Add config file support and move previews setting from manifest

src/dnvm/CommandLineArguments.cs

@@ -14,9 +14,6 @@ namespace Dnvm;
 [Command("dnvm", Summary = "Install and manage .NET SDKs.")]
 public partial record DnvmArgs
 {
-    [CommandOption("--enable-dnvm-previews", Description = "Enable dnvm previews.")]
-    public bool? EnableDnvmPreviews { get; init; }
-
     [CommandGroup("command")]
     public DnvmSubCommand? SubCommand { get; init; }
 }
@@ -246,7 +243,7 @@ public static class CommandLineArguments
         {
             case CmdLine.ParsedArgsOrHelpInfos<DnvmArgs>.Parsed(var value):
                 dnvmCmd = value;
-                if (dnvmCmd.EnableDnvmPreviews is null && dnvmCmd.SubCommand is null)
+                if (dnvmCmd.SubCommand is null)
                 {
                     // Empty command is a help request.
                     console.WriteLine(CmdLine.GetHelpText<DnvmArgs>(includeHelp: true));

src/dnvm/DnvmConfig.cs

@@ -0,0 +1,154 @@
+using System;
+using System.IO;
+using System.Runtime.InteropServices;
+using System.Text;
+using System.Threading.Tasks;
+using Serde;
+using Serde.Json;
+using Zio;
+using Zio.FileSystems;
+
+namespace Dnvm;
+
+/// <summary>
+/// Represents the dnvm configuration file.
+/// </summary>
+[GenerateSerde]
+public sealed partial record DnvmConfig
+{
+    public static readonly DnvmConfig Default = new();
+
+    /// <summary>
+    /// Whether to enable dnvm preview releases in the update command.
+    /// </summary>
+    public bool PreviewsEnabled { get; init; } = false;
+}
+
+/// <summary>
+/// Static methods for config file operations.
+/// </summary>
+public static class DnvmConfigFile
+{
+    private const string ConfigFileName = "dnvmConfig.json";
+
+    // Allow tests to override the config directory
+    public static string? TestConfigDirectory { get; set; }
+
+    /// <summary>
+    /// Get the platform-specific config directory path.
+    /// - Linux: ~/.config/dnvm/ (XDG_CONFIG_HOME/dnvm)
+    /// - macOS: ~/Library/Application Support/dnvm/
+    /// - Windows: %LOCALAPPDATA%/dnvm/
+    /// </summary>
+    private static string GetConfigDirectory()
+    {
+        if (TestConfigDirectory is not null)
+        {
+            return TestConfigDirectory;
+        }
+
+        // Allow tests to override config directory via environment variable
+        var testOverride = Environment.GetEnvironmentVariable("DNVM_TEST_CONFIG_DIR");
+        if (!string.IsNullOrWhiteSpace(testOverride))
+        {
+            return testOverride;
+        }
+
+        if (RuntimeInformation.IsOSPlatform(OSPlatform.Linux))
+        {
+            // Use XDG_CONFIG_HOME on Linux, defaulting to ~/.config
+            var xdgConfigHome = Environment.GetEnvironmentVariable("XDG_CONFIG_HOME");
+            var configBase = string.IsNullOrWhiteSpace(xdgConfigHome)
+                ? Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile), ".config")
+                : xdgConfigHome;
+            return Path.Combine(configBase, "dnvm");
+        }
+        else
+        {
+            // On macOS and Windows, use LocalApplicationData
+            // This is ~/Library/Application Support on macOS and %LOCALAPPDATA% on Windows
+            return Path.Combine(
+                Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData),
+                "dnvm");
+        }
+    }
+
+    private static IFileSystem GetConfigFileSystem()
+    {
+        var configDir = GetConfigDirectory();
+        Directory.CreateDirectory(configDir);
+        return new SubFileSystem(
+            DnvmEnv.PhysicalFs,
+            DnvmEnv.PhysicalFs.ConvertPathFromInternal(configDir));
+    }
+
+    private static UPath ConfigPath => UPath.Root / ConfigFileName;
+
+    /// <summary>
+    /// Reads the config file from the platform-specific config directory.
+    /// Returns the default config if the file does not exist.
+    /// </summary>
+    public static DnvmConfig Read()
+    {
+        try
+        {
+            var fs = GetConfigFileSystem();
+            if (!fs.FileExists(ConfigPath))
+            {
+                return DnvmConfig.Default;
+            }
+
+            var text = fs.ReadAllText(ConfigPath);
+            return JsonSerializer.Deserialize<DnvmConfig>(text);
+        }
+        catch (Exception)
+        {
+            // If there's any error reading or parsing the config, return default
+            return DnvmConfig.Default;
+        }
+    }
+
+    /// <summary>
+    /// Writes the config file to the platform-specific config directory.
+    /// </summary>
+    public static void Write(DnvmConfig config)
+    {
+        var fs = GetConfigFileSystem();
+        var tempFileName = $"{ConfigFileName}.{Path.GetRandomFileName()}.tmp";
+        var tempPath = UPath.Root / tempFileName;
+
+        var text = JsonSerializer.Serialize(config);
+
+        // Write to temporary file first
+        fs.WriteAllText(tempPath, text, Encoding.UTF8);
+
+        // Create backup of existing config if it exists
+        if (fs.FileExists(ConfigPath))
+        {
+            var backupPath = UPath.Root / $"{ConfigFileName}.backup";
+            try
+            {
+                // Should not throw if the file doesn't exist
+                fs.DeleteFile(backupPath);
+                fs.MoveFile(ConfigPath, backupPath);
+            }
+            catch (IOException)
+            {
+                // Best effort cleanup - ignore if we can't delete the backup file
+            }
+        }
+
+        // Atomic rename operation
+        fs.MoveFile(tempPath, ConfigPath);
+
+        // Clean up temporary file
+        try
+        {
+            fs.DeleteFile(tempPath);
+        }
+        catch (IOException)
+        {
+            // Best effort cleanup - ignore if we can't delete the temp file
+        }
+    }
+}

