Allow value converters to convert nulls (#24687)

Fixes #13850

src/EFCore.Cosmos/Query/Internal/CosmosShapedQueryCompilingExpressionVisitor.CosmosProjectionBindingRemovingExpressionVisitorBase.cs

@@ -712,13 +712,31 @@ var body
  body = Expression.Convert(body, type);
  }
 
+ Expression replaceExpression;
+ if (converter?.ConvertsNulls == true)
+ {
+ replaceExpression = ReplacingExpressionVisitor.Replace(
+ converter.ConvertFromProviderExpression.Parameters.Single(),
+ Expression.Default(converter.ProviderClrType),
+ converter.ConvertFromProviderExpression.Body);
+
+ if (replaceExpression.Type != type)
+ {
+ replaceExpression = Expression.Convert(replaceExpression, type);
+ }
+ }
+ else
+ {
+ replaceExpression = Expression.Default(type);
+ }
+
  body = Expression.Condition(
  Expression.OrElse(
  Expression.Equal(jTokenParameter, Expression.Default(typeof(JToken))),
  Expression.Equal(
  Expression.MakeMemberAccess(jTokenParameter, _jTokenTypePropertyInfo),
  Expression.Constant(JTokenType.Null))),
- Expression.Default(type),
+ replaceExpression,
  body);
 
  valueExpression = Expression.Invoke(Expression.Lambda(body, jTokenParameter), jTokenExpression);

src/EFCore.Design/Migrations/Design/CSharpSnapshotGenerator.cs

@@ -1570,8 +1570,7 @@ private void GenerateFluentApiForDefaultValue(
  IProperty property,
  IndentedStringBuilder stringBuilder)
  {
- var defaultValue = property.GetDefaultValue();
- if (defaultValue == null)
+ if (!property.TryGetDefaultValue(out var defaultValue))
  {
  return;
  }

src/EFCore.Design/Scaffolding/Internal/CSharpDbContextGenerator.cs

@@ -621,17 +621,19 @@ private void GenerateProperty(IProperty property, bool useDataAnnotations)
  }
  }
 
- var defaultValue = property.GetDefaultValue();
- if (defaultValue == DBNull.Value)
+ if (property.TryGetDefaultValue(out var defaultValue))
  {
- lines.Add($".{nameof(RelationalPropertyBuilderExtensions.HasDefaultValue)}()");
- annotations.Remove(RelationalAnnotationNames.DefaultValue);
- }
- else if (defaultValue != null)
- {
- lines.Add(
- $".{nameof(RelationalPropertyBuilderExtensions.HasDefaultValue)}({_code.UnknownLiteral(defaultValue)})");
- annotations.Remove(RelationalAnnotationNames.DefaultValue);
+ if (defaultValue == DBNull.Value)
+ {
+ lines.Add($".{nameof(RelationalPropertyBuilderExtensions.HasDefaultValue)}()");
+ annotations.Remove(RelationalAnnotationNames.DefaultValue);
+ }
+ else if (defaultValue != null)
+ {
+ lines.Add(
+ $".{nameof(RelationalPropertyBuilderExtensions.HasDefaultValue)}({_code.UnknownLiteral(defaultValue)})");
+ annotations.Remove(RelationalAnnotationNames.DefaultValue);
+ }
  }
 
  var valueGenerated = property.ValueGenerated;

src/EFCore.Relational/Extensions/RelationalPropertyExtensions.cs

@@ -385,7 +385,7 @@ public static void SetColumnType(this IMutableProperty property, string? value)
  /// <returns> The default columns to which the property would be mapped. </returns>
  public static IEnumerable<IColumnMappingBase> GetDefaultColumnMappings(this IProperty property)
  => (IEnumerable<IColumnMappingBase>?)property.FindRuntimeAnnotationValue(
- RelationalAnnotationNames.DefaultColumnMappings)
+  RelationalAnnotationNames.DefaultColumnMappings)
  ?? Enumerable.Empty<IColumnMappingBase>();
 
  /// <summary>
@@ -395,7 +395,7 @@ public static IEnumerable<IColumnMappingBase> GetDefaultColumnMappings(this IPro
  /// <returns> The table columns to which the property is mapped. </returns>
  public static IEnumerable<IColumnMapping> GetTableColumnMappings(this IProperty property)
  => (IEnumerable<IColumnMapping>?)property.FindRuntimeAnnotationValue(
- RelationalAnnotationNames.TableColumnMappings)
+  RelationalAnnotationNames.TableColumnMappings)
  ?? Enumerable.Empty<IColumnMapping>();
 
  /// <summary>
@@ -405,7 +405,7 @@ public static IEnumerable<IColumnMapping> GetTableColumnMappings(this IProperty
  /// <returns> The view columns to which the property is mapped. </returns>
  public static IEnumerable<IViewColumnMapping> GetViewColumnMappings(this IProperty property)
  => (IEnumerable<IViewColumnMapping>?)property.FindRuntimeAnnotationValue(
- RelationalAnnotationNames.ViewColumnMappings)
+  RelationalAnnotationNames.ViewColumnMappings)
  ?? Enumerable.Empty<IViewColumnMapping>();
 
