feat: use review comments (#104)

* use pull request reviews, reusing same review with each run

README.md

@@ -43,10 +43,12 @@ This action drives the following outcomes:
 
 Check | Outcome on Failure
 --- | ---
-PR Title Lint | Action shows as failed check. Action leaves comment.
-PR Refers to Issue | Action closes issue. Action leaves comment.
-PR Originates from Protected Branch | Action closes issue. Action leaves comment.
-PR Avoids Watched Files | Action leaves comment.
+PR Title Lint | Action shows as failed check. Action leaves review comment.
+PR Refers to Issue | Action closes issue. Action leaves review comment.
+PR Originates from Protected Branch | Action closes issue. Action leaves review comment.
+PR Avoids Watched Files | Action leaves review comment.
+
+If a PR is initially deemed non-compliant by the action and a review comment is left, the action will update this same review comment each time it runs again (e.g. if the PR title or description changes). If the PR is found to be compliant after changes, the review comment will be updated to reflect this.
 
 ## Inputs
 

src/main.ts

@@ -3,6 +3,18 @@ import * as github from '@actions/github'
 import {context} from '@actions/github/lib/utils'
 import {checkBody, checkTitle, checkBranch} from './checks'
 
+type PullRequestReview = {
+  id: number
+  node_id: string
+  user: {
+    login: string
+    id: number
+    node_id: string
+  } | null
+  body: string
+  state: string
+}
+
 const repoToken = core.getInput('repo-token')
 const ignoreAuthors = core.getMultilineInput('ignore-authors')
 const ignoreTeamMembers = core.getBooleanInput('ignore-team-members')
@@ -121,27 +133,26 @@ async function run(): Promise<void> {
           commentsToLeave.push(watchedFilesComment + filesList)
         }
       }
-      // Finally close PR if warranted
+      // Update Review as needed
+      let reviewBody = ''
       if (commentsToLeave.length > 0)
-        await createComment(
-          pr.number,
-          [baseComment, ...commentsToLeave].join('\n\n')
-        )
+        reviewBody = [baseComment, ...commentsToLeave].join('\n\n')
+      await updateReview(
+        {owner: pr.owner, repo: pr.repo, pull_number: pr.number},
+        reviewBody
+      )
       // Finally close PR if warranted
       if (shouldClosePr) await closePullRequest(pr.number)
+    } else {
+      await updateReview(
+        {owner: pr.owner, repo: pr.repo, pull_number: pr.number},
+        ''
+      )
     }
   } catch (error) {
     if (error instanceof Error) core.setFailed(error.message)
   }
 }
-async function createComment(number: number, comment: string) {
-  if (comment.trim() !== '')
-    await client.rest.issues.createComment({
-      ...context.repo,
-      issue_number: number,
-      body: comment
-    })
-}
 async function closePullRequest(number: number) {
   await client.rest.pulls.update({
     ...context.repo,
@@ -164,6 +175,56 @@ async function listFiles(pullRequest: {
   const {data: files} = await client.rest.pulls.listFiles(pullRequest)
   return files
 }
+async function findExistingReview(pullRequest: {
+  owner: string
+  repo: string
+  pull_number: number
+}): Promise<PullRequestReview | null> {
+  let review
+  const {data: reviews} = await client.rest.pulls.listReviews(pullRequest)
+  review = reviews.find(review => {
+    return (review?.user?.login ?? '') == 'github-actions[bot]'
+  })
+  if (review === undefined) review = null
+  return review
+}
+async function updateReview(
+  pullRequest: {owner: string; repo: string; pull_number: number},
+  body: string
+) {
+  const review = await findExistingReview(pullRequest)
+  // if blank body and no existing review, exit
+  if (body === '' && review === null) return
+  // if review body same as new body, exit
+  if (body === review?.body) return
+  // if no existing review, body non blank, create a review
+  if (review === null && body !== '') {
+    await client.rest.pulls.createReview({
+      ...pullRequest,
+      body,
+      event: 'COMMENT'
+    })
+    return
+  }
+  // if body blank and review exists, update it to show passed
+  if (review !== null && body === '') {
+    await client.rest.pulls.updateReview({
+      ...pullRequest,
+      review_id: review.id,
+      body: 'PR Compliance Checks Passed!'
+    })
+    return
+  }
+  // if body non-blank and review exists, update it
+  if (review !== null && body !== review?.body) {
+    await client.rest.pulls.updateReview({
+      ...pullRequest,
+      review_id: review.id,
+      body
+    })
+    return
+  }
+}
 async function userIsTeamMember(login: string, owner: string) {
   if (login === owner) return true
   const {data: userOrgs} = await client.request('GET /users/{user}/orgs', {