Fix file encoding to UTF-8 for all scaffolded files

src/MSIdentityScaffolding/Microsoft.DotNet.MSIdentity/CodeReaderWriter/CodeWriter.cs

@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Text;
 using Microsoft.DotNet.MSIdentity.AuthenticationParameters;
 using Microsoft.DotNet.MSIdentity.Project;
 using Microsoft.DotNet.MSIdentity.Properties;
@@ -47,7 +48,7 @@ internal static void WriteConfiguration(Summary summary, IEnumerable<Replacement
                     {
                         File.Copy(filePath, filePath + "%");
                     }
-                    File.WriteAllText(filePath, fileContent);
+                    File.WriteAllText(filePath, fileContent, new UTF8Encoding(false));
                 }
             }
         }

src/MSIdentityScaffolding/Microsoft.DotNet.MSIdentity/CodeReaderWriter/ProjectModifier.cs

@@ -335,7 +335,7 @@ private void AddFile(CodeFile file)
             if (!string.IsNullOrEmpty(fileDir))
             {
                 Directory.CreateDirectory(fileDir);
-                File.WriteAllText(filePath, codeFileString);
+                File.WriteAllText(filePath, codeFileString, new UTF8Encoding(false));
             }
         }
 

src/MSIdentityScaffolding/Microsoft.DotNet.MSIdentity/MicrosoftIdentityPlatform/AppSettingsModifier.cs

@@ -4,6 +4,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Text;
 using Microsoft.DotNet.MSIdentity.AuthenticationParameters;
 using Microsoft.DotNet.MSIdentity.Tool;
 using Newtonsoft.Json.Linq;
@@ -70,7 +71,7 @@ public void ModifyAppSettings(ApplicationParameters applicationParameters, IEnum
             // TODO: save comments somehow, only write to appsettings.json if changes are made
             if (modifiedAppSettings != null)
             {
-                System.IO.File.WriteAllText(_provisioningToolOptions.AppSettingsFilePath, modifiedAppSettings.ToString());
+                System.IO.File.WriteAllText(_provisioningToolOptions.AppSettingsFilePath, modifiedAppSettings.ToString(), new UTF8Encoding(false));
             }
         }
 

src/MSIdentityScaffolding/Microsoft.DotNet.MSIdentity/Tool/AppProvisioningTool.cs

@@ -563,7 +563,7 @@ private ProjectAuthenticationSettings ConvertAadApplicationToB2CApplication(Proj
                             + updatedContent.Substring(indexCallbackPath);
                     }
                 }
-                System.IO.File.WriteAllText(filePath, updatedContent);
+                System.IO.File.WriteAllText(filePath, updatedContent, new UTF8Encoding(false));
             }
 
             if (projectSettings.ApplicationParameters.CallsMicrosoftGraph)

src/Scaffolding/VS.Web.CG.Mvc/Dependency/ReadMeGenerator.cs

@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
+using System.Text;
 using System.Threading.Tasks;
 using Microsoft.DotNet.Scaffolding.Shared.Project;
 using Microsoft.DotNet.Scaffolding.Shared.ProjectModel;
@@ -103,7 +104,7 @@ public void GenerateReadMeWithContent(string content)
                 Constants.ReadMeOutputFileName);
             try
             {
-                File.WriteAllText(outputPath, content);
+                File.WriteAllText(outputPath, content, new UTF8Encoding(false));
             }
             catch (Exception ex)
             {

src/Shared/Microsoft.DotNet.Scaffolding.Shared/CodeModifier/DocumentBuilder.cs

@@ -151,7 +151,7 @@ public async Task WriteToClassFileAsync(string filePath)
         {
             var changedDocument = GetDocument();
             var classFileTxt = await changedDocument.GetTextAsync();
-            File.WriteAllText(filePath, classFileTxt.ToString());
+            File.WriteAllText(filePath, classFileTxt.ToString(), new UTF8Encoding(false));
         }
 
         internal static BaseMethodDeclarationSyntax AddMethodParameters(BaseMethodDeclarationSyntax originalMethod, Method methodChanges, CodeChangeOptions options)

