From 468dc6e922e6602549c24c4b44a6872acb324f66 Mon Sep 17 00:00:00 2001
From: kgame <kgamecarter@gmail.com>
Date: Tue, 28 Jul 2026 13:27:57 +0800
Subject: [PATCH] Fix no-reflection Console.Title crash (#213)

---
 src/bflat.Tests/BflatCompilationResult.cs |  5 +++--
 src/bflat.Tests/UnitTest1.cs              | 24 ++++++++++++++++++++++-
 src/bflat/BuildCommand.cs                 |  2 +-
 src/bflat/SpanMetadataBlockingPolicy.cs   | 17 ++++++++++++++++
 4 files changed, 44 insertions(+), 4 deletions(-)
 create mode 100644 src/bflat/SpanMetadataBlockingPolicy.cs

diff --git a/src/bflat.Tests/BflatCompilationResult.cs b/src/bflat.Tests/BflatCompilationResult.cs
index 80c0663..359d2d7 100644
--- a/src/bflat.Tests/BflatCompilationResult.cs
+++ b/src/bflat.Tests/BflatCompilationResult.cs
@@ -22,13 +22,14 @@ public void Run(string expectedOutput = null)
             }
 
             string stdOut = p.StandardOutput.ReadToEnd();
+            string stdErr = p.StandardError.ReadToEnd();
             
+            Assert.True(p.ExitCode == 0, $"Non-zero exit code: {p.ExitCode}\nStdout:\n{stdOut}\nStderr:\n{stdErr}");
+
             if (expectedOutput != null)
             {
                 Assert.Equal(expectedOutput, stdOut);
             }
-
-            Assert.Equal(0, p.ExitCode);
         }
 
     }
diff --git a/src/bflat.Tests/UnitTest1.cs b/src/bflat.Tests/UnitTest1.cs
index 0abbe27..1c87d58 100644
--- a/src/bflat.Tests/UnitTest1.cs
+++ b/src/bflat.Tests/UnitTest1.cs
@@ -10,4 +10,26 @@ public void Test1()
     {
         new BflatCompilation().Build("System.Console.WriteLine(\"Hello\");").Run("Hello" + Environment.NewLine);
     }
-}
\ No newline at end of file
+
+    [Fact]
+    public void ConsoleTitleAndEnvironmentExitWorkWithReflectionDisabled()
+    {
+        new BflatCompilation().Build("""
+            using System;
+
+            public static class Program
+            {
+                public static void Main() => FailFast("Done", 0);
+
+                private static void FailFast(string msg, int code)
+                {
+                    Console.WriteLine(msg);
+                    _ = Console.Title;
+                    Environment.Exit(code);
+                }
+            }
+            """, "--no-reflection --no-stacktrace-data --no-globalization --no-exception-messages --optimize-space --no-debug-info")
+            .Run("Done" + Environment.NewLine);
+    }
+
+}
diff --git a/src/bflat/BuildCommand.cs b/src/bflat/BuildCommand.cs
index 0ff3ca9..e5ab20a 100644
--- a/src/bflat/BuildCommand.cs
+++ b/src/bflat/BuildCommand.cs
@@ -586,7 +586,7 @@ public override int Handle(ParseResult result)
         }
         else
         {
-            mdBlockingPolicy = new FullyBlockedMetadataBlockingPolicy();
+            mdBlockingPolicy = new SpanMetadataBlockingPolicy();
             resBlockingPolicy = new FullyBlockedManifestResourceBlockingPolicy();
         }
         DynamicInvokeThunkGenerationPolicy invokeThunkGenerationPolicy = new DefaultDynamicInvokeThunkGenerationPolicy();
diff --git a/src/bflat/SpanMetadataBlockingPolicy.cs b/src/bflat/SpanMetadataBlockingPolicy.cs
new file mode 100644
index 0000000..2c481d6
--- /dev/null
+++ b/src/bflat/SpanMetadataBlockingPolicy.cs
@@ -0,0 +1,17 @@
+using ILCompiler;
+using Internal.TypeSystem;
+
+// .NET 10 Console.Title formats its result through Span<char>.ToString().
+// Keep only the metadata needed for that virtual call when reflection is disabled.
+internal sealed class SpanMetadataBlockingPolicy : FullyBlockedMetadataBlockingPolicy
+{
+    public override bool IsBlocked(MetadataType type) => !IsSpanType(type) && base.IsBlocked(type);
+
+    public override bool IsBlocked(MethodDesc method) => !(IsSpanType(method.OwningType) && method.Name == "ToString") && base.IsBlocked(method);
+
+    public override bool IsBlocked(FieldDesc field) => base.IsBlocked(field);
+
+    private static bool IsSpanType(TypeDesc type) => type is MetadataType metadataType
+        && metadataType.Namespace == "System"
+        && metadataType.Name == "Span`1";
+}