Fix/remove TODO-NULLABLEs (#44300)

krwq · web-flow · commit c871e237b00d · 2020-11-09T13:07:15.000+01:00
* Fix/remove TODO-NULLABLEs

* remove redundant !

* apply Jozkee's feedback

* address feedback
diff --git a/src/libraries/System.ComponentModel.Annotations/src/System/ComponentModel/DataAnnotations/CompareAttribute.cs b/src/libraries/System.ComponentModel.Annotations/src/System/ComponentModel/DataAnnotations/CompareAttribute.cs
@@ -60,8 +60,6 @@ public override string FormatErrorMessage(string name) =>
             var display = attributes.OfType<DisplayAttribute>().FirstOrDefault();
             if (display != null)
             {
-                // TODO-NULLABLE: This will return null if [DisplayName] is specified but no Name has been defined - probably a bug.
-                // Should fall back to OtherProperty in this case instead.
                 return display.GetName();
             }
 
diff --git a/src/libraries/System.ComponentModel.Annotations/src/System/ComponentModel/DataAnnotations/ValidationAttribute.cs b/src/libraries/System.ComponentModel.Annotations/src/System/ComponentModel/DataAnnotations/ValidationAttribute.cs
@@ -273,8 +273,6 @@ private void SetResourceAccessorByPropertyLookup()
                                                     _errorMessageResourceType.FullName));
             }
 
-
-            // TODO-NULLABLE: If the user-provided resource returns null, an ArgumentNullException is thrown - should probably throw a better exception
             _errorMessageResourceAccessor = () => (string)property.GetValue(null, null)!;
         }
 
diff --git a/src/libraries/System.ComponentModel.Annotations/src/System/ComponentModel/DataAnnotations/Validator.cs b/src/libraries/System.ComponentModel.Annotations/src/System/ComponentModel/DataAnnotations/Validator.cs
@@ -137,7 +137,6 @@ public static bool TryValidateObject(object instance, ValidationContext validati
                 throw new ArgumentNullException(nameof(instance));
             }
 
-            // TODO-NULLABLE: null validationContext isn't supported (GetObjectValidationErrors will throw), remove that check
             if (validationContext != null && instance != validationContext.ObjectInstance)
             {
                 throw new ArgumentException(SR.Validator_InstanceMustMatchValidationContextInstance, nameof(instance));
diff --git a/src/libraries/System.Data.Odbc/src/System/Data/Odbc/OdbcConnectionOpen.cs b/src/libraries/System.Data.Odbc/src/System/Data/Odbc/OdbcConnectionOpen.cs
@@ -32,7 +32,7 @@ public override string ServerVersion
         {
             get
             {
-                // TODO-NULLABLE: This seems like it returns null if the connection is open, whereas the docs say it should throw
+                // https://github.com/dotnet/runtime/issues/44289: This seems like it returns null if the connection is open, whereas the docs say it should throw
                 // InvalidOperationException
                 return OuterConnection.Open_GetServerVersion()!;
             }
diff --git a/src/libraries/System.Data.OleDb/src/ColumnBinding.cs b/src/libraries/System.Data.OleDb/src/ColumnBinding.cs
@@ -948,8 +948,7 @@ internal OleDbDataReader Value_HCHAPTER()
             Debug.Assert(NativeDBType.HCHAPTER == DbType, "Value_HCHAPTER");
             Debug.Assert(DBStatus.S_OK == StatusValue(), "Value_HCHAPTER");
 
-            // TODO-NULLABLE: This shouldn't return null
-            return DataReader().ResetChapter(IndexForAccessor, IndexWithinAccessor, RowBinding, ValueOffset)!;
+            return DataReader().ResetChapter(IndexForAccessor, IndexWithinAccessor, RowBinding, ValueOffset);
         }
 
         private sbyte Value_I1()
diff --git a/src/libraries/System.Data.OleDb/src/OleDbCommand.cs b/src/libraries/System.Data.OleDb/src/OleDbCommand.cs
@@ -818,7 +818,6 @@ private int ExecuteCommandText(out object executeResult)
             RuntimeHelpers.PrepareConstrainedRegions();
             try
             {
-                // TODO-NULLABLE: Code below seems to assume that bindings will always be non-null
                 if (null != bindings)
                 { // parameters may be suppressed
                     rowbinding = bindings.RowBinding();
diff --git a/src/libraries/System.Data.OleDb/src/OleDbConnectionFactory.cs b/src/libraries/System.Data.OleDb/src/OleDbConnectionFactory.cs
@@ -33,8 +33,7 @@ public override DbProviderFactory ProviderFactory
 