src/Shared/Microsoft.DotNet.Scaffolding.Shared/DefaultFileSystem.cs

@@ -4,6 +4,7 @@
 using System.Collections.Generic;
 using System.Diagnostics;
 using System.IO;
+using System.Text;
 using System.Threading.Tasks;
 
 namespace Microsoft.DotNet.Scaffolding.Shared
@@ -72,7 +73,7 @@ public void RemoveDirectory(string path, bool recursive)
 
         public void WriteAllText(string path, string contents)
         {
-            File.WriteAllText(path, contents);
+            File.WriteAllText(path, contents, new UTF8Encoding(false));
         }
     }
 }

src/Shared/Microsoft.DotNet.Scaffolding.Shared/DotNetDispatcher/DotnetToolDispatcher.cs

@@ -8,6 +8,7 @@
 using System.Linq;
 using System.Reflection;
 using System.Runtime.Versioning;
+using System.Text;
 
 namespace Microsoft.Extensions.Internal
 {
@@ -100,7 +101,7 @@ private static void EnsureBindingRedirects(string assemblyFullPath, string toolN
             {
                 var text = File.ReadAllText(bindingRedirectFile);
                 var toolBindingRedirectFile = Path.Combine(Path.GetDirectoryName(assemblyFullPath), $"{toolName}.config");
-                File.WriteAllText(toolBindingRedirectFile, text);
+                File.WriteAllText(toolBindingRedirectFile, text, new UTF8Encoding(false));
             }
         }
 

src/dotnet-scaffolding/Microsoft.DotNet.Scaffolding.CodeModification/Helpers/ProjectModifierHelper.cs

@@ -499,7 +499,7 @@ internal static void ApplyReplacementsOnFileOnDisk(string filePath, IEnumerable<
 
         if (sourceChanged)
         {
-            File.WriteAllText(filePath, sourceFileString);
+            File.WriteAllText(filePath, sourceFileString, new UTF8Encoding(false));
         }
     }
 

src/dotnet-scaffolding/Microsoft.DotNet.Scaffolding.Internal/Services/FileSystem.cs

@@ -2,6 +2,7 @@
 
 using System.Diagnostics;
 using System.Reflection;
+using System.Text;
 
 namespace Microsoft.DotNet.Scaffolding.Internal.Services;
 
@@ -41,7 +42,7 @@ public string ReadAllText(string filePath)
     /// <inheritdoc />
     public void WriteAllText(string filePath, string content)
     {
-        File.WriteAllText(filePath, content);
+        File.WriteAllText(filePath, content, new UTF8Encoding(false));
     }
 
     /// <inheritdoc />
@@ -53,7 +54,7 @@ public string[] ReadAllLines(string filePath)
     /// <inheritdoc />
     public void WriteAllLines(string filePath, string[] content)
     {
-        File.WriteAllLines(filePath, content);
+        File.WriteAllLines(filePath, content, new UTF8Encoding(false));
     }
 
     /// <inheritdoc />

src/dotnet-scaffolding/Microsoft.DotNet.Scaffolding.TextTemplating/TextTemplatingStep.cs

@@ -1,5 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
+using System.Text;
 using Microsoft.DotNet.Scaffolding.Core.Scaffolders;
 using Microsoft.DotNet.Scaffolding.Core.Steps;
 using Microsoft.Extensions.Logging;
@@ -92,7 +93,7 @@ public override Task<bool> ExecuteAsync(ScaffolderContext context, CancellationT
                     // If Overwrite is true, write file, or if it doesn't exist
                     if (Overwrite || !File.Exists(templatingProperty.OutputPath))
                     {
-                        File.WriteAllText(templatingProperty.OutputPath, templatedString);
+                        File.WriteAllText(templatingProperty.OutputPath, templatedString, new UTF8Encoding(false));
                     }
                 }
             }

test/Shared/Microsoft.DotNet.Scaffolding.Shared.Tests/DefaultFileSystemEncodingTests.cs

