ci: verify changes to Maintainers.yaml made by the bot

.github/workflows/verify-maintainers.yaml

@@ -0,0 +1,98 @@
+name: Verify if human changes in PR are allowed
+
+on:
+  pull_request:
+    types: [synchronize, opened]
+    paths:
+      - "MAINTAINERS.yaml"
+
+jobs:
+  verify-changes:
+    # if statement to check if the PR is open.
+    if: github.event.pull_request.state == 'open'
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout main branch
+        uses: actions/checkout@v3
+        with:
+          ref: master
+          path: community-main
+
+      - name: Checkout PR branch
+        uses: actions/checkout@v3
+        with:
+          ref: ${{ github.head_ref }}
+          path: pr-branch
+
+      - name: Install Dependencies
+        run: npm install yaml
+
+      - name: Verify changes in MAINTAINERS.yaml
+        id: verify-changes
+        uses: actions/github-script@v5
+        with:
+          github-token: ${{ secrets.GITHUB_TOKEN }}
+          script: |
+            const yaml = require("yaml");
+            const fs = require("fs");
+
+            const mainFile = yaml.parse(fs.readFileSync("./community-main/MAINTAINERS.yaml", "utf8"));
+            const prFile = yaml.parse(fs.readFileSync("./pr-branch/MAINTAINERS.yaml", "utf8"));
+
+            const beforeMaintainers = new Map(mainFile.map((maintainer) => [maintainer.name, {github: maintainer.github, repos: maintainer.repos || []}]));
+            let errorMessages = [];
+
+            const owner = context.repo.owner;
+            const repo = context.repo.repo;
+            const pull_number = context.issue.number;
+            const author = context.payload.pull_request.user.login;
+
+            // If the PR is made by the bot, don't do anything.
+            if (author === 'asyncapi-bot') {
+              console.log('Changes made by asyncapi-bot, skipping verification.');
+              return;
+            }
+
+            // detecting if changes in the PR contain removal of maintainer object 
+            if (prFile.length < mainFile.length) {
+              errorMessages.push('A maintainer has been removed from `MAINTAINERS.yaml` file. Only `asyncapi-bot` can make such changes. Maintainers are removed from the file in an automated way only if they are no longer mentioned in `CODEOWNERS` file in any repository under AsyncAPI GitHub organization.');
+            }
+
+            for (const maintainer of prFile) {
+              // retrieve the previous data of the maintainer from the main file
+              const previousData = beforeMaintainers.get(maintainer.name);
+              // if the maintainer is not found in the previous data, it is a new maintainer 
+              if (!previousData) {
+                errorMessages.push(`A new maintainer, ${maintainer.name}, has been added to MAINTAINERS.yaml. Only asyncapi-bot can make such changes. Maintainers are added to the file in an automated way only if they are mentioned in the CODEOWNERS file in any repository under AsyncAPI GitHub organization.`);
+              } else {
+                // retrieve the previous GitHub key and repositories of the maintainer
+                const previousGithub = previousData.github;
+                const previousRepos = previousData.repos;
+                // check if the GitHub key for the maintainer has been modified
+                if (previousGithub !== maintainer.github) {
+                  errorMessages.push(`GitHub key for ${maintainer.name} has been modified in MAINTAINERS.yaml. Only asyncapi-bot can make such changes. This information is derived from the CODEOWNERS file located in any repository under AsyncAPI GitHub organization.`);
+                }
+                // check if the repositories list for the maintainer has been modified
+                if (previousRepos.toString() !== (maintainer.repos || []).toString()) {
+                  // Check if a human added a repo to the maintainer's repository list
+                  const previousReposLength = previousData.repos.length;
+                  const currentReposLength = (maintainer.repos || []).length;
+                  if (currentReposLength > previousReposLength) {
+                    const addedRepos = (maintainer.repos || []).slice(previousReposLength);
+                    errorMessages.push(`New repositories (${addedRepos.join(', ')}) have been added to ${maintainer.name}'s repository list in MAINTAINERS.yaml. Only asyncapi-bot can make such changes. This information is derived from the CODEOWNERS file located in any repository under AsyncAPI GitHub organization.`);
+                  }
+                }
+              }
+            }
+
+            // If there are any error messages, create a comment on the PR and close it
+            if (errorMessages.length > 0) {
+              const commentBody = errorMessages.join('\n');
+              github.rest.issues.createComment({ owner, repo, issue_number: pull_number, body: commentBody });
+              github.rest.pulls.update({
+                owner,
+                repo,
+                pull_number,
+                state: 'closed'
+              });
+            }