         protected override DbConnectionInternal CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, object poolGroupProviderInfo, DbConnectionPool? pool, DbConnection? owningObject)
         {
-            // TODO-NULLABLE: owningObject may actually be null (see DbConnectionPool.CreateObject), in which case this will throw...
-            DbConnectionInternal result = new OleDbConnectionInternal((OleDbConnectionString)options, (OleDbConnection)owningObject!);
+            DbConnectionInternal result = new OleDbConnectionInternal((OleDbConnectionString)options, (OleDbConnection?)owningObject);
             return result;
         }
 
diff --git a/src/libraries/System.Data.OleDb/src/OleDbConnectionInternal.cs b/src/libraries/System.Data.OleDb/src/OleDbConnectionInternal.cs
@@ -385,7 +385,7 @@ internal void EnlistTransactionInternal(SysTx.Transaction? transaction)
             using (IDBInfoWrapper wrapper = IDBInfo())
             {
                 UnsafeNativeMethods.IDBInfo dbInfo = wrapper.Value;
-                // TODO-NULLABLE: check may not be necessary (and thus method may return non-nullable)
+                // https://github.com/dotnet/runtime/issues/44288: check may not be necessary (and thus method may return non-nullable)
                 if (null == dbInfo)
                 {
                     return null;
diff --git a/src/libraries/System.Data.OleDb/src/OleDbDataReader.cs b/src/libraries/System.Data.OleDb/src/OleDbDataReader.cs
@@ -951,22 +951,23 @@ protected override DbDataReader GetDbDataReader(int ordinal)
             return GetData(ordinal);
         }
 
-        internal OleDbDataReader? ResetChapter(int bindingIndex, int index, RowBinding rowbinding, int valueOffset)
+        internal OleDbDataReader ResetChapter(int bindingIndex, int index, RowBinding rowbinding, int valueOffset)
         {
             return GetDataForReader(_metadata![bindingIndex + index].ordinal, rowbinding, valueOffset);
         }
 
-        private OleDbDataReader? GetDataForReader(IntPtr ordinal, RowBinding rowbinding, int valueOffset)
+        private OleDbDataReader GetDataForReader(IntPtr ordinal, RowBinding rowbinding, int valueOffset)
         {
             UnsafeNativeMethods.IRowsetInfo rowsetInfo = IRowsetInfo();
             UnsafeNativeMethods.IRowset? result;
             OleDbHResult hr;
             hr = rowsetInfo.GetReferencedRowset((IntPtr)ordinal, ref ODB.IID_IRowset, out result);
 
             ProcessResults(hr);
+            // Per docs result can be null only when hr is DB_E_NOTAREFERENCECOLUMN which in most of the cases will cause the exception in ProcessResult
 
             OleDbDataReader? reader = null;
-            // TODO: Not sure if GetReferenceRowset above actually returns null, calling code seems to assume it doesn't
+
             if (null != result)
             {
                 // only when the first datareader is closed will the connection close
@@ -983,6 +984,7 @@ protected override DbDataReader GetDbDataReader(int ordinal)
                     _connection.AddWeakReference(reader, OleDbReferenceCollection.DataReaderTag);
                 }
             }
+
             return reader;
         }
 
@@ -1022,8 +1024,9 @@ public override Type GetFieldType(int index)
         {
             if (null != _metadata)
             {
-                // TODO-NULLABLE: Should throw if null (empty), though it probably doesn't happen
-                return _metadata[index].type.dataType!;
+                Type? fieldType = _metadata[index].type.dataType;
+                Debug.Assert(fieldType != null);
+                return fieldType;
             }
             throw ADP.DataReaderNoData();
         }
@@ -2273,7 +2276,6 @@ internal void DumpToSchemaTable(UnsafeNativeMethods.IRowset? rowset)
             using (OleDbDataReader dataReader = new OleDbDataReader(_connection, _command, int.MinValue, 0))
             {
                 dataReader.InitializeIRowset(rowset, ChapterHandle.DB_NULL_HCHAPTER, IntPtr.Zero);
-                // TODO-NULLABLE: BuildSchemaTableInfo asserts that rowset isn't null, but doesn't do anything with it
                 dataReader.BuildSchemaTableInfo(rowset!, true, false);
 
