[release/5.0] Backport nullability annotations to release/5.0

src/libraries/Common/src/Interop/Windows/HttpApi/Interop.HttpApi.cs

@@ -536,7 +536,7 @@ protected override bool ReleaseHandle()
         [DllImport(Libraries.HttpApi, SetLastError = true)]
         internal static extern unsafe uint HttpReceiveClientCertificate(SafeHandle requestQueueHandle, ulong connectionId, uint flags, byte* pSslClientCertInfo, uint sslClientCertInfoSize, uint* pBytesReceived, NativeOverlapped* pOverlapped);
 
-        internal static readonly string[] HttpVerbs = new string[]
+        internal static readonly string?[] HttpVerbs = new string?[]
         {
             null,
             "Unknown",
@@ -661,9 +661,9 @@ internal static int IndexOfKnownHeader(string headerName)
             }
         }
 
-        private static unsafe string GetKnownHeader(HTTP_REQUEST* request, long fixup, int headerIndex)
+        private static unsafe string? GetKnownHeader(HTTP_REQUEST* request, long fixup, int headerIndex)
         {
-            string header = null;
+            string? header = null;
 
             HTTP_KNOWN_HEADER* pKnownHeader = (&request->Headers.KnownHeaders) + headerIndex;
 
@@ -683,14 +683,14 @@ private static unsafe string GetKnownHeader(HTTP_REQUEST* request, long fixup, i
             return header;
         }
 
-        internal static unsafe string GetKnownHeader(HTTP_REQUEST* request, int headerIndex)
+        internal static unsafe string? GetKnownHeader(HTTP_REQUEST* request, int headerIndex)
         {
             return GetKnownHeader(request, 0, headerIndex);
         }
 
-        private static unsafe string GetVerb(HTTP_REQUEST* request, long fixup)
+        private static unsafe string? GetVerb(HTTP_REQUEST* request, long fixup)
         {
-            string verb = null;
+            string? verb = null;
 
             if ((int)request->Verb > (int)HTTP_VERB.HttpVerbUnknown && (int)request->Verb < (int)HTTP_VERB.HttpVerbMaximum)
             {
@@ -704,12 +704,12 @@ private static unsafe string GetVerb(HTTP_REQUEST* request, long fixup)
             return verb;
         }
 
-        internal static unsafe string GetVerb(HTTP_REQUEST* request)
+        internal static unsafe string? GetVerb(HTTP_REQUEST* request)
         {
             return GetVerb(request, 0);
         }
 
-        internal static unsafe string GetVerb(IntPtr memoryBlob, IntPtr originalAddress)
+        internal static unsafe string? GetVerb(IntPtr memoryBlob, IntPtr originalAddress)
         {
             return GetVerb((HTTP_REQUEST*)memoryBlob.ToPointer(), (byte*)memoryBlob - (byte*)originalAddress);
         }
@@ -834,17 +834,17 @@ internal static unsafe HTTP_VERB GetKnownVerb(IntPtr memoryBlob, IntPtr original
             return verb;
         }
 
-        internal static unsafe IPEndPoint GetRemoteEndPoint(IntPtr memoryBlob, IntPtr originalAddress)
+        internal static unsafe IPEndPoint? GetRemoteEndPoint(IntPtr memoryBlob, IntPtr originalAddress)
         {
-            SocketAddress v4address = new SocketAddress(AddressFamily.InterNetwork, IPv4AddressSize);
-            SocketAddress v6address = new SocketAddress(AddressFamily.InterNetworkV6, IPv6AddressSize);
+            SocketAddress? v4address = new SocketAddress(AddressFamily.InterNetwork, IPv4AddressSize);
+            SocketAddress? v6address = new SocketAddress(AddressFamily.InterNetworkV6, IPv6AddressSize);
 
             byte* pMemoryBlob = (byte*)memoryBlob;
             HTTP_REQUEST* request = (HTTP_REQUEST*)pMemoryBlob;
             IntPtr address = request->Address.pRemoteAddress != null ? (IntPtr)(pMemoryBlob - (byte*)originalAddress + (byte*)request->Address.pRemoteAddress) : IntPtr.Zero;
             CopyOutAddress(address, ref v4address, ref v6address);
 