src/dnvm/Manifest.cs

@@ -41,7 +41,6 @@ public sealed partial record Manifest
 {
     public static readonly Manifest Empty = new();
 
-    public bool PreviewsEnabled { get; init; } = false;
     public SdkDirName CurrentSdkDir { get; init; } = DnvmEnv.DefaultSdkDirName;
     public EqArray<InstalledSdk> InstalledSdks { get; init; } = [];
     public EqArray<RegisteredChannel> RegisteredChannels { get; init; } = [];

src/dnvm/ManifestSchema/ManifestSerialize.cs

@@ -70,7 +70,6 @@ public static Manifest Convert(this ManifestV9 manifestV9)
     {
         return new Manifest
         {
-            PreviewsEnabled = manifestV9.PreviewsEnabled,
             CurrentSdkDir = manifestV9.CurrentSdkDir.Convert(),
             InstalledSdks = manifestV9.InstalledSdks.SelectAsArray(sdk => new InstalledSdk
             {
@@ -94,7 +93,7 @@ internal static ManifestV9 ConvertToLatest(this Manifest @this)
     {
         return new ManifestV9
         {
-            PreviewsEnabled = @this.PreviewsEnabled,
+            PreviewsEnabled = false, // Always write false since this is now in config file
             CurrentSdkDir = @this.CurrentSdkDir.ConvertToLatest(),
             InstalledSdks = @this.InstalledSdks.SelectAsArray(sdk => new InstalledSdkV9
             {

src/dnvm/Program.cs

@@ -32,29 +32,13 @@ public static async Task<int> Main(string[] args)
         using var env = DnvmEnv.CreateDefault();
         if (parsedArgs.SubCommand is null)
         {
-            if (parsedArgs.EnableDnvmPreviews == true)
-            {
-                return await EnableDnvmPreviews(env);
-            }
-            else
-            {
-                // Help was requested, exit with success.
-                return 0;
-            }
+            // Help was requested, exit with success.
+            return 0;
         }
 