  /// <summary>
@@ -415,7 +415,7 @@ public static IEnumerable<IViewColumnMapping> GetViewColumnMappings(this IProper
  /// <returns> The SQL query columns to which the property is mapped. </returns>
  public static IEnumerable<ISqlQueryColumnMapping> GetSqlQueryColumnMappings(this IProperty property)
  => (IEnumerable<ISqlQueryColumnMapping>?)property.FindRuntimeAnnotationValue(
- RelationalAnnotationNames.SqlQueryColumnMappings)
+  RelationalAnnotationNames.SqlQueryColumnMappings)
  ?? Enumerable.Empty<ISqlQueryColumnMapping>();
 
  /// <summary>
@@ -425,7 +425,7 @@ public static IEnumerable<ISqlQueryColumnMapping> GetSqlQueryColumnMappings(this
  /// <returns> The function columns to which the property is mapped. </returns>
  public static IEnumerable<IFunctionColumnMapping> GetFunctionColumnMappings(this IProperty property)
  => (IEnumerable<IFunctionColumnMapping>?)property.FindRuntimeAnnotationValue(
- RelationalAnnotationNames.FunctionColumnMappings)
+  RelationalAnnotationNames.FunctionColumnMappings)
  ?? Enumerable.Empty<IFunctionColumnMapping>();
 
  /// <summary>
@@ -701,7 +701,30 @@ public static void SetIsStored(this IMutableProperty property, bool? value)
  /// <param name="property"> The property. </param>
  /// <returns> The object that is used as the default value for the column this property is mapped to. </returns>
  public static object? GetDefaultValue(this IReadOnlyProperty property)
- => property.FindAnnotation(RelationalAnnotationNames.DefaultValue)?.Value;
+ {
+ property.TryGetDefaultValue(out var defaultValue);
+ return defaultValue;
+ }
+
+ /// <summary>
+ /// Returns the object that is used as the default value for the column this property is mapped to.
+ /// </summary>
+ /// <param name="property"> The property. </param>
+ /// <param name="defaultValue"> The default value, or the CLR default if no explicit default has been set. </param>
+ /// <returns> <see langword="true" /> if a default value has been explicitly set; <see langword="false" /> otherwise. </returns>
+ public static bool TryGetDefaultValue(this IReadOnlyProperty property, out object? defaultValue)
+ {
+ var annotation = property.FindAnnotation(RelationalAnnotationNames.DefaultValue);
+
+ if (annotation != null)
+ {
+ defaultValue = annotation.Value;
+ return defaultValue != null;
+ }
+
+ defaultValue = property.ClrType.GetDefaultValue();
+ return false;
+ }
 
  /// <summary>
  /// Returns the object that is used as the default value for the column this property is mapped to.
@@ -710,20 +733,38 @@ public static void SetIsStored(this IMutableProperty property, bool? value)
  /// <param name="storeObject"> The identifier of the table-like store object containing the column. </param>
  /// <returns> The object that is used as the default value for the column this property is mapped to. </returns>
  public static object? GetDefaultValue(this IReadOnlyProperty property, in StoreObjectIdentifier storeObject)
+ {
+ property.TryGetDefaultValue(storeObject, out var defaultValue);
+ return defaultValue;
+ }
+
+ /// <summary>
+ /// Returns the object that is used as the default value for the column this property is mapped to.
+ /// </summary>
+ /// <param name="property"> The property. </param>
+ /// <param name="storeObject"> The identifier of the table-like store object containing the column. </param>
+ /// <param name="defaultValue"> The default value, or the CLR default if no explicit default has been set. </param>
+ /// <returns> <see langword="true" /> if a default value has been explicitly set; <see langword="false" /> otherwise. </returns>
+ public static bool TryGetDefaultValue(
+ this IReadOnlyProperty property,
+ in StoreObjectIdentifier storeObject,
+ out object? defaultValue)
  {
  var annotation = property.FindAnnotation(RelationalAnnotationNames.DefaultValue);
  if (annotation != null)
  {
- return annotation.Value;
+ defaultValue = annotation.Value;
+ return defaultValue != null;
  }
 
  var sharedTableRootProperty = property.FindSharedStoreObjectRootProperty(storeObject);
  if (sharedTableRootProperty != null)
  {
- return GetDefaultValue(sharedTableRootProperty, storeObject);
+ return TryGetDefaultValue(sharedTableRootProperty, storeObject, out defaultValue);
  }
 
- return null;
+ defaultValue = property.ClrType.GetDefaultValue();
+ return false;
  }
 
  /// <summary>
@@ -982,7 +1023,10 @@ public static bool IsColumnNullable(this IReadOnlyProperty property, in StoreObj
  || IsOptionalSharingDependent(property.DeclaringEntityType, storeObject, 0);
  }
 