                 hiddenColumns = GetPropertyValue(ODB.DBPROP_HIDDENCOLUMNS);
diff --git a/src/libraries/System.Data.OleDb/src/UnsafeNativeMethods.cs b/src/libraries/System.Data.OleDb/src/UnsafeNativeMethods.cs
@@ -723,7 +723,7 @@ System.Data.OleDb.OleDbHResult GetProperties(
             System.Data.OleDb.OleDbHResult GetReferencedRowset(
                 [In] IntPtr iOrdinal,
                 [In] ref Guid riid,
-                [Out, MarshalAs(UnmanagedType.Interface)] out IRowset ppRowset);
+                [Out, MarshalAs(UnmanagedType.Interface)] out IRowset? ppRowset);
 
             //[PreserveSig]
             //int GetSpecification(/*deleted parameter signature*/);
diff --git a/src/libraries/System.Linq/src/System/Linq/Select.SpeedOpt.cs b/src/libraries/System.Linq/src/System/Linq/Select.SpeedOpt.cs
@@ -11,7 +11,7 @@ namespace System.Linq
     public static partial class Enumerable
     {
         static partial void CreateSelectIPartitionIterator<TResult, TSource>(
-            Func<TSource, TResult> selector, IPartition<TSource> partition, ref IEnumerable<TResult>? result) // TODO-NULLABLE: https://github.com/dotnet/roslyn/issues/38327
+            Func<TSource, TResult> selector, IPartition<TSource> partition, ref IEnumerable<TResult>? result)
         {
             result = partition is EmptyPartition<TSource> ?
                 EmptyPartition<TResult>.Instance :
diff --git a/src/libraries/System.Private.Xml.Linq/src/System/Xml/Linq/Extensions.cs b/src/libraries/System.Private.Xml.Linq/src/System/Xml/Linq/Extensions.cs
@@ -271,15 +271,13 @@ public static IEnumerable<XElement> Elements<T>(this IEnumerable<T?> source, XNa
         /// for each <see cref="XElement"/> in this <see cref="IEnumerable"/> of <see cref="XElement"/>.
         /// in document order
         /// </returns>
-        public static IEnumerable<T> InDocumentOrder<T>(this IEnumerable<T> source) where T : XNode
+        public static IEnumerable<T> InDocumentOrder<T>(this IEnumerable<T> source) where T : XNode?
         {
             if (source == null) throw new ArgumentNullException(nameof(source));
             return DocumentOrderIterator<T>(source);
         }
 
-        // TODO-NULLABLE: Consider changing to T? instead.
-        // If we do it, we will also need to change XNodeDocumentOrderComparer to implement IComparer<XNode?> instead.
-        private static IEnumerable<T> DocumentOrderIterator<T>(IEnumerable<T> source) where T : XNode
+        private static IEnumerable<T> DocumentOrderIterator<T>(IEnumerable<T> source) where T : XNode?
         {
             int count;
             T[] items = EnumerableHelpers.ToArray(source, out count);
diff --git a/src/libraries/System.Private.Xml.Linq/src/System/Xml/Linq/XContainer.cs b/src/libraries/System.Private.Xml.Linq/src/System/Xml/Linq/XContainer.cs
@@ -1041,8 +1041,7 @@ public async ValueTask<bool> ReadContentFromAsync(XContainer rootContainer, XmlR
             public bool ReadContentFrom(XContainer rootContainer, XmlReader r, LoadOptions o)
             {
                 XNode? newNode = null;
-                // TODO-NULLABLE: Consider changing XmlReader.BaseURI to non-nullable.
-                string baseUri = r.BaseURI!;
+                string baseUri = r.BaseURI;
 
                 switch (r.NodeType)
                 {
diff --git a/src/libraries/System.Private.Xml.Linq/src/System/Xml/Linq/XDocumentType.cs b/src/libraries/System.Private.Xml.Linq/src/System/Xml/Linq/XDocumentType.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.
 