-            IPEndPoint endpoint = null;
+            IPEndPoint? endpoint = null;
             if (v4address != null)
             {
                 endpoint = new IPEndPoint(IPAddress.Any, IPEndPoint.MinPort).Create(v4address) as IPEndPoint;
@@ -857,17 +857,17 @@ internal static unsafe IPEndPoint GetRemoteEndPoint(IntPtr memoryBlob, IntPtr or
             return endpoint;
         }
 
-        internal static unsafe IPEndPoint GetLocalEndPoint(IntPtr memoryBlob, IntPtr originalAddress)
+        internal static unsafe IPEndPoint? GetLocalEndPoint(IntPtr memoryBlob, IntPtr originalAddress)
         {
-            SocketAddress v4address = new SocketAddress(AddressFamily.InterNetwork, IPv4AddressSize);
-            SocketAddress v6address = new SocketAddress(AddressFamily.InterNetworkV6, IPv6AddressSize);
+            SocketAddress? v4address = new SocketAddress(AddressFamily.InterNetwork, IPv4AddressSize);
+            SocketAddress? v6address = new SocketAddress(AddressFamily.InterNetworkV6, IPv6AddressSize);
 
             byte* pMemoryBlob = (byte*)memoryBlob;
             HTTP_REQUEST* request = (HTTP_REQUEST*)pMemoryBlob;
             IntPtr address = request->Address.pLocalAddress != null ? (IntPtr)(pMemoryBlob - (byte*)originalAddress + (byte*)request->Address.pLocalAddress) : IntPtr.Zero;
             CopyOutAddress(address, ref v4address, ref v6address);
 
-            IPEndPoint endpoint = null;
+            IPEndPoint? endpoint = null;
             if (v4address != null)
             {
                 endpoint = s_any.Create(v4address) as IPEndPoint;
@@ -880,7 +880,7 @@ internal static unsafe IPEndPoint GetLocalEndPoint(IntPtr memoryBlob, IntPtr ori
             return endpoint;
         }
 
-        private static unsafe void CopyOutAddress(IntPtr address, ref SocketAddress v4address, ref SocketAddress v6address)
+        private static unsafe void CopyOutAddress(IntPtr address, ref SocketAddress? v4address, ref SocketAddress? v6address)
         {
             if (address != IntPtr.Zero)
             {
@@ -890,7 +890,7 @@ private static unsafe void CopyOutAddress(IntPtr address, ref SocketAddress v4ad
                     v6address = null;
                     for (int index = 2; index < IPv4AddressSize; index++)
                     {
-                        v4address[index] = ((byte*)address)[index];
+                        v4address![index] = ((byte*)address)[index];
                     }
                     return;
                 }
@@ -899,7 +899,7 @@ private static unsafe void CopyOutAddress(IntPtr address, ref SocketAddress v4ad
                     v4address = null;
                     for (int index = 2; index < IPv6AddressSize; index++)
                     {
-                        v6address[index] = ((byte*)address)[index];
+                        v6address![index] = ((byte*)address)[index];
                     }
                     return;
                 }

src/libraries/Common/src/SkipLocalsInit.cs

@@ -1,5 +1,6 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+#nullable disable
 // Used to indicate to the compiler that the .locals init flag should not be set in method headers.
 [module: System.Runtime.CompilerServices.SkipLocalsInit]

src/libraries/Common/src/System/CSharpHelpers.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+#nullable disable
 using System.Collections.Generic;
 using System.Globalization;
 

src/libraries/Common/src/System/CodeDom/CodeObject.cs

@@ -16,7 +16,7 @@ public class CodeObject
     internal class CodeObject
 #endif
     {
-        private IDictionary _userData;
+        private IDictionary? _userData;
 
