fix: handle dismissed review state

Author: aeddi

contribs/github-bot/internal/requirements/reviewer.go

@@ -36,10 +36,21 @@ func deduplicateReviews(reviews []*github.PullRequestReview) []*github.PullReque
 				result = append(result, rev)
 				added[rev.User.GetLogin()] = len(result) - 1
 			}
+		case utils.ReviewStateDismissed:
+			// this state just dismisses any previous review, so remove previous
+			// entry for this user if it exists.
+			if ok {
+				result[idx] = nil
+			}
 		default:
 			panic(fmt.Sprintf("invalid review state %q", rev.GetState()))
 		}
 	}
+	// Remove nil entries from the result (dismissed reviews).
+	result = slices.DeleteFunc(result, func(r *github.PullRequestReview) bool {
+		return r == nil
+	})
+
 	return result
 }
 

contribs/github-bot/internal/requirements/reviewer_test.go

@@ -68,6 +68,16 @@ func Test_deduplicateReviews(t *testing.T) {
 				{User: &github.User{Login: github.String("userB")}, State: github.String("CHANGES_REQUESTED")},
 			},
 		},
+		{
+			name: "two authors - approval/changes requested then dismissed",
+			reviews: []*github.PullRequestReview{
+				{User: &github.User{Login: github.String("user1")}, State: github.String("APPROVED")},
+				{User: &github.User{Login: github.String("user1")}, State: github.String("DISMISSED")},
+				{User: &github.User{Login: github.String("user2")}, State: github.String("CHANGES_REQUESTED")},
+				{User: &github.User{Login: github.String("user2")}, State: github.String("DISMISSED")},
+			},
+			expected: []*github.PullRequestReview{},
+		},
 	}
 
 	for _, tt := range tests {

contribs/github-bot/internal/utils/github_const.go

@@ -23,6 +23,7 @@ const (
 	ReviewStateApproved         ReviewState = "APPROVED"
 	ReviewStateChangesRequested ReviewState = "CHANGES_REQUESTED"
 	ReviewStateCommented        ReviewState = "COMMENTED"
+	ReviewStateDismissed        ReviewState = "DISMISSED"
 )
 
 // Valid determines whether the ReviewState is one of the known ReviewStates.