Wait for the failed message index when restoring deleted messages by range

src/ServiceControl.Persistence.RavenDB/ErrorMessagesDataStore.cs

@@ -429,9 +429,12 @@ public async Task<string[]> UnArchiveMessagesByRange(DateTime from, DateTime to,
                 }
             };
 
+            // The index has to include the latest changes. Otherwise, a message deleted right before the request is not
+            // in the index as archived yet, and the patch leaves it archived without reporting it.
             var patch = new PatchByQueryOperation(query, new QueryOperationOptions
             {
-                AllowStale = true,
+                AllowStale = false,
+                StaleTimeout = TimeSpan.FromMinutes(5),
                 RetrieveDetails = true
             });
 

src/ServiceControl.Persistence.Tests.RavenDB/Unarchiving/UnarchiveByRangeTests.cs

@@ -0,0 +1,67 @@
+namespace ServiceControl.Persistence.Tests.RavenDB.Unarchiving
+{
+    using System;
+    using System.Threading.Tasks;
+    using MessageFailures;
+    using MessageFailures.Api;
+    using NUnit.Framework;
+    using Raven.Client.Documents.Operations.Indexes;
+    using ServiceControl.Persistence;
+
+    [TestFixture]
+    class UnarchiveByRangeTests : RavenPersistenceTestBase
+    {
+        [Test]
+        public async Task Should_unarchive_a_message_archived_right_before_the_request()
+        {
+            var uniqueMessageId = Guid.NewGuid().ToString();
+            var documentId = FailedMessageIdGenerator.MakeDocumentId(uniqueMessageId);
+            var indexName = new FailedMessageViewIndex().IndexName;
+
+            using (var session = DocumentStore.OpenAsyncSession())
+            {
+                await session.StoreAsync(FailedMessageBuilder.Minimal(message =>
+                {
+                    message.Id = documentId;
+                    message.UniqueMessageId = uniqueMessageId;
+                }));
+                await session.SaveChangesAsync();
+            }
+
+            await CompleteDatabaseOperation();
+
+            // The index still has the message as unresolved when the range is unarchived
+            await DocumentStore.Maintenance.SendAsync(new StopIndexOperation(indexName));
+
+            try
+            {
+                using (var session = DocumentStore.OpenAsyncSession())
+                {
+                    var message = await session.LoadAsync<FailedMessage>(documentId);
+                    message.Status = FailedMessageStatus.Archived;
+                    await session.SaveChangesAsync();
+                }
+
+                var unarchive = FailedMessageLifecycleStore.UnArchiveMessagesByRange(DateTime.UtcNow.AddHours(-1), DateTime.UtcNow.AddHours(1));
+
+                await Task.Delay(TimeSpan.FromSeconds(1));
+                await DocumentStore.Maintenance.SendAsync(new StartIndexOperation(indexName));
+
+                var unarchived = await unarchive;
+
+                using var verifySession = DocumentStore.OpenAsyncSession();
+                var unarchivedMessage = await verifySession.LoadAsync<FailedMessage>(documentId);
+
+                using (Assert.EnterMultipleScope())
+                {
+                    Assert.That(unarchived, Is.EquivalentTo(new[] { documentId }));
+                    Assert.That(unarchivedMessage.Status, Is.EqualTo(FailedMessageStatus.Unresolved));
+                }
+            }
+            finally
+            {
+                await DocumentStore.Maintenance.SendAsync(new StartIndexOperation(indexName));
+            }
+        }
+    }
+}