Support C# nullable references (#3606)

* feat: support C# nullable references fixes #2690 * Nullable reflection support for .net standard 2.0+ Include source files for targets lower than .net 6.0. * Work with unsupported nullable reflection * Attempt to fix NotImplementedEx. in reflection. Looks like we have our own MemberInfo-derivative. * Add new UseNullableTypesMetadata option * Attempt to ignore warnings from imported c# code. * Nullable Associations Does not apply to collections. * Added tests * Use new ThrowHelper * Maybe fix compilation?? * Fix warning in Release build * Fix runtime targets once more * Upgrade Nullability.Source and fix one build error * Fix lint-errors in CI build * Factor out code dealing with C# NRT * fix merge * Update Source/LinqToDB/Mapping/ColumnDescriptor.cs Co-authored-by: Shane Krueger <shane@acdmail.com> * Update Source/LinqToDB/Mapping/Nullability.cs Co-authored-by: Shane Krueger <shane@acdmail.com> * Update Source/LinqToDB/Mapping/Nullability.cs Co-authored-by: Shane Krueger <shane@acdmail.com> * Update Tests/Linq/Mapping/CanBeNullTests.cs Co-authored-by: Shane Krueger <shane@acdmail.com> * Update Source/LinqToDB/Properties/GlobalSuppressions.cs Co-authored-by: Shane Krueger <shane@acdmail.com> * Update Source/LinqToDB/Mapping/Nullability.cs Co-authored-by: Shane Krueger <shane@acdmail.com> * Update .gitignore Co-authored-by: MaceWindu <MaceWindu@users.noreply.github.com> Co-authored-by: Shane Krueger <shane@acdmail.com>
linq2db · Jan 24, 2023 · 14ee4c8 · 14ee4c8
1 parent 13fbe5f
commit 14ee4c8
Show file tree

Hide file tree

Showing 15 changed files with 379 additions and 53 deletions.
diff --git a/.gitignore b/.gitignore
@@ -24,3 +24,4 @@ linq2db.sln.ide/
 /.temp
 .vs/
 packages/
+.vscode/
diff --git a/Directory.Packages.props b/Directory.Packages.props
@@ -13,6 +13,8 @@
 		<PackageVersion Include="Microsoft.CSharp"                                      Version="4.7.0"         />
 		<PackageVersion Include="Microsoft.Bcl.AsyncInterfaces"                         Version="7.0.0"         />
 		<PackageVersion Include="System.ComponentModel.Annotations"                     Version="5.0.0"         />
+		<!--Source of NullabilityInfoContext for runtimes before .net 6-->
+		<PackageVersion Include="Nullability.Source"                                    Version="2.1.0"         />
 		<!--build support-->
 		<PackageVersion Include="Microsoft.CodeAnalysis.BannedApiAnalyzers"             Version="3.3.4-beta1.22559.1" />
 		<PackageVersion Include="Microsoft.CodeAnalysis.NetAnalyzers"                   Version="7.0.0"         />

diff --git a/Source/LinqToDB/Common/Configuration.cs b/Source/LinqToDB/Common/Configuration.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Data;
 using System.Linq.Expressions;
+using System.Reflection;
 using System.Threading.Tasks;
 
 using JetBrains.Annotations;
@@ -101,6 +102,26 @@ public static class Configuration
 		/// Set to 0 to truncate all string data.
 		/// </remarks>
 		public static int MaxStringParameterLengthLogging { get; set; } = 200;
+
+		private static bool _useNullableTypesMetadata;
+		/// <summary>
+		/// Whether or not Nullable Reference Types annotations from C#
+		/// are read and taken into consideration to determine if a
+		/// column or association can be null.
+		/// Nullable Types can be overriden with explicit CanBeNull
+		/// annotations in [Column], [Association], or [Nullable].
+		/// </summary>
+		/// <remarks>Defaults to false.</remarks>
+		public static bool UseNullableTypesMetadata 
+		{ 
+			get => _useNullableTypesMetadata;
+			set 
+			{
+				// Can't change the default value of "false" on platforms where nullable metadata is unavailable.				
+				if (value) Mapping.Nullability.EnsureSupport();
+				_useNullableTypesMetadata = value;
+			}
+		}	
 