+using System.Diagnostics.CodeAnalysis;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -19,12 +20,12 @@ public class XDocumentType : XNode
         /// <summary>
         /// Initializes an empty instance of the <see cref="XDocumentType"/> class.
         /// </summary>
-        public XDocumentType(string name, string? publicId, string? systemId, string internalSubset)
+        public XDocumentType(string name, string? publicId, string? systemId, string? internalSubset)
         {
             _name = XmlConvert.VerifyName(name);
             _publicId = publicId;
             _systemId = systemId;
-            _internalSubset = internalSubset;
+            _internalSubset = internalSubset ?? string.Empty;
         }
 
         /// <summary>
@@ -53,20 +54,17 @@ internal XDocumentType(XmlReader r)
         /// <summary>
         /// Gets or sets the internal subset for this Document Type Definition (DTD).
         /// </summary>
+        [AllowNull]
         public string InternalSubset
         {
             get
             {
-                // TODO-NULLABLE: As per documentation, this should return string.Empty.
-                // Should we check for null here?
-                // This is also referenced by XNodeReader.Value which overrides XmlReader.Value, which is non-nullable.
-                // There is one case that passes a nullable parameter (XNodeBuilder.WriteDocType), currently we are just asserting that the nullable parameter does not receive null.
                 return _internalSubset;
             }
             set
             {
                 bool notify = NotifyChanging(this, XObjectChangeEventArgs.Value);
-                _internalSubset = value;
+                _internalSubset = value ?? string.Empty;
                 if (notify) NotifyChanged(this, XObjectChangeEventArgs.Value);
             }
         }
@@ -184,7 +182,7 @@ internal override int GetDeepHashCode()
             return _name.GetHashCode() ^
                 (_publicId != null ? _publicId.GetHashCode() : 0) ^
                 (_systemId != null ? _systemId.GetHashCode() : 0) ^
-                (_internalSubset != null ? _internalSubset.GetHashCode() : 0);
+                _internalSubset.GetHashCode();
         }
     }
 }
diff --git a/src/libraries/System.Private.Xml.Linq/src/System/Xml/Linq/XNodeBuilder.cs b/src/libraries/System.Private.Xml.Linq/src/System/Xml/Linq/XNodeBuilder.cs
@@ -83,7 +83,6 @@ public override void WriteComment(string? text)
 
         public override void WriteDocType(string name, string? pubid, string? sysid, string? subset)
         {
-            Debug.Assert(subset != null);
             AddNode(new XDocumentType(name, pubid, sysid, subset));
         }
 
diff --git a/src/libraries/System.Private.Xml.Linq/src/System/Xml/Linq/XNodeDocumentOrderComparer.cs b/src/libraries/System.Private.Xml.Linq/src/System/Xml/Linq/XNodeDocumentOrderComparer.cs
@@ -13,7 +13,7 @@ namespace System.Xml.Linq
     /// </summary>
     public sealed class XNodeDocumentOrderComparer :
         IComparer,
-        IComparer<XNode>
+        IComparer<XNode?>
     {
         /// <summary>
         /// Compares two nodes to determine their relative XML document order.
diff --git a/src/libraries/System.Private.Xml.Linq/src/System/Xml/Linq/XNodeReader.cs b/src/libraries/System.Private.Xml.Linq/src/System/Xml/Linq/XNodeReader.cs
@@ -552,9 +552,11 @@ public override void Close()
             return null;
         }
 
