Add option to update the PR comment instead of creating a new one

Author: oacik

README.md

@@ -18,6 +18,7 @@ For more information on these inputs, see the [Workflow syntax for GitHub Action
 - `github-token`: Set the `${{ secrets.GITHUB_TOKEN }}` token to have the action comment the coverage summary in the pull request. This token is provided by Actions, you do not need to create your own token. Optional. Default: ``
 - `working-directory`: The working directory containing the source files referenced in the LCOV files. Optional. Default: `./`
 - `title-prefix`: A prefix before the title "LCOV of commit..." Optional. Default: ``
+- `update-comment`: Set to `true` to update previous code coverage comment if such exists. When set to `false` new comment is always created. Optional. Default: `false`
 
 ### Outputs
 - `total-coverage`: The total coverage from scanned files.
@@ -51,6 +52,7 @@ jobs:
         artifact-name: code-coverage-report
         github-token: ${{ secrets.GITHUB_TOKEN }}
         working-directory: apps/my-first-app
+        update-comment: true
 ```
 *Note:* Only the `pull_request` and `pull_request_target` events are supported. This action does nothing when triggered by other event types.
 

action.yml

@@ -19,6 +19,10 @@ inputs:
   title-prefix:
     description: 'A prefix before the title "LCOV of commit..." Optional. Default: ``'
     required: false
+  update-comment:
+    description: 'Update the existing comment if it exists instead of creating a new one'
+    required: false
+    default: "false"
 outputs:
   total-coverage:
       description: 'The total coverage from scanned files.'

dist/main/index.js

@@ -16,6 +16,7 @@ async function run() {
     const globber = await glob.create(coverageFilesPattern);
     const coverageFiles = await globber.glob();
     const titlePrefix = core.getInput('title-prefix');
+    const updateComment = core.getInput('update-comment');
 
     await genhtml(coverageFiles, tmpPath);
 
@@ -24,42 +25,75 @@ async function run() {
     const minimumCoverage = core.getInput('minimum-coverage');
     const gitHubToken = core.getInput('github-token').trim();
     const errorMessage = `The code coverage is too low: ${totalCoverage}. Expected at least ${minimumCoverage}.`;
-    const isFailure = totalCoverage < minimumCoverage;
+    const isMinimumCoverageReached = totalCoverage >= minimumCoverage;
 
     if (gitHubToken !== '' && events.includes(github.context.eventName)) {
       const octokit = await github.getOctokit(gitHubToken);
       const summary = await summarize(coverageFile);
       const details = await detail(coverageFile, octokit);
       const sha = github.context.payload.pull_request.head.sha;
       const shaShort = sha.substr(0, 7);
-      let body = `### ${titlePrefix ? `${titlePrefix} ` : ''}[LCOV](https://github.com/marketplace/actions/report-lcov) of commit [<code>${shaShort}</code>](${github.context.payload.pull_request.number}/commits/${sha}) during [${github.context.workflow} #${github.context.runNumber}](../actions/runs/${github.context.runId})\n<pre>${summary}\n\nFiles changed coverage rate:${details}</pre>`;
+      const commentHeaderPrefix = `### ${titlePrefix ? `${titlePrefix} ` : ''}[LCOV](https://github.com/marketplace/actions/report-lcov) of commit`;
+      let body = `${commentHeaderPrefix} [<code>${shaShort}</code>](${github.context.payload.pull_request.number}/commits/${sha}) during [${github.context.workflow} #${github.context.runNumber}](../actions/runs/${github.context.runId})\n<pre>${summary}\n\nFiles changed coverage rate:${details}</pre>`;
 
-      if (isFailure) {
+      if (!isMinimumCoverageReached) {
         body += `\n:no_entry: ${errorMessage}`;
       }
 
-      core.debug("Creating a comment in the PR.")
-      await octokit.issues.createComment({
-        owner: github.context.repo.owner,
-        repo: github.context.repo.repo,
-        issue_number: github.context.payload.pull_request.number,
-        body: body,
-      });
+      updateComment === "true" ? await upsertComment(body, commentHeaderPrefix, octokit) : await createNewComment(body, octokit);
     } else {
       core.info("github-token received is empty. Skipping writing a comment in the PR.");
       core.info("Note: This could happen even if github-token was provided in workflow file. It could be because your github token does not have permissions for commenting in target repo.")
     }
 
     core.setOutput("total-coverage", totalCoverage);
 
-    if (isFailure) {
+    if (!isMinimumCoverageReached) {
       throw Error(errorMessage);
     }
   } catch (error) {
     core.setFailed(error.message);
   }
 }
 
+async function createNewComment(body, octokit) {
+  core.debug("Creating a comment in the PR.")
+
+  await octokit.issues.createComment({
+    repo: github.context.repo.repo,
+    owner: github.context.repo.owner,
+    issue_number: github.context.payload.pull_request.number,
+    body,
+  });
+}
+
+async function upsertComment(body, commentHeaderPrefix, octokit) {
+  const issueComments = await octokit.issues.listComments({
+    repo: github.context.repo.repo,
+    owner: github.context.repo.owner,
+    issue_number: github.context.payload.pull_request.number,
+  });
+
+  const existingComment = issueComments.data.find(comment =>
+    comment.body.includes(commentHeaderPrefix),
+  );
+
+  if (existingComment) {
+    core.debug(`Updating comment, id: ${existingComment.id}.`);
+
+    await octokit.issues.updateComment({
+      repo: github.context.repo.repo,
+      owner: github.context.repo.owner,
+      comment_id: existingComment.id,
+      body,
+    });
+  } else {
+    core.debug(`Comment does not exist, new comment will be created.`);
+
+    await createNewComment(body, octokit);
+  }
+}
+
 async function genhtml(coverageFiles, tmpPath) {
   const workingDirectory = core.getInput('working-directory').trim() || './';
   const artifactName = core.getInput('artifact-name').trim();