outputs.output }}
+
 
   semver-push-tag:
     runs-on: ubuntu-latest