Remove most direct calls to GetOrParseCSharpSyntaxTree (#12407)

Found while doing #12396, and indeed
the first commit is straight from there, that a few features were
calling `GetOrParseCSharpSyntaxTree`, which always parses the C#
document. Instead, if we call `GetCSharpSyntaxTreeAsync` on the document
snapshot, then in non-cohosting that will still call
`GetOrParseCSharpSyntaxTree`, with the benefit of caching, and in
cohosting it will get the tree from Roslyn, which in almost all cases
I'm sure will have already been realised and cached by Roslyn, and more
importantly will have that cached value shared with way more features
across Roslyn and Razor.

Author: davidwengier

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Debugging/RazorBreakpointSpanEndpoint.cs

@@ -67,7 +67,7 @@ public Uri GetTextDocumentIdentifier(RazorBreakpointSpanParams request)
         }
 
         // Now ask Roslyn to adjust the breakpoint to a valid location in the code
-        var syntaxTree = codeDocument.GetOrParseCSharpSyntaxTree(cancellationToken);
+        var syntaxTree = await documentContext.Snapshot.GetCSharpSyntaxTreeAsync(cancellationToken).ConfigureAwait(false);
         if (!RazorBreakpointSpans.TryGetBreakpointSpan(syntaxTree, projectedIndex, cancellationToken, out var csharpBreakpointSpan))
         {
             return null;

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/Debugging/RazorProximityExpressionsEndpoint.cs

@@ -68,7 +68,7 @@ public Uri GetTextDocumentIdentifier(RazorProximityExpressionsParams request)
         }
 
         // Now ask Roslyn to adjust the breakpoint to a valid location in the code
-        var syntaxTree = codeDocument.GetOrParseCSharpSyntaxTree(cancellationToken);
+        var syntaxTree = await documentContext.Snapshot.GetCSharpSyntaxTreeAsync(cancellationToken).ConfigureAwait(false);
         var expressions = RazorCSharpProximityExpressionResolverService.GetProximityExpressions(syntaxTree, projectedIndex, cancellationToken)?.ToList();
         if (expressions == null)
         {

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/CodeActions/Razor/GenerateMethodCodeActionResolver.cs

@@ -131,7 +131,8 @@ private async Task<WorkspaceEdit> GenerateMethodInCodeBlockAsync(
         if (edits.Length == 3
             && razorClassName is not null
             && (razorNamespace is not null || code.TryGetNamespace(fallbackToRootNamespace: true, out razorNamespace))
-            && GetCSharpClassDeclarationSyntax(code.GetOrParseCSharpSyntaxTree(cancellationToken), razorNamespace, razorClassName) is { } @class)
+            && await documentContext.Snapshot.GetCSharpSyntaxTreeAsync(cancellationToken).ConfigureAwait(false) is { } csharpSyntaxTree
+            && GetCSharpClassDeclarationSyntax(csharpSyntaxTree, razorNamespace, razorClassName) is { } @class)
         {
             // There is no existing @code block. This means that there is no code block source mapping in the generated C# document
             // to place the code, so we cannot utilize the document mapping service and the formatting service.

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Extensions/RazorCodeDocumentExtensions.cs

@@ -10,6 +10,7 @@
 using Microsoft.AspNetCore.Razor.Language.Syntax;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.Razor;
+using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 using Microsoft.CodeAnalysis.Razor.Protocol;
 using Microsoft.CodeAnalysis.Text;
 
@@ -42,6 +43,11 @@ public static SourceText GetHtmlSourceText(this RazorCodeDocument document)
     ///  Retrieves a cached Roslyn <see cref="SyntaxTree"/> from the generated C# document.
     ///  If a tree has not yet been cached, a new one will be parsed and added to the cache.
     /// </summary>
+    /// <remarks>
+    /// If possible, prefer calling <see cref="IDocumentSnapshot.GetCSharpSyntaxTreeAsync(CancellationToken)" />
+    /// because it will either call this method, or in cohosting get the syntax tree from Roslyn, where the cached
+    /// tree can be shared with many more features.
+    /// </remarks>
     public static SyntaxTree GetOrParseCSharpSyntaxTree(this RazorCodeDocument document, CancellationToken cancellationToken)
         => GetCachedData(document).GetOrParseCSharpSyntaxTree(cancellationToken);
 