         return await Dnvm(env, logger, parsedArgs);
     }
 
-    public static async Task<int> EnableDnvmPreviews(DnvmEnv env)
-    {
-        using var @lock = await ManifestLock.Acquire(env);
-        var manifest = await @lock.ReadOrCreateManifest(env);
-        manifest = manifest with { PreviewsEnabled = true };
-        await @lock.WriteManifest(env, manifest);
-        return 0;
-    }
-
     internal static async Task<int> Dnvm(DnvmEnv env, Logger logger, DnvmArgs args)
     {
         return args.SubCommand switch

src/dnvm/UpdateCommand.cs

@@ -126,7 +126,8 @@ public static async Task<Result> UpdateSdks(
     {
         env.Console.WriteLine("Looking for available updates");
         // Check for dnvm updates
-        if (await CheckForSelfUpdates(env.HttpClient, env.Console, logger, releasesUrl, manifest.PreviewsEnabled) is (true, _))
+        var config = DnvmConfigFile.Read();
+        if (await CheckForSelfUpdates(env.HttpClient, env.Console, logger, releasesUrl, config.PreviewsEnabled) is (true, _))
         {
             env.Console.WriteLine("dnvm is out of date. Run 'dnvm update --self' to update dnvm.");
         }
@@ -243,8 +244,9 @@ public async Task<Result> UpdateSelf(Manifest manifest)
             return Result.NotASingleFile;
         }
 
+        var config = DnvmConfigFile.Read();
         DnvmReleases.Release release;
-        switch (await CheckForSelfUpdates(_env.HttpClient, _env.Console, _logger, _releasesUrl, manifest.PreviewsEnabled))
+        switch (await CheckForSelfUpdates(_env.HttpClient, _env.Console, _logger, _releasesUrl, config.PreviewsEnabled))
         {
             case (false, null):
                 return Result.SelfUpdateFailed;

test/IntegrationTests/Runner.cs

@@ -21,14 +21,20 @@ internal static class DnvmRunner
         }
         try
         {
+            var envVars = new Dictionary<string, string>
+            {
+                ["HOME"] = env.UserHome,
+                ["DNVM_HOME"] = env.RealPath(UPath.Root)
+            };
+            // Use the test config directory if it's set
+            if (DnvmConfigFile.TestConfigDirectory is not null)
+            {
+                envVars["DNVM_TEST_CONFIG_DIR"] = DnvmConfigFile.TestConfigDirectory;
+            }
             var procResult = await ProcUtil.RunWithOutput(
                 dnvmPath,
                 dnvmArgs,
-                new()
-                {
-                    ["HOME"] = env.UserHome,
-                    ["DNVM_HOME"] = env.RealPath(UPath.Root)
-                }
+                envVars
             );
             // Allow the test to check the environment variables before they are restored
             envChecker?.Invoke();

test/IntegrationTests/SelfInstallTests.cs

@@ -305,23 +305,17 @@ public Task UpdateSelfPreview() => RunWithServer(async (mockServer, env) =>
         Assert.True(timeAfterUpdate == timeBeforeUpdate);
         Assert.Contains("Dnvm is up-to-date", result.Out);
 
-        result = await ProcUtil.RunWithOutput(
-            copiedExe,
-            $"--enable-dnvm-previews",
-            new() {
-                ["HOME"] = env.UserHome,
-                ["DNVM_HOME"] = env.RealPath(UPath.Root)
-            }
-        );
-        Assert.Equal(0, result.ExitCode);
+        // Manually create config file with previews enabled
+        var config = new DnvmConfig { PreviewsEnabled = true };
+        DnvmConfigFile.Write(config);
 
         result = await DnvmRunner.RunAndRestoreEnv(
             env,
             copiedExe,
             $"update --self --dnvm-url {mockServer.DnvmReleasesUrl} -v"
         );
-        timeAfterUpdate = File.GetLastWriteTimeUtc(copiedExe);
-        Assert.True(timeAfterUpdate > timeBeforeUpdate);
+        var timeAfterPreviewUpdate = File.GetLastWriteTimeUtc(copiedExe);
+        Assert.True(timeAfterPreviewUpdate > timeBeforeUpdate);
         Assert.Contains("Process successfully upgraded", result.Out);
     });
 

test/IntegrationTests/UpdateTests.cs

@@ -51,8 +51,9 @@ public async Task EnablePreviewsAndDownload() => await TestWithServer(async (moc
         Assert.Contains("dnvm is up-to-date", output, StringComparison.OrdinalIgnoreCase);
         Assert.Equal(0, proc.ExitCode);
 