 		public static class Data
 		{

diff --git a/Source/LinqToDB/Linq/Builder/TableBuilder.TableContext.cs b/Source/LinqToDB/Linq/Builder/TableBuilder.TableContext.cs
@@ -1715,7 +1715,7 @@ public ContextInfo(IBuildContext context, ISqlExpression? field, Expression? cur
 							attribute.QueryExpressionMethod,
 							attribute.QueryExpression,
 							attribute.Storage,
-							attribute.CanBeNull,
+							attribute.ConfiguredCanBeNull,
 							attribute.AliasName
 						);
 				}

diff --git a/Source/LinqToDB/LinqToDB.csproj b/Source/LinqToDB/LinqToDB.csproj
@@ -111,6 +111,13 @@
 		<Reference Include="System.ComponentModel.DataAnnotations" />
 	</ItemGroup>
 
+	<ItemGroup>
+		<PackageReference Include="Nullability.Source">
+			<PrivateAssets>all</PrivateAssets>
+			<IncludeAssets>runtime; build; native; contentfiles; analyzers</IncludeAssets>
+		</PackageReference>
+	</ItemGroup>
+
 	<ItemGroup Condition=" '$(TargetFramework)' == 'netstandard2.0' ">
 		<PackageReference Include="System.Data.DataSetExtensions" />
 	</ItemGroup>

diff --git a/Source/LinqToDB/Mapping/AssociationAttribute.cs b/Source/LinqToDB/Mapping/AssociationAttribute.cs
@@ -30,9 +30,7 @@ public class AssociationAttribute : MappingAttribute
 		/// Creates attribute instance.
 		/// </summary>
 		public AssociationAttribute()
-		{
-			CanBeNull = true;
-		}
+		{ }
 
 		/// <summary>
 		/// Gets or sets comma-separated list of association key members on this side of association.
@@ -105,13 +103,20 @@ public AssociationAttribute()
 		/// </summary>
 		public string?      Storage             { get; set; }
 
+		internal bool?      ConfiguredCanBeNull;
 		/// <summary>
 		/// Defines type of join:
 		/// - inner join for <c>CanBeNull = false</c>;
-		/// - left join for <c>CanBeNull = true</c>.
-		/// Default value: <c>true</c>.
+		/// - outer join for <c>CanBeNull = true</c>.
+		/// When using Configuration.UseNullableTypesMetadata, the default value 
+		/// for associations (cardinality 1) is derived from nullability.
+		/// Otherwise the default value is <c>true</c> (for collections and when option is disabled).
 		/// </summary>
-		public bool         CanBeNull           { get; set; }
+		public bool         CanBeNull           
+		{ 
+			get => ConfiguredCanBeNull ?? true; 
+			set => ConfiguredCanBeNull = value;
+		}
 
 		/// <summary>
 		/// Gets or sets alias for association. Used in SQL generation process.

diff --git a/Source/LinqToDB/Mapping/AssociationDescriptor.cs b/Source/LinqToDB/Mapping/AssociationDescriptor.cs
@@ -39,7 +39,7 @@ public class AssociationDescriptor
 			string?     expressionQueryMethod,
 			Expression? expressionQuery,
 			string?     storage,
-			bool        canBeNull,
+			bool?       canBeNull,
 			string?     aliasName)
 		{
 			if (memberInfo == null) throw new ArgumentNullException(nameof(memberInfo));
@@ -63,7 +63,7 @@ public class AssociationDescriptor
 			ExpressionQueryMethod = expressionQueryMethod;
 			ExpressionQuery       = expressionQuery;
 			Storage               = storage;
-			CanBeNull             = canBeNull;
+			CanBeNull             = canBeNull ?? AnalyzeCanBeNull();
 			AliasName             = aliasName;
 		}
 
@@ -107,7 +107,7 @@ public class AssociationDescriptor
 		/// <summary>
 		/// Gets alias for association. Used in SQL generation process.
 		/// </summary>
-		public string? AliasName           { get; }
+		public string?     AliasName           { get; }
 