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/AddUsingsHelper.cs

@@ -18,6 +18,7 @@
 using Microsoft.AspNetCore.Razor.Language.Syntax;
 using Microsoft.AspNetCore.Razor.PooledObjects;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Razor.ProjectSystem;
 using Microsoft.CodeAnalysis.Text;
 using RazorSyntaxNode = Microsoft.AspNetCore.Razor.Language.Syntax.SyntaxNode;
 
@@ -29,7 +30,7 @@ internal static class AddUsingsHelper
 
     private readonly record struct RazorUsingDirective(RazorDirectiveSyntax Node, AddImportChunkGenerator Statement);
 
-    public static async Task<TextEdit[]> GetUsingStatementEditsAsync(RazorCodeDocument codeDocument, SourceText changedCSharpText, CancellationToken cancellationToken)
+    public static async Task<TextEdit[]> GetUsingStatementEditsAsync(IDocumentSnapshot documentSnapshot, SourceText changedCSharpText, CancellationToken cancellationToken)
     {
         // Now that we're done with everything, lets see if there are any using statements to fix up
         // We do this by comparing the original generated C# code, and the changed C# code, and look for a difference
@@ -44,7 +45,8 @@ public static async Task<TextEdit[]> GetUsingStatementEditsAsync(RazorCodeDocume
         // So because of the above, we look for a difference in C# using directive nodes directly from the C# syntax tree, and apply them manually
         // to the Razor document.
 
-        var originalCSharpSyntaxTree = codeDocument.GetOrParseCSharpSyntaxTree(cancellationToken);
+        var codeDocument = await documentSnapshot.GetGeneratedOutputAsync(cancellationToken).ConfigureAwait(false);
+        var originalCSharpSyntaxTree = await documentSnapshot.GetCSharpSyntaxTreeAsync(cancellationToken).ConfigureAwait(false);
         var changedCSharpSyntaxTree = originalCSharpSyntaxTree.WithChangedText(changedCSharpText);
         var oldUsings = await FindUsingDirectiveStringsAsync(originalCSharpSyntaxTree, cancellationToken).ConfigureAwait(false);
         var newUsings = await FindUsingDirectiveStringsAsync(changedCSharpSyntaxTree, cancellationToken).ConfigureAwait(false);

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/CSharpFormatter.cs

@@ -6,7 +6,6 @@
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.AspNetCore.Razor.Language;
 using Microsoft.AspNetCore.Razor.PooledObjects;
 using Microsoft.CodeAnalysis;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
@@ -46,7 +45,7 @@ private static async Task<Dictionary<int, int>> GetCSharpIndentationCoreAsync(
             return [];
         }
 
-        var (indentationMap, syntaxTree) = InitializeIndentationData(context, projectedDocumentLocations, cancellationToken);
+        var (indentationMap, syntaxTree) = await InitializeIndentationDataAsync(context, projectedDocumentLocations, cancellationToken).ConfigureAwait(false);
 
         var root = await syntaxTree.GetRootAsync(cancellationToken).ConfigureAwait(false);
 
@@ -244,7 +243,7 @@ static bool IgnoreInitializerExpression(InitializerExpressionSyntax initializer,
         }
     }
 