-        proc = await DnvmRunner.RunAndRestoreEnv(env, SelfInstallTests.DnvmExe, "--enable-dnvm-previews");
-        Assert.Equal(0, proc.ExitCode);
+        // Manually create config file with previews enabled
+        var config = new DnvmConfig { PreviewsEnabled = true };
+        DnvmConfigFile.Write(config);
 
         proc = await DnvmRunner.RunAndRestoreEnv(env, SelfInstallTests.DnvmExe,
             $"update --self -v --dnvm-url {mockServer.DnvmReleasesUrl}");

test/Shared/TestOptions.cs

@@ -1,4 +1,5 @@
 
+using System.IO;
 using Spectre.Console.Testing;
 using Zio;
 using Zio.FileSystems;
@@ -10,9 +11,11 @@ public sealed class TestEnv : IDisposable
     private readonly TempDirectory _userHome = TestUtils.CreateTempDirectory();
     private readonly TempDirectory _dnvmHome = TestUtils.CreateTempDirectory();
     private readonly TempDirectory _workingDir = TestUtils.CreateTempDirectory();
+    private readonly TempDirectory _configDir = TestUtils.CreateTempDirectory();
     private readonly Dictionary<string, string> _envVars = new();
 
     public DnvmEnv DnvmEnv { get; init; }
+    public string ConfigDirPath => _configDir.Path;
 
     public TestEnv(
         string dotnetFeedUrl,
@@ -26,6 +29,9 @@ public TestEnv(
         var cwdFs = new SubFileSystem(physicalFs, physicalFs.ConvertPathFromInternal(_workingDir.Path));
         cwdFs.CreateDirectory(cwd);
 
+        // Set the test config directory
+        DnvmConfigFile.TestConfigDirectory = _configDir.Path;
+
         DnvmEnv = new DnvmEnv(
                 userHome: _userHome.Path,
                 dnvmFs,
@@ -43,6 +49,9 @@ public void Dispose()
     {
         _userHome.Dispose();
         _dnvmHome.Dispose();
+        _workingDir.Dispose();
+        _configDir.Dispose();
+        DnvmConfigFile.TestConfigDirectory = null;
         DnvmEnv.Dispose();
     }
 }

test/UnitTests/CommandLineTests.cs

@@ -9,12 +9,11 @@ namespace Dnvm.Test;
 public sealed class CommandLineTests
 {
     private static readonly string ExpectedHelpText = """
-        usage: dnvm [--enable-dnvm-previews] [-h | --help] <command>
+        usage: dnvm [-h | --help] <command>
 
         Install and manage .NET SDKs.
 
         Options:
-            --enable-dnvm-previews  Enable dnvm previews.
             -h, --help  Show help information.
 
         Commands:
@@ -177,15 +176,6 @@ public void TrackMixedCase()
         });
     }
 
-    [Fact]
-    public void EnableDnvmPreviews()
-    {
-        var options = CommandLineArguments.ParseRaw(new TestConsole(), [
-            "--enable-dnvm-previews",
-        ]);
-        Assert.True(options!.EnableDnvmPreviews);
-    }
-
     [Theory]
     [InlineData("-h")]
     [InlineData("--help")]

test/UnitTests/ManifestTests.cs

@@ -136,8 +136,7 @@ public void WriteManifestV9()
                     InstalledSdkVersions = [ SemVersion.Parse("8.0.100-preview.3.23178.7", SemVersionStyles.Strict) ]
                 }
             ],
-            CurrentSdkDir = new SdkDirName("dn"),
-            PreviewsEnabled = false
+            CurrentSdkDir = new SdkDirName("dn")
         };
         var expected = """
 {