@@ -0,0 +1,128 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.IO;
+using System.Text;
+using Microsoft.DotNet.Scaffolding.Shared;
+using Xunit;
+
+namespace Microsoft.DotNet.Scaffolding.Shared.Tests
+{
+    public class DefaultFileSystemEncodingTests
+    {
+        [Fact]
+        public void WriteAllText_UsesUtf8EncodingWithoutBom()
+        {
+            // Arrange
+            var fileSystem = new DefaultFileSystem();
+            var tempFile = Path.Combine(Path.GetTempPath(), $"test_{Guid.NewGuid()}.txt");
+            var contentWithNonAscii = "Hello мир 世界 العالم"; // Russian, Chinese, Arabic
+
+            try
+            {
+                // Act
+                fileSystem.WriteAllText(tempFile, contentWithNonAscii);
+
+                // Assert
+                var bytes = File.ReadAllBytes(tempFile);
+
+                // Check that file does NOT start with UTF-8 BOM (EF BB BF)
+                Assert.False(bytes.Length >= 3 && bytes[0] == 0xEF && bytes[1] == 0xBB && bytes[2] == 0xBF,
+                    "File should not contain UTF-8 BOM");
+
+                // Check that content can be read correctly as UTF-8
+                var readContent = File.ReadAllText(tempFile, Encoding.UTF8);
+                Assert.Equal(contentWithNonAscii, readContent);
+
+                // Verify encoding by reading with UTF8 encoding explicitly
+                using (var reader = new StreamReader(tempFile, new UTF8Encoding(false)))
+                {
+                    var content = reader.ReadToEnd();
+                    Assert.Equal(contentWithNonAscii, content);
+                }
+            }
+            finally
+            {
+                // Cleanup
+                if (File.Exists(tempFile))
+                {
+                    File.Delete(tempFile);
+                }
+            }
+        }
+
+        [Fact]
+        public void WriteAllText_PreservesNonAsciiCharacters()
+        {
+            // Arrange
+            var fileSystem = new DefaultFileSystem();
+            var tempFile = Path.Combine(Path.GetTempPath(), $"test_{Guid.NewGuid()}.txt");
+            var testCases = new[]
+            {
+                "Русский текст", // Russian
+                "中文文本", // Chinese
+                "النص العربي", // Arabic
+                "Ελληνικό κείμενο", // Greek
+                "日本語のテキスト", // Japanese
+                "한국어 텍스트", // Korean
+                "Émojis: 😀🎉🌟" // Emojis
+            };
+
+            try
+            {
+                foreach (var testContent in testCases)
+                {
+                    // Act
+                    fileSystem.WriteAllText(tempFile, testContent);
+
+                    // Assert
+                    var readContent = File.ReadAllText(tempFile, Encoding.UTF8);
+                    Assert.Equal(testContent, readContent);
+                }
+            }
+            finally
+            {
+                // Cleanup
+                if (File.Exists(tempFile))
+                {
+                    File.Delete(tempFile);
+                }
+            }
+        }
+
+        [Fact]
+        public void WriteAllText_DoesNotUseSystemDefaultEncoding()
+        {
+            // Arrange
+            var fileSystem = new DefaultFileSystem();
+            var tempFile = Path.Combine(Path.GetTempPath(), $"test_{Guid.NewGuid()}.txt");
+            var russianText = "Привет мир";
+
+            try
+            {
+                // Act
+                fileSystem.WriteAllText(tempFile, russianText);
+
+                // Assert - Try reading with default encoding (which might be different on different systems)
+                // If the file was written with UTF-8, it should read correctly
+                var bytes = File.ReadAllBytes(tempFile);
+                var utf8Content = Encoding.UTF8.GetString(bytes);
+                Assert.Equal(russianText, utf8Content);
+
+                // Verify it's not using some other encoding like Windows-1251
+                // If it were Windows-1251, these bytes would be different
+                var utf8Bytes = new UTF8Encoding(false).GetBytes(russianText);
+                Assert.Equal(utf8Bytes, bytes);
+            }
+            finally
+            {
+                // Cleanup
+                if (File.Exists(tempFile))
+                {
+                    File.Delete(tempFile);
+                }
+            }
+        }
+    }
+}

test/Shared/Microsoft.DotNet.Scaffolding.Shared.Tests/DocumentBuilderTests.cs

@@ -350,5 +350,105 @@ public void AddLeadingTriviaSpacesTests()
             Assert.True(formattedCodeSnippets[3].LeadingTrivia.NumberOfSpaces == 4 + whitespaceBeingAdded);
         }
 
