Latest nullability updates

- handle Microsoft.Extensions.FileProviders.Abstractions nullability annotations (dotnet/runtime#57405)
- handle Microsoft.Extensions.FileProviders.Physical nullability annotations (dotnet/runtime#57409)
- !fixup! improve `HttpConnectionDispatcher.GetConnectionToken(...)` and its use

src/FileProviders/Embedded/src/Manifest/ManifestDirectoryInfo.cs

@@ -25,7 +25,7 @@ public ManifestDirectoryInfo(ManifestDirectory directory, DateTimeOffset lastMod
 
         public string? PhysicalPath => null;
 
-        public string? Name => Directory.Name;
+        public string Name => Directory.Name;
 
         public DateTimeOffset LastModified { get; }
 

src/FileProviders/Embedded/src/Manifest/ManifestFileInfo.cs

@@ -38,7 +38,7 @@ public ManifestFileInfo(Assembly assembly, ManifestFile file, DateTimeOffset las
 
         public string? PhysicalPath => null;
 
-        public string? Name => ManifestFile.Name;
+        public string Name => ManifestFile.Name;
 
         public DateTimeOffset LastModified { get; }
 

src/Middleware/StaticFiles/src/DefaultFilesMiddleware.cs

@@ -67,7 +67,8 @@ public Task Invoke(HttpContext context)
                 && Helpers.IsGetOrHeadMethod(context.Request.Method)
                 && Helpers.TryMatchPath(context, _matchUrl, forDirectory: true, subpath: out var subpath))
             {
-                var dirContents = _fileProvider.GetDirectoryContents(subpath.Value);
+                // TryMatchPath will not output an empty subpath when it returns true.
+                var dirContents = _fileProvider.GetDirectoryContents(subpath.Value!);
                 if (dirContents.Exists)
                 {
                     // Check if any of our default files exist.

src/Middleware/StaticFiles/src/DirectoryBrowserMiddleware.cs

@@ -101,7 +101,8 @@ public Task Invoke(HttpContext context)
 
         private bool TryGetDirectoryInfo(PathString subpath, out IDirectoryContents contents)
         {
-            contents = _fileProvider.GetDirectoryContents(subpath.Value);
+            // TryMatchPath will not output an empty subpath when it returns true. This is called only in that case.
+            contents = _fileProvider.GetDirectoryContents(subpath.Value!);
             return contents.Exists;
         }
     }

src/Middleware/StaticFiles/src/StaticFileContext.cs

@@ -1,11 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
-using System;
 using System.Diagnostics;
-using System.IO;
-using System.Linq;
-using System.Threading.Tasks;
 using Microsoft.AspNetCore.Builder;
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Http.Features;
@@ -47,6 +43,11 @@ internal struct StaticFileContext
 
         public StaticFileContext(HttpContext context, StaticFileOptions options, ILogger logger, IFileProvider fileProvider, string? contentType, PathString subPath)
         {
+            if (!subPath.HasValue)
+            {
+                throw new ArgumentNullException(nameof(subPath));
+            }
+
             _context = context;
             _options = options;
             _request = context.Request;
@@ -109,11 +110,11 @@ private set
 
         public string SubPath => _subPath.Value!;
 
-        public string PhysicalPath => _fileInfo.PhysicalPath;
+        public string PhysicalPath => _fileInfo.PhysicalPath ?? string.Empty;
 
         public bool LookupFileInfo()
         {
-            _fileInfo = _fileProvider.GetFileInfo(_subPath.Value);
+            _fileInfo = _fileProvider.GetFileInfo(SubPath);
             if (_fileInfo.Exists)
             {
                 _length = _fileInfo.Length;
@@ -264,7 +265,7 @@ public void ApplyResponseHeaders(int statusCode)
                 _response.ContentLength = _length;
             }
 
-            _options.OnPrepareResponse(new StaticFileResponseContext(_context, _fileInfo!));
+            _options.OnPrepareResponse(new StaticFileResponseContext(_context, _fileInfo));
         }
 
         public PreconditionState GetPreconditionState()

src/Mvc/Mvc.Razor.RuntimeCompilation/src/FileProviderRazorProjectItem.cs

@@ -63,7 +63,7 @@ public FileProviderRazorProjectItem(IFileInfo fileInfo, string basePath, string
         public override bool Exists => FileInfo.Exists;
 
         /// <inheritdoc/>
-        public override string PhysicalPath => FileInfo.PhysicalPath;
+        public override string PhysicalPath => FileInfo.PhysicalPath ?? string.Empty;
 
         /// <inheritdoc/>
         public override string? RelativePhysicalPath

src/Shared/MediaType/ReadOnlyMediaTypeHeaderValue.cs

@@ -25,7 +25,7 @@ public ReadOnlyMediaTypeHeaderValue(string mediaType)
     /// </summary>
     /// <param name="mediaType">The <see cref="StringSegment"/> with the media type.</param>
     public ReadOnlyMediaTypeHeaderValue(StringSegment mediaType)
-        : this(mediaType.Buffer, mediaType.Offset, mediaType.Length)
+        : this(mediaType.Buffer ?? string.Empty, mediaType.Offset, mediaType.Length)
     {
     }
 
@@ -146,7 +146,7 @@ private static bool TryGetSuffixLength(StringSegment subType, out int suffixLeng
         var startPos = subType.Offset + subType.Length - 1;
         for (var currentPos = startPos; currentPos >= subType.Offset; currentPos--)
         {
-            if (subType.Buffer[currentPos] == '+')
+            if (subType.Buffer![currentPos] == '+')
             {
                 suffixLength = startPos - currentPos;
                 return true;
@@ -357,7 +357,7 @@ public bool TryGetLastParameter(StringSegment parameterName, out StringSegment p
             // charset.Value might be an invalid encoding name as in charset=invalid.
             // For that reason, we catch the exception thrown by Encoding.GetEncoding
             // and return null instead.
-            return charset.HasValue ? Encoding.GetEncoding(charset.Value) : null;
+            return charset.HasValue ? Encoding.GetEncoding(charset.Value!) : null;
         }
         catch (Exception)
         {

src/Shared/StaticWebAssets/StaticWebAssetsFileProvider.cs

@@ -294,7 +294,7 @@ public StaticWebAssetsFileInfo(string name, IFileInfo source)
 
             public long Length => _source.Length;
 
-            public string PhysicalPath => _source.PhysicalPath;
+            public string PhysicalPath => _source.PhysicalPath ?? string.Empty;
 
             public DateTimeOffset LastModified => _source.LastModified;
 

src/SignalR/common/Http.Connections/src/Internal/HttpConnectionDispatcher.cs

@@ -65,7 +65,7 @@ public async Task ExecuteAsync(HttpContext context, HttpConnectionDispatcherOpti
 
             HttpConnectionContext? connectionContext = null;
             var connectionToken = GetConnectionToken(context);
-            if (connectionToken != null)
+            if (!StringValues.IsNullOrEmpty(connectionToken))
             {
                 _manager.TryGetConnection(connectionToken, out connectionContext);
             }
@@ -381,7 +381,7 @@ private static bool ServerHasWebSockets(IFeatureCollection features)
             return features.Get<IHttpWebSocketFeature>() != null;
         }
 
-        private static string GetConnectionToken(HttpContext context) => context.Request.Query["id"].ToString();
+        private static StringValues GetConnectionToken(HttpContext context) => context.Request.Query["id"];
 
         private async Task ProcessSend(HttpContext context, HttpConnectionDispatcherOptions options)
         {