From 3c9bfbd041bfde3b86dd33a299432e97d73416b8 Mon Sep 17 00:00:00 2001
From: "Jeremy D. Miller" <jeremydmiller@yahoo.com>
Date: Tue, 29 Oct 2024 09:49:28 -0500
Subject: [PATCH] Fix for quick append + mandatory stream type behavior. Closes
 GH-3518

---
 .../mandatory_stream_type_behavior.cs         | 33 +++++++++++++++++++
 .../QuickAppendEventsOperationBase.cs         | 18 ++++++++--
 2 files changed, 49 insertions(+), 2 deletions(-)

diff --git a/src/EventSourcingTests/mandatory_stream_type_behavior.cs b/src/EventSourcingTests/mandatory_stream_type_behavior.cs
index 9bf20f5038..9938941236 100644
--- a/src/EventSourcingTests/mandatory_stream_type_behavior.cs
+++ b/src/EventSourcingTests/mandatory_stream_type_behavior.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Threading.Tasks;
 using EventSourcingTests.Aggregation;
+using EventSourcingTests.FetchForWriting;
 using JasperFx.Core;
 using Marten;
 using Marten.Events;
@@ -88,6 +89,38 @@ await Should.ThrowAsync<NonExistentStreamException>(async () =>
         });
     }
 
+    [Theory]
+    [InlineData(EventAppendMode.Rich, StreamIdentity.AsGuid)]
+    [InlineData(EventAppendMode.Rich, StreamIdentity.AsString)]
+    [InlineData(EventAppendMode.Quick, StreamIdentity.AsGuid)]
+    [InlineData(EventAppendMode.Quick, StreamIdentity.AsString)]
+    public async Task happy_path_append_event_after_the_stream_exists(EventAppendMode mode, StreamIdentity identity)
+    {
+        StoreOptions(opts =>
+        {
+            opts.Events.AppendMode = mode;
+            opts.Events.StreamIdentity = identity;
+            opts.Events.UseMandatoryStreamTypeDeclaration = true;
+        });
+
+        if (identity == StreamIdentity.AsGuid)
+        {
+            var streamId = Guid.NewGuid();
+            theSession.Events.StartStream<SimpleAggregate>(streamId, new BEvent());
+            await theSession.SaveChangesAsync();
+            theSession.Events.Append(streamId, new AEvent());
+            await theSession.SaveChangesAsync();
+        }
+        else
+        {
+            var streamId = Guid.NewGuid().ToString();
+            theSession.Events.StartStream<SimpleAggregate>(streamId, new BEvent());
+            await theSession.SaveChangesAsync();
+            theSession.Events.Append(streamId, new AEvent());
+            await theSession.SaveChangesAsync();
+        }
+    }
+
     [Fact]
     public async Task happy_path_usage_with_guid()
     {
diff --git a/src/Marten/Events/Operations/QuickAppendEventsOperationBase.cs b/src/Marten/Events/Operations/QuickAppendEventsOperationBase.cs
index f5595d5d01..916822609e 100644
--- a/src/Marten/Events/Operations/QuickAppendEventsOperationBase.cs
+++ b/src/Marten/Events/Operations/QuickAppendEventsOperationBase.cs
@@ -46,6 +46,13 @@ public void Postprocess(DbDataReader reader, IList<Exception> exceptions)
         {
             var values = reader.GetFieldValue<long[]>(0);
 
+            var finalVersion = values[0];
+            foreach (var e in Stream.Events.Reverse())
+            {
+                e.Version = finalVersion;
+                finalVersion--;
+            }
+
             // Ignore the first value
             for (int i = 1; i < values.Length; i++)
             {
@@ -53,7 +60,7 @@ public void Postprocess(DbDataReader reader, IList<Exception> exceptions)
                 Stream.Events[i - 1].Sequence = values[i];
             }
 
-            if (Events is { UseMandatoryStreamTypeDeclaration: true } && Stream.Events[0].Version == 0)
+            if (Events is { UseMandatoryStreamTypeDeclaration: true } && Stream.Events[0].Version == 1)
             {
                 throw new NonExistentStreamException(Events.StreamIdentity == StreamIdentity.AsGuid
                     ? Stream.Id
@@ -119,6 +126,13 @@ public async Task PostprocessAsync(DbDataReader reader, IList<Exception> excepti
         {
             var values = await reader.GetFieldValueAsync<long[]>(0, token).ConfigureAwait(false);
 
+            var finalVersion = values[0];
+            foreach (var e in Stream.Events.Reverse())
+            {
+                e.Version = finalVersion;
+                finalVersion--;
+            }
+
             // Ignore the first value
             for (int i = 1; i < values.Length; i++)
             {
@@ -126,7 +140,7 @@ public async Task PostprocessAsync(DbDataReader reader, IList<Exception> excepti
                 Stream.Events[i - 1].Sequence = values[i];
             }
 
-            if (Events is { UseMandatoryStreamTypeDeclaration: true } && Stream.Events[0].Version == 0)
+            if (Events is { UseMandatoryStreamTypeDeclaration: true } && Stream.Events[0].Version == 1)
             {
                 throw new NonExistentStreamException(Events.StreamIdentity == StreamIdentity.AsGuid
                     ? Stream.Id