 		/// <summary>
 		/// Parse comma-separated list of association key column members into string array.
@@ -309,5 +309,16 @@ public bool HasQueryMethod()
 
 			return lambda;
 		}
+
+		private bool AnalyzeCanBeNull()
+		{
+			// Note that nullability of Collections can't be determined from types.
+			// OUTER JOIN are usually materialized in non-nullable, but empty, collections.
+			// For example, `IList<Product> Products` might well require an OUTER JOIN.
+			// Neither `IList<Product>?` nor `IList<Product?>` would be correct.
+			return Configuration.UseNullableTypesMetadata && !IsList && Nullability.TryAnalyzeMember(MemberInfo, out var isNullable)
+				? isNullable
+				: true;
+		}
 	}
 }
diff --git a/Source/LinqToDB/Mapping/ColumnDescriptor.cs b/Source/LinqToDB/Mapping/ColumnDescriptor.cs
@@ -88,25 +88,6 @@ public ColumnDescriptor(MappingSchema mappingSchema, EntityDescriptor entityDesc
 				StorageInfo = expr.Member;
 			}
 
-			var defaultCanBeNull = false;
-
-			if (columnAttribute?.HasCanBeNull() == true)
-				CanBeNull = columnAttribute.CanBeNull;
-			else
-			{
-				var na = mappingSchema.GetAttribute<NullableAttribute>(MemberAccessor.TypeAccessor.Type, MemberInfo);
-
-				if (na != null)
-				{
-					CanBeNull = na.CanBeNull;
-				}
-				else
-				{
-					CanBeNull        = mappingSchema.GetCanBeNull(MemberType);
-					defaultCanBeNull = true;
-				}
-			}
-
 			if (columnAttribute?.HasIsIdentity() == true)
 			{
 				IsIdentity = columnAttribute.IsIdentity;
@@ -125,9 +106,8 @@ public ColumnDescriptor(MappingSchema mappingSchema, EntityDescriptor entityDesc
 
 			SkipOnInsert = columnAttribute?.HasSkipOnInsert() == true ? columnAttribute.SkipOnInsert : IsIdentity;
 			SkipOnUpdate = columnAttribute?.HasSkipOnUpdate() == true ? columnAttribute.SkipOnUpdate : IsIdentity;
-
-			if (defaultCanBeNull && IsIdentity)
-				CanBeNull = false;
+
+			CanBeNull = AnalyzeCanBeNull(columnAttribute);
 
 			if (columnAttribute?.HasIsPrimaryKey() == true)
 				IsPrimaryKey = columnAttribute.IsPrimaryKey;
@@ -169,6 +149,24 @@ public ColumnDescriptor(MappingSchema mappingSchema, EntityDescriptor entityDesc
 			}
 		}
 
+		private bool AnalyzeCanBeNull(ColumnAttribute? columnAttribute)
+		{
+			if (columnAttribute?.HasCanBeNull() == true)
+				return columnAttribute.CanBeNull;
+
+			var na = MappingSchema.GetAttribute<NullableAttribute>(MemberAccessor.TypeAccessor.Type, MemberInfo);
+			if (na != null)
+				return na.CanBeNull;
+
+			if (Configuration.UseNullableTypesMetadata && Nullability.TryAnalyzeMember(MemberInfo, out var isNullable))
+				return isNullable;
+
+			if (IsIdentity) 
+				return false;
+
+			return MappingSchema.GetCanBeNull(MemberType);
+		}
+
 		/// <summary>
 		/// Gets MappingSchema for current ColumnDescriptor.
 		/// </summary>
@@ -401,7 +399,6 @@ public virtual bool ShouldSkip(object obj, EntityDescriptor descriptor, SkipModi
 		/// Gets value converter for specific column.
 		/// </summary>
 		public IValueConverter? ValueConverter  { get; }
-
 		LambdaExpression?    _getOriginalValueLambda;
 
 		LambdaExpression?    _getDbValueLambda;

diff --git a/Source/LinqToDB/Mapping/DynamicColumnInfo.cs b/Source/LinqToDB/Mapping/DynamicColumnInfo.cs
@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Globalization;
 using System.Reflection;
 using LinqToDB.Common;
@@ -112,6 +113,10 @@ public override object[] GetCustomAttributes(Type attributeType, bool inherit)
 #pragma warning restore RS0030 // Do not used banned APIs
 			=> Array<object>.Empty;
 
