Give OmniSharp the ability to configure fallback analyzerconfigoptions

Author: JoeRobich

src/Features/ExternalAccess/OmniSharp/Microsoft.CodeAnalysis.ExternalAccess.OmniSharp.csproj

@@ -10,13 +10,14 @@
       https://github.com/OmniSharp/omnisharp-roslyn
     </PackageDescription>
   </PropertyGroup>
-  
+
   <ItemGroup>
     <InternalsVisibleTo Include="Microsoft.CodeAnalysis.ExternalAccess.OmniSharp.CSharp" />
     <InternalsVisibleTo Include="Microsoft.CodeAnalysis.ExternalAccess.OmniSharp.UnitTests" />
     <!--
       ⚠ ONLY OMNISHARP ASSEMBLIES MAY BE ADDED HERE ⚠
     -->
+    <InternalsVisibleTo Include="OmniSharp.Host" Key="$(OmniSharpKey)" />
     <InternalsVisibleTo Include="OmniSharp.Roslyn" Key="$(OmniSharpKey)" />
     <InternalsVisibleTo Include="OmniSharp.Roslyn.CSharp" Key="$(OmniSharpKey)" />
     <InternalsVisibleTo Include="OmniSharp.Roslyn.CSharp.Tests" Key="$(OmniSharpKey)" />

src/Features/ExternalAccess/OmniSharp/Options/OmniSharpEditorConfigOptions.cs

@@ -0,0 +1,13 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.CodeAnalysis.ExternalAccess.OmniSharp.ImplementType;
+
+namespace Microsoft.CodeAnalysis.ExternalAccess.OmniSharp.Options;
+
+internal sealed record class OmniSharpEditorConfigOptions
+{
+    public OmniSharpLineFormattingOptions LineFormattingOptions { get; init; } = new();
+    public OmniSharpImplementTypeOptions ImplementTypeOptions { get; init; } = new();
+}

src/Features/ExternalAccess/OmniSharp/Options/OmniSharpSolutionAnalyzerConfigOptionsUpdater.cs

@@ -0,0 +1,104 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System;
+using System.Collections.Immutable;
+using Microsoft.CodeAnalysis.Diagnostics;
+using Microsoft.CodeAnalysis.Formatting;
+using Microsoft.CodeAnalysis.ErrorReporting;
+using Microsoft.CodeAnalysis.Options;
+using Roslyn.Utilities;
+using Microsoft.CodeAnalysis.ImplementType;
+
+namespace Microsoft.CodeAnalysis.ExternalAccess.OmniSharp.Options;
+
+using Workspace = CodeAnalysis.Workspace;
+
+internal static class OmniSharpSolutionAnalyzerConfigOptionsUpdater
+{
+    internal static void UpdateOptions(Workspace workspace, OmniSharpEditorConfigOptions editorConfigOptions)
+    {
+        try
+        {
+            workspace.SetCurrentSolution(UpdateOptions, changeKind: WorkspaceChangeKind.SolutionChanged);
+
+            Solution UpdateOptions(Solution oldSolution)
+            {
+                var oldFallbackOptions = oldSolution.FallbackAnalyzerOptions;
+                oldFallbackOptions.TryGetValue(LanguageNames.CSharp, out var csharpFallbackOptions);
+
+                var changedOptions = DetermineChangedOptions(csharpFallbackOptions, editorConfigOptions);
+                if (changedOptions.IsEmpty)
+                {
+                    return oldSolution;
+                }
+
+                var builder = ImmutableDictionary.CreateBuilder<string, string>(AnalyzerConfigOptions.KeyComparer);
+                if (csharpFallbackOptions is not null)
+                {
+                    // copy existing option values:
+                    foreach (var oldKey in csharpFallbackOptions.Keys)
+                    {
+                        if (csharpFallbackOptions.TryGetValue(oldKey, out var oldValue))
+                        {
+                            builder.Add(oldKey, oldValue);
+                        }
+                    }
+                }
+
+                // update changed values:
+                foreach (var (key, value) in changedOptions)
+                {
+                    builder[key] = value;
+                }
+
+                var newFallbackOptions = oldFallbackOptions.SetItem(
+                    LanguageNames.CSharp,
+                    StructuredAnalyzerConfigOptions.Create(new DictionaryAnalyzerConfigOptions(builder.ToImmutable())));
+
+                return oldSolution.WithFallbackAnalyzerOptions(newFallbackOptions);
+            }
+        }
+        catch (Exception e) when (FatalError.ReportAndPropagate(e, ErrorSeverity.Diagnostic))
+        {
+            throw ExceptionUtilities.Unreachable();
+        }
+    }
+
+    private static ImmutableDictionary<string, string> DetermineChangedOptions(
+        StructuredAnalyzerConfigOptions? csharpFallbackOptions,
+        OmniSharpEditorConfigOptions editorConfigOptions)
+    {
+        var builder = ImmutableDictionary.CreateBuilder<string, string>();
+
+        AddOptionIfChanged(FormattingOptions2.UseTabs, csharpFallbackOptions, editorConfigOptions.LineFormattingOptions.UseTabs, builder);
+        AddOptionIfChanged(FormattingOptions2.UseTabs, csharpFallbackOptions, editorConfigOptions.LineFormattingOptions.UseTabs, builder);
+        AddOptionIfChanged(FormattingOptions2.TabSize, csharpFallbackOptions, editorConfigOptions.LineFormattingOptions.TabSize, builder);
+        AddOptionIfChanged(FormattingOptions2.IndentationSize, csharpFallbackOptions, editorConfigOptions.LineFormattingOptions.IndentationSize, builder);
+        AddOptionIfChanged(FormattingOptions2.NewLine, csharpFallbackOptions, editorConfigOptions.LineFormattingOptions.NewLine, builder);
+
+        AddOptionIfChanged(ImplementTypeOptionsStorage.InsertionBehavior, csharpFallbackOptions, (ImplementTypeInsertionBehavior)editorConfigOptions.ImplementTypeOptions.InsertionBehavior, builder);
+        AddOptionIfChanged(ImplementTypeOptionsStorage.PropertyGenerationBehavior, csharpFallbackOptions, (ImplementTypePropertyGenerationBehavior)editorConfigOptions.ImplementTypeOptions.PropertyGenerationBehavior, builder);
+
+        return builder.ToImmutable();
+
+        static void AddOptionIfChanged<T>(
+            PerLanguageOption2<T> option,
+            StructuredAnalyzerConfigOptions? analyzerConfigOptions,
+            T value,
+            ImmutableDictionary<string, string>.Builder builder)
+        {
+            var configName = option.Definition.ConfigName;
+            var configValue = option.Definition.Serializer.Serialize(value);
+
+            if (analyzerConfigOptions?.TryGetValue(configName, out var existingValue) == true &&
+                existingValue == configValue)
+            {
+                return;
+            }
+
+            builder.Add(configName, configValue);
+        }
+    }
+}