-        // TODO-NULLABLE: decide if base signature should be switched to return string?
         public override string GetAttribute(int index)
         {
+            // https://github.com/dotnet/runtime/issues/44287
+            //     We should replace returning null with ArgumentOutOfRangeException
+            //     In case of not interactive state likely we should throw InvalidOperationException
             if (!IsInteractive)
             {
                 return null!;
diff --git a/src/libraries/System.Private.Xml.Linq/src/System/Xml/XPath/XNodeNavigator.cs b/src/libraries/System.Private.Xml.Linq/src/System/Xml/XPath/XNodeNavigator.cs
@@ -462,11 +462,12 @@ public override bool MoveToNamespace(string localName)
                 {
                     return false; // backcompat
                 }
-                // TODO-NULLABLE: Unnecessary null check?
+
                 if (localName != null && localName.Length == 0)
                 {
                     localName = "xmlns"; // backcompat
                 }
+
                 XAttribute? a = GetFirstNamespaceDeclarationGlobal(e);
                 while (a != null)
                 {
@@ -478,6 +479,7 @@ public override bool MoveToNamespace(string localName)
                     }
                     a = GetNextNamespaceDeclarationGlobal(a);
                 }
+
                 if (localName == "xml")
                 {
                     _source = GetXmlNamespaceDeclaration();
diff --git a/src/libraries/System.Xml.XDocument/ref/System.Xml.XDocument.cs b/src/libraries/System.Xml.XDocument/ref/System.Xml.XDocument.cs
@@ -22,7 +22,7 @@ public static partial class Extensions
         public static System.Collections.Generic.IEnumerable<System.Xml.Linq.XElement> Descendants<T>(this System.Collections.Generic.IEnumerable<T?> source, System.Xml.Linq.XName? name) where T : System.Xml.Linq.XContainer { throw null; }
         public static System.Collections.Generic.IEnumerable<System.Xml.Linq.XElement> Elements<T>(this System.Collections.Generic.IEnumerable<T?> source) where T : System.Xml.Linq.XContainer { throw null; }
         public static System.Collections.Generic.IEnumerable<System.Xml.Linq.XElement> Elements<T>(this System.Collections.Generic.IEnumerable<T?> source, System.Xml.Linq.XName? name) where T : System.Xml.Linq.XContainer { throw null; }
-        public static System.Collections.Generic.IEnumerable<T> InDocumentOrder<T>(this System.Collections.Generic.IEnumerable<T> source) where T : System.Xml.Linq.XNode { throw null; }
+        public static System.Collections.Generic.IEnumerable<T> InDocumentOrder<T>(this System.Collections.Generic.IEnumerable<T> source) where T : System.Xml.Linq.XNode? { throw null; }
         public static System.Collections.Generic.IEnumerable<System.Xml.Linq.XNode> Nodes<T>(this System.Collections.Generic.IEnumerable<T?> source) where T : System.Xml.Linq.XContainer { throw null; }
         public static void Remove(this System.Collections.Generic.IEnumerable<System.Xml.Linq.XAttribute?> source) { }
         public static void Remove<T>(this System.Collections.Generic.IEnumerable<T?> source) where T : System.Xml.Linq.XNode { }
@@ -212,8 +212,9 @@ public override void WriteTo(System.Xml.XmlWriter writer) { }
     }
     public partial class XDocumentType : System.Xml.Linq.XNode
     {
-        public XDocumentType(string name, string? publicId, string? systemId, string internalSubset) { }
+        public XDocumentType(string name, string? publicId, string? systemId, string? internalSubset) { }
         public XDocumentType(System.Xml.Linq.XDocumentType other) { }
+        [System.Diagnostics.CodeAnalysis.AllowNull]
         public string InternalSubset { get { throw null; } set { } }
         public string Name { get { throw null; } set { } }
         public override System.Xml.XmlNodeType NodeType { get { throw null; } }
@@ -425,7 +426,7 @@ public void ReplaceWith(params object?[] content) { }
         public abstract void WriteTo(System.Xml.XmlWriter writer);
         public abstract System.Threading.Tasks.Task WriteToAsync(System.Xml.XmlWriter writer, System.Threading.CancellationToken cancellationToken);
     }
-    public sealed partial class XNodeDocumentOrderComparer : System.Collections.Generic.IComparer<System.Xml.Linq.XNode>, System.Collections.IComparer
+    public sealed partial class XNodeDocumentOrderComparer : System.Collections.Generic.IComparer<System.Xml.Linq.XNode?>, System.Collections.IComparer
     {
         public XNodeDocumentOrderComparer() { }
         public int Compare(System.Xml.Linq.XNode? x, System.Xml.Linq.XNode? y) { throw null; }