         public CodeObject() { }
 

src/libraries/Common/src/System/CodeDom/CodeTypeReference.cs

@@ -28,9 +28,9 @@ public class CodeTypeReference : CodeObject
     internal class CodeTypeReference : CodeObject
 #endif
     {
-        private string _baseType;
+        private string? _baseType;
         private readonly bool _isInterface;
-        private CodeTypeReferenceCollection _typeArguments;
+        private CodeTypeReferenceCollection? _typeArguments;
         private bool _needsFixup;
 
         public CodeTypeReference()
@@ -50,7 +50,7 @@ public CodeTypeReference(Type type)
             if (type.IsArray)
             {
                 ArrayRank = type.GetArrayRank();
-                ArrayElementType = new CodeTypeReference(type.GetElementType());
+                ArrayElementType = new CodeTypeReference(type.GetElementType()!);
                 _baseType = null;
             }
             else
@@ -86,7 +86,7 @@ private void InitializeFromType(Type type)
                 Type currentType = type;
                 while (currentType.IsNested)
                 {
-                    currentType = currentType.DeclaringType;
+                    currentType = currentType.DeclaringType!;
                     _baseType = currentType.Name + "+" + _baseType;
                 }
 
@@ -116,17 +116,17 @@ private void InitializeFromType(Type type)
             }
         }
 
-        private void Initialize(string typeName)
+        private void Initialize(string? typeName)
         {
             Initialize(typeName, Options);
         }
 
-        private void Initialize(string typeName, CodeTypeReferenceOptions options)
+        private void Initialize(string? typeName, CodeTypeReferenceOptions options)
         {
             Options = options;
             if (string.IsNullOrEmpty(typeName))
             {
-                typeName = typeof(void).FullName;
+                typeName = typeof(void).FullName!;
                 _baseType = typeName;
                 ArrayRank = 0;
                 ArrayElementType = null;
@@ -303,7 +303,7 @@ public CodeTypeReference(CodeTypeReference arrayType, int rank)
             ArrayElementType = arrayType;
         }
 
-        public CodeTypeReference ArrayElementType { get; set; }
+        public CodeTypeReference? ArrayElementType { get; set; }
 
         public int ArrayRank { get; set; }
 

src/libraries/Common/src/System/CodeDom/CodeTypeReferenceCollection.cs

@@ -29,7 +29,7 @@ public CodeTypeReferenceCollection(CodeTypeReference[] value)
 
         public CodeTypeReference this[int index]
         {
-            get { return ((CodeTypeReference)(List[index])); }
+            get { return ((CodeTypeReference)(List[index]!)); }
             set { List[index] = value; }
         }
 

src/libraries/Common/src/System/Data/ProviderBase/DbMetaDataFactory.cs

@@ -168,7 +168,7 @@ private DataTable ExecuteCommand(DataRow requestedCollectionRow, string?[]? rest
                     Locale = CultureInfo.InvariantCulture
                 };
 
-                schemaTable = reader.GetSchemaTable();
+                schemaTable = reader.GetSchemaTable()!;
                 foreach (DataRow row in schemaTable.Rows)
                 {
                     resultTable.Columns.Add(row["ColumnName"] as string, (Type)row["DataType"]);

src/libraries/Common/src/System/HexConverter.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+#nullable disable
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 

src/libraries/Common/src/System/Marvin.cs

@@ -1,6 +1,7 @@
 // Licensed to the .NET Foundation under one or more agreements.
 // The .NET Foundation licenses this file to you under the MIT license.
 
+#nullable disable
 using System.Diagnostics;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;

