Set the correct default theme when migrating settings

GH-102

Author: TolikPylypchuk

src/KeyboardSwitch.Core/Services/Settings/JsonSettingsService.cs

@@ -16,6 +16,8 @@ internal sealed class JsonSettingsService(
     ILogger<JsonSettingsService> logger)
     : IAppSettingsService
 {
+    private static readonly Version VersionWithAppThemes = new(4, 3, 0);
+
     private readonly IFileInfo file = fileSystem.FileInfo.New(
         Environment.ExpandEnvironmentVariables(globalSettings.Value.SettingsFilePath));
 
@@ -101,7 +103,11 @@ private async Task MigrateSettingsToLatestVersion(AppSettings settings)
             settings.AppVersion,
             newVersion);
 
-        await this.SaveAppSettings(settings with { AppVersion = newVersion });
+        var newSettings = settings.AppVersion < VersionWithAppThemes
+            ? settings with { AppTheme = this.GetDefaultTheme(), AppThemeVariant = AppThemeVariant.Auto }
+            : settings;
+
+        await this.SaveAppSettings(newSettings with { AppVersion = newVersion });
     }
 
     private AppSettings CreateDefaultAppSettings() =>
@@ -120,9 +126,7 @@ private AppSettings CreateDefaultAppSettings() =>
             ShowUninstalledLayoutsMessage = true,
             UseXsel = false,
             AppVersion = this.GetAppVersion(),
-            AppTheme = OperatingSystem.IsMacOS()
-                ? AppTheme.MacOS
-                : OperatingSystem.IsLinux() ? AppTheme.Simple : AppTheme.Fluent,
+            AppTheme = this.GetDefaultTheme(),
             AppThemeVariant = AppThemeVariant.Auto
         };
 
@@ -154,4 +158,9 @@ private IReadOnlyList<KeyboardLayout> GetKeyboardLayouts()
 
     private Version GetAppVersion() =>
         Assembly.GetExecutingAssembly()?.GetName().Version ?? new Version(0, 0);
+
+    private AppTheme GetDefaultTheme() =>
+        OperatingSystem.IsMacOS()
+            ? AppTheme.MacOS
+            : OperatingSystem.IsLinux() ? AppTheme.Simple : AppTheme.Fluent;
 }

src/KeyboardSwitch.Settings/KeyboardSwitch.Settings.csproj

@@ -20,7 +20,7 @@
     <PackageReference Include="Avalonia.Diagnostics" Version="11.3.1" />
     <PackageReference Include="Avalonia.ReactiveUI" Version="11.3.1" />
     <PackageReference Include="Avalonia.Themes.Simple" Version="11.3.1" />
-    <PackageReference Include="Devolutions.AvaloniaTheme.MacOS" Version="2025.6.12" />
+    <PackageReference Include="Devolutions.AvaloniaTheme.MacOS" Version="2025.6.19" />
     <PackageReference Include="DynamicData" Version="9.4.1" />
     <PackageReference Include="FluentAvaloniaUI" Version="2.3.0" />
     <PackageReference Include="Microsoft.Extensions.Configuration" Version="9.0.6" />

test/KeyboardSwitch.Tests/Services/JsonSettingsServiceTests.cs

@@ -182,11 +182,7 @@ public async Task GetAppSettingsDefault()
         Assert.True(settings.ShowUninstalledLayoutsMessage);
         Assert.Equal(Version, settings.AppVersion);
 
-        var expectedTheme = OperatingSystem.IsMacOS()
-            ? AppTheme.MacOS
-            : OperatingSystem.IsLinux() ? AppTheme.Simple : AppTheme.Fluent;
-
-        Assert.Equal(expectedTheme, settings.AppTheme);
+        Assert.Equal(this.GetExpectedDefaultTheme(), settings.AppTheme);
         Assert.Equal(AppThemeVariant.Auto, settings.AppThemeVariant);
 
         layoutService.Received().GetKeyboardLayouts();
@@ -325,6 +321,10 @@ public async Task GetAppSettingsMigrateVersion()
         Assert.True(settings.InstantSwitching);
         Assert.True(settings.SwitchLayout);
         Assert.True(settings.ShowUninstalledLayoutsMessage);
+
+        Assert.Equal(this.GetExpectedDefaultTheme(), settings.AppTheme);
+        Assert.Equal(AppThemeVariant.Auto, settings.AppThemeVariant);
+
         Assert.Equal(Version, settings.AppVersion);
     }
 
@@ -551,4 +551,9 @@ public async Task SaveAppSettings()
         var actualJson = JsonNode.Parse(file.TextContents);
         Assert.True(JsonNode.DeepEquals(expectedJson, actualJson));
     }
+
+    private AppTheme GetExpectedDefaultTheme() =>
+        OperatingSystem.IsMacOS()
+            ? AppTheme.MacOS
+            : OperatingSystem.IsLinux() ? AppTheme.Simple : AppTheme.Fluent;
 }