- private static bool IsOptionalSharingDependent(IReadOnlyEntityType entityType, in StoreObjectIdentifier storeObject, int recursionDepth)
+ private static bool IsOptionalSharingDependent(
+ IReadOnlyEntityType entityType,
+ in StoreObjectIdentifier storeObject,
+ int recursionDepth)
  {
  if (recursionDepth++ == Metadata.Internal.RelationalEntityTypeExtensions.MaxEntityTypesSharingTable)
  {
@@ -1277,7 +1321,8 @@ public static RelationalTypeMapping GetRelationalTypeMapping(this IReadOnlyPrope
  }
 
  private static IReadOnlyProperty? FindSharedObjectRootPrimaryKeyProperty(
- IReadOnlyProperty property, in StoreObjectIdentifier storeObject)
+ IReadOnlyProperty property,
+ in StoreObjectIdentifier storeObject)
  {
  if (!property.IsPrimaryKey())
  {
@@ -1393,7 +1438,7 @@ public static RelationalTypeMapping GetRelationalTypeMapping(this IReadOnlyPrope
  /// <param name="storeObject"> The identifier of the table-like store object containing the column. </param>
  /// <returns> An object that stores property facet overrides. </returns>
  public static IAnnotatable? FindOverrides(this IProperty property, in StoreObjectIdentifier storeObject)
- => (IAnnotatable?)RelationalPropertyOverrides.Find(property, storeObject);
+ => RelationalPropertyOverrides.Find(property, storeObject);
 
  /// <summary>
  /// <para>
@@ -1410,7 +1455,7 @@ public static RelationalTypeMapping GetRelationalTypeMapping(this IReadOnlyPrope
  public static IMutableAnnotatable GetOrCreateOverrides(
  this IMutableProperty property,
  in StoreObjectIdentifier storeObject)
- => (IMutableAnnotatable)RelationalPropertyOverrides.GetOrCreate(property, storeObject);
+ => RelationalPropertyOverrides.GetOrCreate(property, storeObject);
 
  /// <summary>
  /// <para>
@@ -1427,6 +1472,6 @@ public static IMutableAnnotatable GetOrCreateOverrides(
  public static IConventionAnnotatable GetOrCreateOverrides(
  this IConventionProperty property,
  in StoreObjectIdentifier storeObject)
- => (IConventionAnnotatable)RelationalPropertyOverrides.GetOrCreate(property, storeObject);
+ => RelationalPropertyOverrides.GetOrCreate(property, storeObject);
  }
 }

src/EFCore.Relational/Metadata/Conventions/RelationalValueGenerationConvention.cs

@@ -153,9 +153,9 @@ private void ProcessTableChanged(
  return valueGenerated
  ?? (property.GetComputedColumnSql(storeObject) != null
  ? ValueGenerated.OnAddOrUpdate
- : property.GetDefaultValue(storeObject) != null || property.GetDefaultValueSql(storeObject) != null
+ : property.TryGetDefaultValue(storeObject, out _) || property.GetDefaultValueSql(storeObject) != null
  ? ValueGenerated.OnAdd
- : (ValueGenerated?)null);
+ : null);
  }
  }
 }

src/EFCore.Relational/Metadata/Conventions/StoreGenerationConvention.cs

@@ -115,7 +115,7 @@ protected virtual void Validate(
  IConventionProperty property,
  in StoreObjectIdentifier storeObject)
  {
- if (property.GetDefaultValue(storeObject) != null)
+ if (property.TryGetDefaultValue(storeObject, out _))
  {
  if (property.GetDefaultValueSql(storeObject) != null)
  {

src/EFCore.Relational/Metadata/IColumn.cs

@@ -71,14 +71,33 @@ public virtual object? DefaultValue
  {
  get
  {
- var property = PropertyMappings.First().Property;
- var value = property.GetDefaultValue(StoreObjectIdentifier.Table(Table.Name, Table.Schema));
- var converter = property.GetValueConverter() ?? PropertyMappings.First().TypeMapping?.Converter;
+ TryGetDefaultValue(out var defaultValue);
+ return defaultValue;
+ }
+ }
+
+ /// <summary>
+ /// Gets the object that is used as the default value for this column.
+ /// </summary>
+ /// <param name="defaultValue"> The default value. </param>
+ /// <returns> True if the default value was explicitly set; false otherwise. </returns>
+ public virtual bool TryGetDefaultValue(out object? defaultValue)
+ {
+ var property = PropertyMappings.First().Property;
 
- return converter != null
- ? converter.ConvertToProvider(value)
- : value;
+ if (!property.TryGetDefaultValue(StoreObjectIdentifier.Table(Table.Name, Table.Schema), out defaultValue))
+ {
+ return false;
+ }
+
+ var converter = property.GetValueConverter() ?? PropertyMappings.First().TypeMapping?.Converter;
+
+ if (converter != null)
+ {
+ defaultValue = converter.ConvertToProvider(defaultValue);
  }
+
+ return true;
  }
 
  /// <summary>