Original file line number	Diff line number	Diff line change
`@@ -60,8 +60,6 @@ public override string FormatErrorMessage(string name) =>`
`60`	`60`	`var display = attributes.OfType<DisplayAttribute>().FirstOrDefault();`
`61`	`61`	`if (display != null)`
`62`	`62`	`{`
`63`		`- // TODO-NULLABLE: This will return null if [DisplayName] is specified but no Name has been defined - probably a bug.`
`64`		`- // Should fall back to OtherProperty in this case instead.`
`65`	`63`	`return display.GetName();`
`66`	`64`	`}`
`67`	`65`
Original file line number	Diff line number	Diff line change
`@@ -273,8 +273,6 @@ private void SetResourceAccessorByPropertyLookup()`
`273`	`273`	`_errorMessageResourceType.FullName));`
`274`	`274`	`}`
`275`	`275`
`276`		`-`
`277`		`- // TODO-NULLABLE: If the user-provided resource returns null, an ArgumentNullException is thrown - should probably throw a better exception`
`278`	`276`	`_errorMessageResourceAccessor = () => (string)property.GetValue(null, null)!;`
`279`	`277`	`}`
`280`	`278`
Original file line number	Diff line number	Diff line change
`@@ -137,7 +137,6 @@ public static bool TryValidateObject(object instance, ValidationContext validati`
`137`	`137`	`throw new ArgumentNullException(nameof(instance));`
`138`	`138`	`}`
`139`	`139`
`140`		`- // TODO-NULLABLE: null validationContext isn't supported (GetObjectValidationErrors will throw), remove that check`
`141`	`140`	`if (validationContext != null && instance != validationContext.ObjectInstance)`
`142`	`141`	`{`
`143`	`142`	`throw new ArgumentException(SR.Validator_InstanceMustMatchValidationContextInstance, nameof(instance));`
Original file line number	Diff line number	Diff line change
`@@ -32,7 +32,7 @@ public override string ServerVersion`
`32`	`32`	`{`
`33`	`33`	`get`
`34`	`34`	`{`
`35`		`- // TODO-NULLABLE: This seems like it returns null if the connection is open, whereas the docs say it should throw`
	`35`	`+ // https://github.com/dotnet/runtime/issues/44289: This seems like it returns null if the connection is open, whereas the docs say it should throw`
`36`	`36`	`// InvalidOperationException`
`37`	`37`	`return OuterConnection.Open_GetServerVersion()!;`
`38`	`38`	`}`
Original file line number	Diff line number	Diff line change
`@@ -948,8 +948,7 @@ internal OleDbDataReader Value_HCHAPTER()`
`948`	`948`	`Debug.Assert(NativeDBType.HCHAPTER == DbType, "Value_HCHAPTER");`
`949`	`949`	`Debug.Assert(DBStatus.S_OK == StatusValue(), "Value_HCHAPTER");`
`950`	`950`
`951`		`- // TODO-NULLABLE: This shouldn't return null`
`952`		`- return DataReader().ResetChapter(IndexForAccessor, IndexWithinAccessor, RowBinding, ValueOffset)!;`
	`951`	`+ return DataReader().ResetChapter(IndexForAccessor, IndexWithinAccessor, RowBinding, ValueOffset);`
`953`	`952`	`}`
`954`	`953`
`955`	`954`	`private sbyte Value_I1()`
Original file line number	Diff line number	Diff line change
`@@ -818,7 +818,6 @@ private int ExecuteCommandText(out object executeResult)`
`818`	`818`	`RuntimeHelpers.PrepareConstrainedRegions();`
`819`	`819`	`try`
`820`	`820`	`{`
`821`		`- // TODO-NULLABLE: Code below seems to assume that bindings will always be non-null`
`822`	`821`	`if (null != bindings)`
`823`	`822`	`{ // parameters may be suppressed`
`824`	`823`	`rowbinding = bindings.RowBinding();`
Original file line number	Diff line number	Diff line change
`@@ -33,8 +33,7 @@ public override DbProviderFactory ProviderFactory`
`33`	`33`
`34`	`34`	`protected override DbConnectionInternal CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, object poolGroupProviderInfo, DbConnectionPool? pool, DbConnection? owningObject)`
`35`	`35`	`{`
`36`		`- // TODO-NULLABLE: owningObject may actually be null (see DbConnectionPool.CreateObject), in which case this will throw...`
`37`		`- DbConnectionInternal result = new OleDbConnectionInternal((OleDbConnectionString)options, (OleDbConnection)owningObject!);`