+		/// <inheritdoc cref="MemberInfo.GetCustomAttributesData()"/>
+		public override IList<CustomAttributeData> GetCustomAttributesData()
+			=> Array<CustomAttributeData>.Empty;
+
 		/// <inheritdoc cref="MemberInfo.IsDefined"/>
 		public override bool IsDefined(Type attributeType, bool inherit)
 			=> false;

diff --git a/Source/LinqToDB/Mapping/EntityDescriptor.cs b/Source/LinqToDB/Mapping/EntityDescriptor.cs
@@ -204,8 +204,16 @@ void Init()
 				if (aa != null)
 				{
 					_associations.Add(new AssociationDescriptor(
-						TypeAccessor.Type, member.MemberInfo, aa.GetThisKeys(), aa.GetOtherKeys(),
-						aa.ExpressionPredicate, aa.Predicate, aa.QueryExpressionMethod, aa.QueryExpression, aa.Storage, aa.CanBeNull,
+						TypeAccessor.Type, 
+						member.MemberInfo, 
+						aa.GetThisKeys(), 
+						aa.GetOtherKeys(),
+						aa.ExpressionPredicate, 
+						aa.Predicate, 
+						aa.QueryExpressionMethod, 
+						aa.QueryExpression,
+						aa.Storage,
+						aa.ConfiguredCanBeNull,
 						aa.AliasName));
 					continue;
 				}

diff --git a/Source/LinqToDB/Mapping/EntityMappingBuilder.cs b/Source/LinqToDB/Mapping/EntityMappingBuilder.cs
@@ -179,7 +179,7 @@ public EntityMappingBuilder<TE> Entity<TE>(string? configuration = null)
 			Expression<Func<TEntity, TProperty>>   prop,
 			Expression<Func<TEntity, TThisKey>>    thisKey,
 			Expression<Func<TProperty, TOtherKey>> otherKey,
-			bool                                   canBeNull = true)
+			bool?                                  canBeNull = null)
 		{
 			if (prop     == null) throw new ArgumentNullException(nameof(prop));
 			if (thisKey  == null) throw new ArgumentNullException(nameof(thisKey));
@@ -188,7 +188,12 @@ public EntityMappingBuilder<TE> Entity<TE>(string? configuration = null)
 			var thisKeyName  = MemberHelper.GetMemberInfo(thisKey).Name;
 			var otherKeyName = MemberHelper.GetMemberInfo(otherKey).Name;
 
-			return Property( prop ).HasAttribute( new AssociationAttribute { ThisKey = thisKeyName, OtherKey = otherKeyName, CanBeNull = canBeNull } );
+			return Property( prop ).HasAttribute(new AssociationAttribute 
+			{ 
+				ThisKey             = thisKeyName, 
+				OtherKey            = otherKeyName, 
+				ConfiguredCanBeNull = canBeNull,
+			});
 		}
 
 		/// <summary>
@@ -206,7 +211,7 @@ public EntityMappingBuilder<TE> Entity<TE>(string? configuration = null)
 			Expression<Func<TEntity, IEnumerable<TPropElement>>> prop,
 			Expression<Func<TEntity, TThisKey>>                  thisKey,
 			Expression<Func<TPropElement, TOtherKey>>            otherKey,
-			bool                                                 canBeNull = true)
+			bool?                                                canBeNull = null)
 		{
 			if (prop     == null) throw new ArgumentNullException(nameof(prop));
 			if (thisKey  == null) throw new ArgumentNullException(nameof(thisKey));
@@ -215,7 +220,12 @@ public EntityMappingBuilder<TE> Entity<TE>(string? configuration = null)
 			var thisKeyName  = MemberHelper.GetMemberInfo(thisKey).Name;
 			var otherKeyName = MemberHelper.GetMemberInfo(otherKey).Name;
 
-			return Property( prop ).HasAttribute( new AssociationAttribute { ThisKey = thisKeyName, OtherKey = otherKeyName, CanBeNull = canBeNull } );
+			return Property( prop ).HasAttribute(new AssociationAttribute 
+			{ 
+				ThisKey             = thisKeyName, 
+				OtherKey            = otherKeyName, 
+				ConfiguredCanBeNull = canBeNull,
+			});
 		}
 
