From 2036f17d8935e1af7efaf3353c67b89cfa57ed20 Mon Sep 17 00:00:00 2001
From: Tanner Gooding <tagoo@outlook.com>
Date: Sun, 12 Jul 2026 22:17:28 -0700
Subject: [PATCH] Don't emit a namespace closing brace for file-scoped
 namespaces in single-file output

When generating a single output file, the namespace closing brace was written
unconditionally after all output builders. File-scoped namespaces emit no opening
brace, so this produced a stray trailing brace and invalid C#. Skip the closing
brace (for both the primary and test streams) when file-scoped namespaces are used.

Fixes #555

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
---
 .../PInvokeGenerator.Close.cs                 |  7 ++-
 .../FileScopedNamespaceTest.cs                | 58 +++++++++++++++++++
 2 files changed, 63 insertions(+), 2 deletions(-)
 create mode 100644 tests/ClangSharp.PInvokeGenerator.UnitTests/FileScopedNamespaceTest.cs

diff --git a/sources/ClangSharp.PInvokeGenerator/PInvokeGenerator.Close.cs b/sources/ClangSharp.PInvokeGenerator/PInvokeGenerator.Close.cs
index e63c552ec..c26564af3 100644
--- a/sources/ClangSharp.PInvokeGenerator/PInvokeGenerator.Close.cs
+++ b/sources/ClangSharp.PInvokeGenerator/PInvokeGenerator.Close.cs
@@ -286,7 +286,10 @@ public void Close()
 
             if (_config.OutputMode == PInvokeGeneratorOutputMode.CSharp)
             {
-                sw.WriteLine('}');
+                if (!_config.GenerateFileScopedNamespaces)
+                {
+                    sw.WriteLine('}');
+                }
             }
             else if (_config.OutputMode == PInvokeGeneratorOutputMode.Xml)
             {
@@ -299,7 +302,7 @@ public void Close()
                 using var tsw = new StreamWriter(testStream, s_defaultStreamWriterEncoding, DefaultStreamWriterBufferSize, leaveStreamOpen);
                 tsw.NewLine = "\n";
 
-                if (_config.OutputMode == PInvokeGeneratorOutputMode.CSharp)
+                if ((_config.OutputMode == PInvokeGeneratorOutputMode.CSharp) && !_config.GenerateFileScopedNamespaces)
                 {
                     tsw.WriteLine('}');
                 }
diff --git a/tests/ClangSharp.PInvokeGenerator.UnitTests/FileScopedNamespaceTest.cs b/tests/ClangSharp.PInvokeGenerator.UnitTests/FileScopedNamespaceTest.cs
new file mode 100644
index 000000000..9afe9e635
--- /dev/null
+++ b/tests/ClangSharp.PInvokeGenerator.UnitTests/FileScopedNamespaceTest.cs
@@ -0,0 +1,58 @@
+// Copyright (c) .NET Foundation and Contributors. All Rights Reserved. Licensed under the MIT License (MIT). See License.md in the repository root for more information.
+
+using System.Threading.Tasks;
+using NUnit.Framework;
+
+namespace ClangSharp.UnitTests;
+
+/// <summary>
+/// Regression test for https://github.com/dotnet/ClangSharp/issues/555.
+/// When <c>generate-file-scoped-namespaces</c> is used with a single output file, no namespace
+/// opening brace is emitted, so no closing brace must be emitted either.
+/// </summary>
+[Platform("win")]
+public sealed class FileScopedNamespaceTest : PInvokeGeneratorTest
+{
+    [Test]
+    public Task MethodClassHasNoTrailingBrace()
+    {
+        var inputContents = @"extern ""C"" void MyFunction();
+";
+
+        var expectedOutputContents = @"using System.Runtime.InteropServices;
+
+namespace ClangSharp.Test;
+
+public static partial class Methods
+{
+    [DllImport(""ClangSharpPInvokeGenerator"", CallingConvention = CallingConvention.Cdecl, ExactSpelling = true)]
+    public static extern void MyFunction();
+}
+";
+
+        return ValidateGeneratedCSharpLatestWindowsBindingsAsync(inputContents, expectedOutputContents, PInvokeGeneratorConfigurationOptions.GenerateFileScopedNamespaces);
+    }
+
+    [Test]
+    public Task StructHasNoTrailingBrace()
+    {
+        var inputContents = @"struct Point
+{
+    int x;
+    int y;
+};
+";
+
+        var expectedOutputContents = @"namespace ClangSharp.Test;
+
+public partial struct Point
+{
+    public int x;
+
+    public int y;
+}
+";
+
+        return ValidateGeneratedCSharpLatestWindowsBindingsAsync(inputContents, expectedOutputContents, PInvokeGeneratorConfigurationOptions.GenerateFileScopedNamespaces);
+    }
+}