src/libraries/System.Data.Common/ref/System.Data.Common.cs

@@ -863,7 +863,7 @@ public override void Close() { }
         public override System.Type GetProviderSpecificFieldType(int ordinal) { throw null; }
         public override object GetProviderSpecificValue(int ordinal) { throw null; }
         public override int GetProviderSpecificValues(object[] values) { throw null; }
-        public override System.Data.DataTable GetSchemaTable() { throw null; }
+        public override System.Data.DataTable? GetSchemaTable() { throw null; }
         public override string GetString(int ordinal) { throw null; }
         public override object GetValue(int ordinal) { throw null; }
         public override int GetValues(object[] values) { throw null; }
@@ -1247,7 +1247,7 @@ public partial interface IDataReader : System.Data.IDataRecord, System.IDisposab
         bool IsClosed { get; }
         int RecordsAffected { get; }
         void Close();
-        System.Data.DataTable GetSchemaTable();
+        System.Data.DataTable? GetSchemaTable();
         bool NextResult();
         bool Read();
     }
@@ -1948,7 +1948,7 @@ protected override void Dispose(bool disposing) { }
         protected abstract string GetParameterName(int parameterOrdinal);
         protected abstract string GetParameterName(string parameterName);
         protected abstract string GetParameterPlaceholder(int parameterOrdinal);
-        protected virtual System.Data.DataTable GetSchemaTable(System.Data.Common.DbCommand sourceCommand) { throw null; }
+        protected virtual System.Data.DataTable? GetSchemaTable(System.Data.Common.DbCommand sourceCommand) { throw null; }
         public System.Data.Common.DbCommand GetUpdateCommand() { throw null; }
         public System.Data.Common.DbCommand GetUpdateCommand(bool useColumnsForParameterNames) { throw null; }
         protected virtual System.Data.Common.DbCommand InitializeCommand(System.Data.Common.DbCommand? command) { throw null; }
@@ -2169,8 +2169,8 @@ protected virtual void Dispose(bool disposing) { }
         public virtual object GetProviderSpecificValue(int ordinal) { throw null; }
         [System.ComponentModel.EditorBrowsableAttribute(System.ComponentModel.EditorBrowsableState.Never)]
         public virtual int GetProviderSpecificValues(object[] values) { throw null; }
-        public virtual System.Data.DataTable GetSchemaTable() { throw null; }
-        public virtual System.Threading.Tasks.Task<System.Data.DataTable> GetSchemaTableAsync(System.Threading.CancellationToken cancellationToken = default) { throw null; }
+        public virtual System.Data.DataTable? GetSchemaTable() { throw null; }
+        public virtual System.Threading.Tasks.Task<System.Data.DataTable?> GetSchemaTableAsync(System.Threading.CancellationToken cancellationToken = default) { throw null; }
         public virtual System.Threading.Tasks.Task<System.Collections.ObjectModel.ReadOnlyCollection<System.Data.Common.DbColumn>> GetColumnSchemaAsync(System.Threading.CancellationToken cancellationToken = default) { throw null; }
         public virtual System.IO.Stream GetStream(int ordinal) { throw null; }
         public abstract string GetString(int ordinal);
@@ -3536,7 +3536,6 @@ public enum StorageState
         UnmanagedBuffer = 2,
     }
 }
-#nullable disable
 namespace System.Xml
 {
     [System.ObsoleteAttribute("XmlDataDocument class will be removed in a future release.")]
@@ -3546,17 +3545,16 @@ public XmlDataDocument() { }
         public XmlDataDocument(System.Data.DataSet dataset) { }
         public System.Data.DataSet DataSet { get { throw null; } }
         public override System.Xml.XmlNode CloneNode(bool deep) { throw null; }
-        public override System.Xml.XmlElement CreateElement(string prefix, string localName, string namespaceURI) { throw null; }
+        public override System.Xml.XmlElement CreateElement(string? prefix, string localName, string? namespaceURI) { throw null; }
         public override System.Xml.XmlEntityReference CreateEntityReference(string name) { throw null; }
-        protected override System.Xml.XPath.XPathNavigator CreateNavigator(System.Xml.XmlNode node) { throw null; }
-        public override System.Xml.XmlElement GetElementById(string elemId) { throw null; }
+        protected override System.Xml.XPath.XPathNavigator? CreateNavigator(System.Xml.XmlNode node) { throw null; }
+        public override System.Xml.XmlElement? GetElementById(string elemId) { throw null; }
         public System.Xml.XmlElement GetElementFromRow(System.Data.DataRow r) { throw null; }
         public override System.Xml.XmlNodeList GetElementsByTagName(string name) { throw null; }
-        public System.Data.DataRow GetRowFromElement(System.Xml.XmlElement e) { throw null; }
+        public System.Data.DataRow? GetRowFromElement(System.Xml.XmlElement? e) { throw null; }
         public override void Load(System.IO.Stream inStream) { }
         public override void Load(System.IO.TextReader txtReader) { }
         public override void Load(string filename) { }
         public override void Load(System.Xml.XmlReader reader) { }
     }
 }
-#nullable enable

src/libraries/System.Data.Common/src/System/Data/Common/DBCommandBuilder.cs

@@ -646,7 +646,7 @@ private void BuildCache(bool closeConnection, DataRow? dataRow, bool useColumnsF
             ADP.BuildSchemaTableInfoTableNames(srcColumnNames);
         }
 