 		/// <summary>
@@ -229,12 +239,16 @@ public EntityMappingBuilder<TE> Entity<TE>(string? configuration = null)
 		public PropertyMappingBuilder<TEntity, IEnumerable<TOther>> Association<TOther>(
 			Expression<Func<TEntity, IEnumerable<TOther>>> prop,
 			Expression<Func<TEntity, TOther, bool>>        predicate,
-			bool                                           canBeNull = true)
+			bool?                                          canBeNull = null)
 		{
 			if (prop      == null) throw new ArgumentNullException(nameof(prop));
 			if (predicate == null) throw new ArgumentNullException(nameof(predicate));
 
-			return Property( prop ).HasAttribute( new AssociationAttribute { Predicate = predicate, CanBeNull = canBeNull } );
+			return Property( prop ).HasAttribute(new AssociationAttribute 
+			{ 
+				Predicate           = predicate, 
+				ConfiguredCanBeNull = canBeNull,
+			});
 		}
 
 		/// <summary>
@@ -248,12 +262,16 @@ public EntityMappingBuilder<TE> Entity<TE>(string? configuration = null)
 		public PropertyMappingBuilder<TEntity, TOther> Association<TOther>(
 			Expression<Func<TEntity, TOther>>       prop,
 			Expression<Func<TEntity, TOther, bool>> predicate,
-			bool                                    canBeNull = true)
+			bool?                                   canBeNull = null)
 		{
 			if (prop      == null) throw new ArgumentNullException(nameof(prop));
 			if (predicate == null) throw new ArgumentNullException(nameof(predicate));
 
-			return Property( prop ).HasAttribute( new AssociationAttribute { Predicate = predicate, CanBeNull = canBeNull } );
+			return Property( prop ).HasAttribute(new AssociationAttribute 
+			{ 
+				Predicate           = predicate, 
+				ConfiguredCanBeNull = canBeNull,
+			});
 		}
 
 		/// <summary>
@@ -267,12 +285,16 @@ public EntityMappingBuilder<TE> Entity<TE>(string? configuration = null)
 		public PropertyMappingBuilder<TEntity, IEnumerable<TOther>> Association<TOther>(
 			Expression<Func<TEntity, IEnumerable<TOther>>>              prop,
 			Expression<Func<TEntity, IDataContext, IQueryable<TOther>>> queryExpression,
-			bool                                                        canBeNull = true)
+			bool?                                                       canBeNull = null)
 		{
 			if (prop            == null) throw new ArgumentNullException(nameof(prop));
 			if (queryExpression == null) throw new ArgumentNullException(nameof(queryExpression));
 
-			return Property( prop ).HasAttribute( new AssociationAttribute { QueryExpression = queryExpression, CanBeNull = canBeNull } );
+			return Property( prop ).HasAttribute(new AssociationAttribute
+			{ 
+				QueryExpression     = queryExpression, 
+				ConfiguredCanBeNull = canBeNull,
+			});
 		}
 
 		/// <summary>
@@ -286,12 +308,16 @@ public EntityMappingBuilder<TE> Entity<TE>(string? configuration = null)
 		public PropertyMappingBuilder<TEntity, TOther> Association<TOther>(
 			Expression<Func<TEntity, TOther>>                           prop,
 			Expression<Func<TEntity, IDataContext, IQueryable<TOther>>> queryExpression,
-			bool                                                        canBeNull = true)
+			bool?                                                       canBeNull = null)
 		{
 			if (prop            == null) throw new ArgumentNullException(nameof(prop));
 			if (queryExpression == null) throw new ArgumentNullException(nameof(queryExpression));
 
-			return Property( prop ).HasAttribute( new AssociationAttribute { QueryExpression = queryExpression, CanBeNull = canBeNull } );
+			return Property( prop ).HasAttribute(new AssociationAttribute 
+			{ 
+				QueryExpression     = queryExpression, 
+				ConfiguredCanBeNull = canBeNull,
+			});
 		}
 
 		/// <summary>