Don't throw if we get an old/bad Inlay Hint request

src/Razor/src/Microsoft.AspNetCore.Razor.LanguageServer/InlayHints/InlayHintService.cs

@@ -29,6 +29,16 @@ internal sealed class InlayHintService(IDocumentMappingService documentMappingSe
 
         var span = range.ToLinePositionSpan();
 
+        cancellationToken.ThrowIfCancellationRequested();
+
+        // Sometimes the client sends us a request that doesn't match the file contents. Could be a bug with old requests
+        // not being cancelled, but no harm in being defensive
+        if (!codeDocument.Source.Text.TryGetAbsoluteIndex(span.Start, out var startIndex) ||
+            !codeDocument.Source.Text.TryGetAbsoluteIndex(span.End, out var endIndex))
+        {
+            return null;
+        }
+
         // We are given a range by the client, but our mapping only succeeds if the start and end of the range can both be mapped
         // to C#. Since that doesn't logically match what we want from inlay hints, we instead get the minimum range of mappable
         // C# to get hints for. We'll filter that later, to remove the sections that can't be mapped back.

src/Razor/src/Microsoft.CodeAnalysis.Remote.Razor/InlayHints/RemoteInlayHintService.cs

@@ -41,6 +41,16 @@ protected override IRemoteInlayHintService CreateService(in ServiceArgs args)
 
         var span = inlayHintParams.Range.ToLinePositionSpan();
 
+        cancellationToken.ThrowIfCancellationRequested();
+
+        // Sometimes the client sends us a request that doesn't match the file contents. Could be a bug with old requests
+        // not being cancelled, but no harm in being defensive
+        if (!codeDocument.Source.Text.TryGetAbsoluteIndex(span.Start, out var startIndex) ||
+            !codeDocument.Source.Text.TryGetAbsoluteIndex(span.End, out var endIndex))
+        {
+            return null;
+        }
+
         // We are given a range by the client, but our mapping only succeeds if the start and end of the range can both be mapped
         // to C#. Since that doesn't logically match what we want from inlay hints, we instead get the minimum range of mappable
         // C# to get hints for. We'll filter that later, to remove the sections that can't be mapped back.

src/Razor/test/Microsoft.AspNetCore.Razor.LanguageServer.Test/InlayHints/InlayHintEndpointTest.cs

@@ -73,8 +73,8 @@ public Task InlayHints_ComponentAttributes()
 
                 """,
             toolTipMap: new Dictionary<string, string>
-                {
-                },
+            {
+            },
             output: """
 
                 <div>
@@ -85,6 +85,42 @@ public Task InlayHints_ComponentAttributes()
 
                 """);
 
+    [Theory]
+    [InlineData(0, 0, 0, 20)]
+    [InlineData(0, 0, 2, 0)]
+    [InlineData(2, 0, 4, 0)]
+    public async Task InlayHints_InvalidRange(int startLine, int starChar, int endLine, int endChar)
+    {
+        var input = """
+            <div></div>
+            """;
+        var razorFilePath = "C:/path/to/file.razor";
+        var codeDocument = CreateCodeDocument(input, filePath: razorFilePath);
+
+        var languageServer = await CreateLanguageServerAsync(codeDocument, razorFilePath);
+
+        var service = new InlayHintService(DocumentMappingService);
+
+        var endpoint = new InlayHintEndpoint(service, languageServer);
+
+        var request = new InlayHintParams()
+        {
+            TextDocument = new VSTextDocumentIdentifier
+            {
+                Uri = new Uri(razorFilePath)
+            },
+            Range = VsLspFactory.CreateRange(startLine, starChar, endLine, endChar)
+        };
+        Assert.True(DocumentContextFactory.TryCreate(request.TextDocument, out var documentContext));
+        var requestContext = CreateRazorRequestContext(documentContext);
+
+        // Act
+        var hints = await endpoint.HandleRequestAsync(request, requestContext, DisposalToken);
+
+        // Assert
+        Assert.Null(hints);
+    }
+
     private async Task VerifyInlayHintsAsync(string input, Dictionary<string, string> toolTipMap, string output)
     {
         TestFileMarkupParser.GetSpans(input, out input, out ImmutableDictionary<string, ImmutableArray<TextSpan>> spansDict);

src/Razor/test/Microsoft.VisualStudio.LanguageServices.Razor.Test/Cohost/CohostInlayHintEndpointTest.cs

@@ -128,6 +128,30 @@ public Task InlayHints_ComponentAttributes()
 
                 """);
 
+    [Theory]
+    [InlineData(0, 0, 0, 20)]
+    [InlineData(0, 0, 2, 0)]
+    [InlineData(2, 0, 4, 0)]
+    public async Task InlayHints_InvalidRange(int startLine, int starChar, int endLine, int endChar)
+    {
+        var input = """
+            <div></div>
+            """;
+        var document = await CreateProjectAndRazorDocumentAsync(input);
+        var endpoint = new CohostInlayHintEndpoint(RemoteServiceInvoker);
+
+        var request = new InlayHintParams()
+        {
+            TextDocument = new TextDocumentIdentifier() { Uri = document.CreateUri() },
+            Range = RoslynLspFactory.CreateRange(startLine, starChar, endLine, endChar)
+        };
+
+        var hints = await endpoint.GetTestAccessor().HandleRequestAsync(request, document, displayAllOverride: false, DisposalToken);
+
+        // Assert
+        Assert.Null(hints);
+    }
+
     private async Task VerifyInlayHintsAsync(string input, Dictionary<string, string> toolTipMap, string output, bool displayAllOverride = false)
     {
         TestFileMarkupParser.GetSpans(input, out input, out ImmutableDictionary<string, ImmutableArray<TextSpan>> spansDict);