	`36`	`+ DbConnectionInternal result = new OleDbConnectionInternal((OleDbConnectionString)options, (OleDbConnection?)owningObject);`
`38`	`37`	`return result;`
`39`	`38`	`}`
`40`	`39`
Original file line number	Diff line number	Diff line change
`@@ -385,7 +385,7 @@ internal void EnlistTransactionInternal(SysTx.Transaction? transaction)`
`385`	`385`	`using (IDBInfoWrapper wrapper = IDBInfo())`
`386`	`386`	`{`
`387`	`387`	`UnsafeNativeMethods.IDBInfo dbInfo = wrapper.Value;`
`388`		`- // TODO-NULLABLE: check may not be necessary (and thus method may return non-nullable)`
	`388`	`+ // https://github.com/dotnet/runtime/issues/44288: check may not be necessary (and thus method may return non-nullable)`
`389`	`389`	`if (null == dbInfo)`
`390`	`390`	`{`
`391`	`391`	`return null;`
Original file line number	Diff line number	Diff line change
`@@ -951,22 +951,23 @@ protected override DbDataReader GetDbDataReader(int ordinal)`
`951`	`951`	`return GetData(ordinal);`
`952`	`952`	`}`
`953`	`953`
`954`		`- internal OleDbDataReader? ResetChapter(int bindingIndex, int index, RowBinding rowbinding, int valueOffset)`
	`954`	`+ internal OleDbDataReader ResetChapter(int bindingIndex, int index, RowBinding rowbinding, int valueOffset)`
`955`	`955`	`{`
`956`	`956`	`return GetDataForReader(_metadata![bindingIndex + index].ordinal, rowbinding, valueOffset);`
`957`	`957`	`}`
`958`	`958`
`959`		`- private OleDbDataReader? GetDataForReader(IntPtr ordinal, RowBinding rowbinding, int valueOffset)`
	`959`	`+ private OleDbDataReader GetDataForReader(IntPtr ordinal, RowBinding rowbinding, int valueOffset)`
`960`	`960`	`{`
`961`	`961`	`UnsafeNativeMethods.IRowsetInfo rowsetInfo = IRowsetInfo();`
`962`	`962`	`UnsafeNativeMethods.IRowset? result;`
`963`	`963`	`OleDbHResult hr;`
`964`	`964`	`hr = rowsetInfo.GetReferencedRowset((IntPtr)ordinal, ref ODB.IID_IRowset, out result);`
`965`	`965`
`966`	`966`	`ProcessResults(hr);`
	`967`	`+ // Per docs result can be null only when hr is DB_E_NOTAREFERENCECOLUMN which in most of the cases will cause the exception in ProcessResult`
`967`	`968`
`968`	`969`	`OleDbDataReader? reader = null;`
`969`		`- // TODO: Not sure if GetReferenceRowset above actually returns null, calling code seems to assume it doesn't`
	`970`	`+`
`970`	`971`	`if (null != result)`
`971`	`972`	`{`
`972`	`973`	`// only when the first datareader is closed will the connection close`
`@@ -983,6 +984,7 @@ protected override DbDataReader GetDbDataReader(int ordinal)`
`983`	`984`	`_connection.AddWeakReference(reader, OleDbReferenceCollection.DataReaderTag);`
`984`	`985`	`}`
`985`	`986`	`}`
	`987`	`+`
`986`	`988`	`return reader;`
`987`	`989`	`}`
`988`	`990`
`@@ -1022,8 +1024,9 @@ public override Type GetFieldType(int index)`
`1022`	`1024`	`{`
`1023`	`1025`	`if (null != _metadata)`
`1024`	`1026`	`{`
`1025`		`- // TODO-NULLABLE: Should throw if null (empty), though it probably doesn't happen`
`1026`		`- return _metadata[index].type.dataType!;`
	`1027`	`+ Type? fieldType = _metadata[index].type.dataType;`
	`1028`	`+ Debug.Assert(fieldType != null);`
	`1029`	`+ return fieldType;`
`1027`	`1030`	`}`
`1028`	`1031`	`throw ADP.DataReaderNoData();`
`1029`	`1032`	`}`
`@@ -2273,7 +2276,6 @@ internal void DumpToSchemaTable(UnsafeNativeMethods.IRowset? rowset)`
`2273`	`2276`	`using (OleDbDataReader dataReader = new OleDbDataReader(_connection, _command, int.MinValue, 0))`
`2274`	`2277`	`{`
`2275`	`2278`	`dataReader.InitializeIRowset(rowset, ChapterHandle.DB_NULL_HCHAPTER, IntPtr.Zero);`
`2276`		`- // TODO-NULLABLE: BuildSchemaTableInfo asserts that rowset isn't null, but doesn't do anything with it`
`2277`	`2279`	`dataReader.BuildSchemaTableInfo(rowset!, true, false);`
`2278`	`2280`
`2279`	`2281`	`hiddenColumns = GetPropertyValue(ODB.DBPROP_HIDDENCOLUMNS);`