.github/workflows/config-diff-post-comment.js: improve handling of GH comment

1. When no configuration changes are detected, delete the outdated
   configuration diff Github comment. This ensures that the PR does not
   have any misleading information about configuration changes.
2. Configuration changes might change with every push event, update the
   old configuration diff comment with the new configDiff that was
   calculated in the present run.

Signed-off-by: Naveen Naidu <[email protected]>

Author: Naveenaidu

.github/workflows/scripts/config-diff-post-comment.js

@@ -1,11 +1,37 @@
 module.exports = async ({ github, context, core, configDiff }) => {
   try {
-      // Do not create comment if there are no configuration changes
-      if (!configDiff) {
-        console.log("No changes detected. Skipping comment creation.");
-        return;
+    const { owner, repo } = context.repo;
+    const issueNumber = context.payload.pull_request.number;
+
+    // List all the comments
+    const comments = await github.paginate(
+      github.rest.issues.listComments, {
+        owner,
+        repo,
+        issue_number: issueNumber,
+        per_page: 100,
+      }
+    );
+
+    const existingComment = comments.find(comment => comment.body.includes("### Config Diff Tool Output"));
+
+    // Do not create comment if there are no configuration changes
+    if (!configDiff) {
+      core.info("No changes detected. Skipping comment creation.");
+
+      if (existingComment){
+        // Remove any outdated configuration diff comments
+        core.info("Existing config diff comment found. Deleting it...");
+        await github.rest.issues.deleteComment({
+            comment_id: existingComment.id,
+            owner,
+            repo,
+        });
       }
 
+      return;
+    }
+
       const commentBody = `
 ### Config Diff Tool Output
 
@@ -19,21 +45,15 @@ ${configDiff}
 The above configuration changes are found in the PR. Please update the relevant release documentation if necessary.
   `;
 
-      core.summary.addRaw(commentBody);
-      await core.summary.write()
-
-      const { owner, repo } = context.repo;
-      const issueNumber = context.payload.pull_request.number;
-
       // List all files in the pull request
       core.info("Fetching list of files changed in the pull request...");
       const files = await github.paginate(
           github.rest.pulls.listFiles,
           {
-              owner,
-              repo,
-              pull_number: issueNumber,
-              per_page: 100,
+            owner,
+            repo,
+            pull_number: issueNumber,
+            per_page: 100,
           }
       );
 
@@ -42,33 +62,35 @@ The above configuration changes are found in the PR. Please update the relevant
         // Only annotate the `yaml.in` files present in `src/common/options` folder
         if (file.filename.endsWith(".yaml.in") && file.filename.startsWith("src/common/options/")) {
             core.info(`Annotating file: ${file.filename}`);
+            // Show annotations only at the start of the file
             core.notice(
-                `Configuration changes detected in ${file.filename}. Please update the relevant release documentation if necessary.`,
+                `Configuration changes detected in ${file.filename}. Please update the release documentation if necessary.`,
                 {
-                    title: "Configuration Change Detected",
-                    file: file.filename,
-                    startLine: 1,
-                    endLine: 1,
+                  title: "Configuration Change Detected",
+                  file: file.filename,
+                  startLine: 1,
+                  endLine: 1,
                 }
             );
         }
-    });
+      });
 
-      
-      // List all the comments
-      const comments = await github.paginate(
-        github.rest.issues.listComments, {
+      core.summary.addRaw(commentBody);
+      await core.summary.write()
+
+      if (existingComment) {
+        // There might have been new configuration changes made after posting
+        // the first comment. Hence replace the old comment with the new updated
+        // changes
+        core.info("A config diff comment already exists, updating it...");
+
+        // Update the existing comment
+        await github.rest.issues.updateComment ({
+          comment_id: existingComment.id,
           owner,
           repo,
-          issue_number: issueNumber,
-          per_page: 100,
-        }
-      );
-  
-      const existingComment = comments.find(comment => comment.body.includes("### Config Diff Tool Output"));
-  
-      if (existingComment) {
-        core.info("A config diff comment already exists, deleting it...");
+          body: commentBody,
+        });
       } else {
         core.info("Creating a new config diff comment...");
         // Create a new comment
@@ -80,7 +102,7 @@ The above configuration changes are found in the PR. Please update the relevant
         });
 
       }
-  
+
       // Set the status as FAILED if any configuration changes are detected
       core.setFailed("Configuration Changes Detected, Update release documents - if necessary");
     } catch (error) {