+        [Fact]
+        public async Task WriteToClassFileAsync_UsesUtf8EncodingWithoutBom()
+        {
+            // Arrange
+            var tempFile = System.IO.Path.Combine(System.IO.Path.GetTempPath(), $"test_{Guid.NewGuid()}.cs");
+            var documentWithRussianComments = @"using System;
+
+namespace TestNamespace
+{
+    // Класс для тестирования
+    public class TestClass
+    {
+        // Метод с русскими комментариями
+        public void TestMethod()
+        {
+            var message = ""Привет, мир!"";
+        }
+    }
+}";
+
+            try
+            {
+                DocumentEditor editor = await DocumentEditor.CreateAsync(CreateDocument(documentWithRussianComments));
+                CodeFile codeFile = new CodeFile();
+                DocumentBuilder docBuilder = new DocumentBuilder(editor, codeFile, new MSIdentity.Shared.ConsoleLogger());
+
+                // Act
+                await docBuilder.WriteToClassFileAsync(tempFile);
+
+                // Assert
+                var bytes = System.IO.File.ReadAllBytes(tempFile);
+
+                // Check that file does NOT start with UTF-8 BOM (EF BB BF)
+                Assert.False(bytes.Length >= 3 && bytes[0] == 0xEF && bytes[1] == 0xBB && bytes[2] == 0xBF,
+                    "File should not contain UTF-8 BOM");
+
+                // Check that content can be read correctly as UTF-8
+                var readContent = System.IO.File.ReadAllText(tempFile, System.Text.Encoding.UTF8);
+                Assert.Contains("Привет, мир!", readContent);
+                Assert.Contains("Класс для тестирования", readContent);
+            }
+            finally
+            {
+                // Cleanup
+                if (System.IO.File.Exists(tempFile))
+                {
+                    System.IO.File.Delete(tempFile);
+                }
+            }
+        }
+
+        [Fact]
+        public async Task WriteToClassFileAsync_PreservesNonAsciiCharacters()
+        {
+            // Arrange
+            var tempFile = System.IO.Path.Combine(System.IO.Path.GetTempPath(), $"test_{Guid.NewGuid()}.cs");
+            var documentWithMultilingualComments = @"using System;
+
+namespace TestNamespace
+{
+    // English, Русский, 中文, العربية
+    public class MultilingualClass
+    {
+        public void TestMethod()
+        {
+            var message = ""Hello мир 世界 🌍"";
+        }
+    }
+}";
+
+            try
+            {
+                DocumentEditor editor = await DocumentEditor.CreateAsync(CreateDocument(documentWithMultilingualComments));
+                CodeFile codeFile = new CodeFile();
+                DocumentBuilder docBuilder = new DocumentBuilder(editor, codeFile, new MSIdentity.Shared.ConsoleLogger());
+
+                // Act
+                await docBuilder.WriteToClassFileAsync(tempFile);
+
+                // Assert
+                var readContent = System.IO.File.ReadAllText(tempFile, System.Text.Encoding.UTF8);
+                Assert.Contains("Hello мир 世界 🌍", readContent);
+                Assert.Contains("English, Русский, 中文, العربية", readContent);
+
+                // Verify UTF-8 encoding
+                var bytes = System.IO.File.ReadAllBytes(tempFile);
+                var utf8Content = System.Text.Encoding.UTF8.GetString(bytes);
+                Assert.Contains("мир", utf8Content);
+                Assert.Contains("世界", utf8Content);
+            }
+            finally
+            {
+                // Cleanup
+                if (System.IO.File.Exists(tempFile))
+                {
+                    System.IO.File.Delete(tempFile);
+                }
+            }
+        }
+
     }
 }