From b644c4b83160ca1f446f8f5d2cdf2c3765894e08 Mon Sep 17 00:00:00 2001
From: JusterZhu <zhuzhen723723@outlook.com>
Date: Tue, 26 May 2026 14:12:22 +0800
Subject: [PATCH] refactor: change PipelineBuilder from LIFO (ImmutableStack)
 to FIFO (ImmutableQueue)
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The LIFO stack caused middleware execution order to be the reverse of
registration order, which was the root cause of the MacStrategy pipeline
bug fixed in #436. With FIFO (ImmutableQueue), registration order now
equals execution order for intuitive API semantics.

- PipelineBuilder: ImmutableStack → ImmutableQueue, Push → Enqueue
- All OS strategies: register Hash → Compress → Patch (executes in same order)
- MacStrategy: also changed to UseMiddlewareIf<PatchMiddleware> for consistency

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
---
 .../GeneralUpdate.Core/Pipeline/PipelineBuilder.cs   | 12 ++++++------
 src/c#/GeneralUpdate.Core/Strategy/LinuxStrategy.cs  |  4 ++--
 src/c#/GeneralUpdate.Core/Strategy/MacStrategy.cs    |  2 +-
 .../GeneralUpdate.Core/Strategy/WindowsStrategy.cs   |  4 ++--
 4 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/c#/GeneralUpdate.Core/Pipeline/PipelineBuilder.cs b/src/c#/GeneralUpdate.Core/Pipeline/PipelineBuilder.cs
index d75ef004..0dce594f 100644
--- a/src/c#/GeneralUpdate.Core/Pipeline/PipelineBuilder.cs
+++ b/src/c#/GeneralUpdate.Core/Pipeline/PipelineBuilder.cs
@@ -5,19 +5,19 @@
 namespace GeneralUpdate.Core.Pipeline
 {
     /// <summary>
-    /// Pipeline builder.
+    /// Pipeline builder — middleware execute in FIFO (registration) order.
     /// </summary>
     public sealed class PipelineBuilder(PipelineContext context)
     {
         /// <summary>
-        /// LIFO£¬Last In First Out.
+        /// LIFO£¬Last In First Out.
         /// </summary>
-        private ImmutableStack<IMiddleware> _middlewareStack = ImmutableStack<IMiddleware>.Empty;
+        private ImmutableQueue<IMiddleware> _middlewareQueue = ImmutableQueue<IMiddleware>.Empty;
 
         public PipelineBuilder UseMiddleware<TMiddleware>() where TMiddleware : IMiddleware, new()
         {
             var middleware = new TMiddleware();
-            _middlewareStack = _middlewareStack.Push(middleware);
+            _middlewareQueue = _middlewareQueue.Enqueue(middleware);
             return this;
         }
 
@@ -28,13 +28,13 @@ public PipelineBuilder UseMiddlewareIf<TMiddleware>(bool? condition)
                 return this;
             
             var middleware = new TMiddleware();
-            _middlewareStack = _middlewareStack.Push(middleware);
+            _middlewareQueue = _middlewareQueue.Enqueue(middleware);
             return this;
         }
 
         public async Task Build()
         {
-            foreach (var middleware in _middlewareStack)
+            foreach (var middleware in _middlewareQueue)
             {
                 await middleware.InvokeAsync(context);
             }
diff --git a/src/c#/GeneralUpdate.Core/Strategy/LinuxStrategy.cs b/src/c#/GeneralUpdate.Core/Strategy/LinuxStrategy.cs
index d1e2eab9..0fd5a75c 100644
--- a/src/c#/GeneralUpdate.Core/Strategy/LinuxStrategy.cs
+++ b/src/c#/GeneralUpdate.Core/Strategy/LinuxStrategy.cs
@@ -20,9 +20,9 @@ protected override PipelineBuilder BuildPipeline(PipelineContext context)
     {
         GeneralTracer.Info($"GeneralUpdate.Core.LinuxStrategy.BuildPipeline: assembling middleware pipeline. PatchEnabled={_configinfo.PatchEnabled}");
         var builder = new PipelineBuilder(context)
-            .UseMiddlewareIf<PatchMiddleware>(_configinfo.PatchEnabled)
+            .UseMiddleware<HashMiddleware>()
             .UseMiddleware<CompressMiddleware>()
-            .UseMiddleware<HashMiddleware>();
+            .UseMiddlewareIf<PatchMiddleware>(_configinfo.PatchEnabled);
         return builder;
     }
 
diff --git a/src/c#/GeneralUpdate.Core/Strategy/MacStrategy.cs b/src/c#/GeneralUpdate.Core/Strategy/MacStrategy.cs
index 11b998bc..7625f8b8 100644
--- a/src/c#/GeneralUpdate.Core/Strategy/MacStrategy.cs
+++ b/src/c#/GeneralUpdate.Core/Strategy/MacStrategy.cs
@@ -39,7 +39,7 @@ protected override PipelineBuilder BuildPipeline(PipelineContext context)
         var builder = new PipelineBuilder(context)
             .UseMiddleware<HashMiddleware>()
             .UseMiddleware<CompressMiddleware>()
-            .UseMiddleware<PatchMiddleware>();
+            .UseMiddlewareIf<PatchMiddleware>(_configinfo.PatchEnabled);
         return builder;
     }
 }
diff --git a/src/c#/GeneralUpdate.Core/Strategy/WindowsStrategy.cs b/src/c#/GeneralUpdate.Core/Strategy/WindowsStrategy.cs
index 8612ed3a..bf7e7811 100644
--- a/src/c#/GeneralUpdate.Core/Strategy/WindowsStrategy.cs
+++ b/src/c#/GeneralUpdate.Core/Strategy/WindowsStrategy.cs
@@ -27,9 +27,9 @@ protected override PipelineBuilder BuildPipeline(PipelineContext context)
         {
             GeneralTracer.Info($"GeneralUpdate.Core.WindowsStrategy.BuildPipeline: assembling middleware pipeline. PatchEnabled={_configinfo.PatchEnabled}");
             var builder = new PipelineBuilder(context)
-                .UseMiddlewareIf<PatchMiddleware>(_configinfo.PatchEnabled)
+                .UseMiddleware<HashMiddleware>()
                 .UseMiddleware<CompressMiddleware>()
-                .UseMiddleware<HashMiddleware>();
+                .UseMiddlewareIf<PatchMiddleware>(_configinfo.PatchEnabled);
             return builder;
         }