-    private static (Dictionary<int, IndentationMapData>, SyntaxTree) InitializeIndentationData(
+    private static async Task<(Dictionary<int, IndentationMapData>, SyntaxTree)> InitializeIndentationDataAsync(
         FormattingContext context,
         IEnumerable<int> projectedDocumentLocations,
         CancellationToken cancellationToken)
@@ -258,8 +257,8 @@ private static (Dictionary<int, IndentationMapData>, SyntaxTree) InitializeInden
 
         using var changes = new PooledArrayBuilder<TextChange>();
 
-        var syntaxTree = context.CodeDocument.GetOrParseCSharpSyntaxTree(cancellationToken);
-        var root = syntaxTree.GetRoot(cancellationToken);
+        var syntaxTree = await context.CurrentSnapshot.GetCSharpSyntaxTreeAsync(cancellationToken).ConfigureAwait(false);
+        var root = await syntaxTree.GetRootAsync(cancellationToken).ConfigureAwait(false);
 
         var previousMarkerOffset = 0;
         foreach (var projectedDocumentIndex in projectedDocumentLocations)

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/FormattingContext.cs

@@ -25,6 +25,7 @@ internal sealed class FormattingContext
     private FormattingContext(
         IDocumentSnapshot originalSnapshot,
         RazorCodeDocument codeDocument,
+        IDocumentSnapshot currentSnapshot,
         RazorFormattingOptions options,
         IFormattingLogger? logger,
         bool automaticallyAddUsings,
@@ -33,6 +34,7 @@ private FormattingContext(
     {
         OriginalSnapshot = originalSnapshot;
         CodeDocument = codeDocument;
+        CurrentSnapshot = currentSnapshot;
         Options = options;
         Logger = logger;
         AutomaticallyAddUsings = automaticallyAddUsings;
@@ -44,6 +46,7 @@ private FormattingContext(
 
     public IDocumentSnapshot OriginalSnapshot { get; }
     public RazorCodeDocument CodeDocument { get; }
+    public IDocumentSnapshot CurrentSnapshot { get; }
     public RazorFormattingOptions Options { get; }
     public IFormattingLogger? Logger { get; }
     public bool AutomaticallyAddUsings { get; }
@@ -232,6 +235,7 @@ public async Task<FormattingContext> WithTextAsync(SourceText changedText, Cance
         var newContext = new FormattingContext(
             OriginalSnapshot,
             codeDocument,
+            currentSnapshot: changedSnapshot,
             Options,
             Logger,
             AutomaticallyAddUsings,
@@ -271,6 +275,7 @@ public static FormattingContext CreateForOnTypeFormatting(
         return new FormattingContext(
             originalSnapshot,
             codeDocument,
+            currentSnapshot: originalSnapshot,
             options,
             logger,
             automaticallyAddUsings,
@@ -287,6 +292,7 @@ public static FormattingContext Create(
         return new FormattingContext(
             originalSnapshot,
             codeDocument,
+            currentSnapshot: originalSnapshot,
             options,
             logger,
             automaticallyAddUsings: false,

src/Razor/src/Microsoft.CodeAnalysis.Razor.Workspaces/Formatting/Passes/CSharpOnTypeFormattingPass.cs

@@ -212,7 +212,7 @@ private static async Task<ImmutableArray<TextChange>> AddUsingStatementEditsIfNe
             // Because we need to parse the C# code twice for this operation, lets do a quick check to see if its even necessary
             if (changes.Any(static e => e.NewText is not null && e.NewText.IndexOf("using") != -1))
             {
-                var usingStatementEdits = await AddUsingsHelper.GetUsingStatementEditsAsync(context.CodeDocument, originalTextWithChanges, cancellationToken).ConfigureAwait(false);
+                var usingStatementEdits = await AddUsingsHelper.GetUsingStatementEditsAsync(context.CurrentSnapshot, originalTextWithChanges, cancellationToken).ConfigureAwait(false);
                 var usingStatementChanges = usingStatementEdits.Select(context.CodeDocument.Source.Text.GetTextChange);
                 finalChanges = [.. usingStatementChanges, .. finalChanges];
             }