fix: fetch live assignees before removal; isolate concurrency per reviewer

- In removeReviewerFromAssignees, replace the stale event-payload
  assignee snapshot with a live pulls.get call so a concurrent
  review_requested run that adds the assignee after the event fires
  does not cause the reviewer to remain assigned permanently
- Give pull_request_review runs a reviewer-scoped concurrency key
  (reviewer-removal-{PR}-{login}) so concurrent review submissions
  from different reviewers are not cancelled by each other
- Update removal-flow tests to populate state.currentPrData.assignees
  so the mock pulls.get returns the correct live assignee list; fix
  error-path mocks to return { data: { assignees: [...] } }

Signed-off-by: Mounil Kanakhara <mounilkankhara@gmail.com>

Author: Mounil2005

.github/scripts/__tests__/jest/bot-pr-add-reviewers-as-assignees.test.js

@@ -251,6 +251,7 @@ describe('Bot: Add Reviewers as Assignees', () => {
 
   test('removes reviewer from assignees when they submit a review', async () => {
     const state = createTestState();
+    state.currentPrData = { assignees: [{ login: 'alice' }, { login: 'bob' }] };
     const ctx = createMockReviewContext({
       reviewerLogin: 'alice',
       assignees: [{ login: 'alice' }, { login: 'bob' }]
@@ -265,6 +266,7 @@ describe('Bot: Add Reviewers as Assignees', () => {
 
   test('does not call removeAssignees when reviewer is not an assignee', async () => {
     const state = createTestState();
+    state.currentPrData = { assignees: [{ login: 'alice' }] };
     const ctx = createMockReviewContext({
       reviewerLogin: 'carol',
       assignees: [{ login: 'alice' }]
@@ -278,6 +280,7 @@ describe('Bot: Add Reviewers as Assignees', () => {
 
   test('review submitted by someone who was never a reviewer is a no-op', async () => {
     const state = createTestState();
+    state.currentPrData = { assignees: [] };
     const ctx = createMockReviewContext({
       reviewerLogin: 'outsider',
       assignees: []
@@ -296,7 +299,7 @@ describe('Bot: Add Reviewers as Assignees', () => {
 
     const errorMock = {
       rest: {
-        pulls: { get: async () => ({}) },
+        pulls: { get: async () => ({ data: { assignees: [{ login: 'alice' }] } }) },
         issues: {
           addAssignees: async () => {},
           removeAssignees: async () => {
@@ -319,7 +322,7 @@ describe('Bot: Add Reviewers as Assignees', () => {
 
     const errorMock = {
       rest: {
-        pulls: { get: async () => ({}) },
+        pulls: { get: async () => ({ data: { assignees: [{ login: 'alice' }] } }) },
         issues: {
           addAssignees: async () => {},
           removeAssignees: async () => {

.github/scripts/bot-pr-add-reviewers-as-assignees.js

@@ -145,7 +145,11 @@ async function removeReviewerFromAssignees({ github, context }) {
 
     const owner = context.repo.owner;
     const repo = context.repo.repo;
-    const currentAssignees = (pr.assignees || []).map(a => a.login);
+
+    // Fetch live PR data rather than relying on the event payload snapshot,
+    // which may be stale if review_requested ran concurrently and added the assignee after this event fired.
+    const livePr = (await github.rest.pulls.get({ owner, repo, pull_number: prNumber })).data;
+    const currentAssignees = (livePr.assignees || []).map(a => a.login);
 
     if (!currentAssignees.includes(reviewer)) {
       logger.log(`${reviewer} is not an assignee on PR #${prNumber}. Nothing to remove.`);