-        protected virtual DataTable GetSchemaTable(DbCommand sourceCommand)
+        protected virtual DataTable? GetSchemaTable(DbCommand sourceCommand)
         {
             using (IDataReader dataReader = sourceCommand.ExecuteReader(CommandBehavior.SchemaOnly | CommandBehavior.KeyInfo))
             {

src/libraries/System.Data.Common/src/System/Data/Common/DbDataReader.cs

@@ -75,12 +75,13 @@ public virtual ValueTask DisposeAsync()
 
         /// <summary>
         /// Returns a <see cref="DataTable" /> that describes the column metadata of the ><see cref="DbDataReader" />.
+        ///
+        /// Returns <see langword="null" /> if the executed command returned no resultset, or after
+        /// <see cref="NextResult" /> returns <see langword="false" />.
         /// </summary>
         /// <returns>A <see cref="DataTable" /> that describes the column metadata.</returns>
         /// <exception cref="InvalidOperationException">The <see cref="DbDataReader" /> is closed.</exception>
-        /// <exception cref="IndexOutOfRangeException">The column index is out of range.</exception>
-        /// <exception cref="NotSupportedException">.NET Core only: This member is not supported.</exception>
-        public virtual DataTable GetSchemaTable()
+        public virtual DataTable? GetSchemaTable()
         {
             throw new NotSupportedException();
         }
@@ -97,11 +98,11 @@ public virtual DataTable GetSchemaTable()
         /// </summary>
         /// <param name="cancellationToken">The cancellation instruction.</param>
         /// <returns>A task representing the asynchronous operation.</returns>
-        public virtual Task<DataTable> GetSchemaTableAsync(CancellationToken cancellationToken = default)
+        public virtual Task<DataTable?> GetSchemaTableAsync(CancellationToken cancellationToken = default)
         {
             if (cancellationToken.IsCancellationRequested)
             {
-                return Task.FromCanceled<DataTable>(cancellationToken);
+                return Task.FromCanceled<DataTable?>(cancellationToken);
             }
 
             try
@@ -110,7 +111,7 @@ public virtual Task<DataTable> GetSchemaTableAsync(CancellationToken cancellatio
             }
             catch (Exception e)
             {
-                return Task.FromException<DataTable>(e);
+                return Task.FromException<DataTable?>(e);
             }
         }
 

src/libraries/System.Data.Common/src/System/Data/Common/DbDataReaderExtensions.cs

@@ -73,12 +73,15 @@ public static bool CanGetColumnSchema(this DbDataReader reader)
         private static ReadOnlyCollection<DbColumn> GetColumnSchemaCompatibility(DbDataReader reader)
         {
             var columnSchema = new List<DbColumn>();
-            DataTable schemaTable = reader.GetSchemaTable();
-            DataColumnCollection schemaTableColumns = schemaTable.Columns;
-            foreach (DataRow row in schemaTable.Rows)
+            DataTable? schemaTable = reader.GetSchemaTable();
+            if (schemaTable != null)
             {
-                Debug.Assert(row != null);
-                columnSchema.Add(new DataRowDbColumn(row, schemaTableColumns));
+                DataColumnCollection schemaTableColumns = schemaTable.Columns;
+                foreach (DataRow row in schemaTable.Rows)
+                {
+                    Debug.Assert(row != null);
+                    columnSchema.Add(new DataRowDbColumn(row, schemaTableColumns));
+                }
             }
             return new ReadOnlyCollection<DbColumn>(columnSchema);
         }