Support Unicode Attribute

Add Unicode annotation and the capability of generating UnicodeAttribute when scaffolding.

src/EFCore.Abstractions/UnicodeAttribute.cs

@@ -0,0 +1,28 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.EntityFrameworkCore
+{
+    /// <summary>
+    ///     Configures the property as capable of persisting unicode characters. Can only be set on System.String properties.
+    /// </summary>
+    [AttributeUsage(AttributeTargets.Property | AttributeTargets.Field | AttributeTargets.Parameter, AllowMultiple = false)]
+    public sealed class UnicodeAttribute : Attribute
+    {
+        /// <summary>
+        ///     A value indicating whether the property can contain unicode characters or not.
+        /// </summary>
+        public bool IsUnicode { get; }
+
+        /// <summary>
+        ///     Initializes a new instance of the <see cref="UnicodeAttribute" /> class.
+        /// </summary>
+        /// <param name="isUnicode">A value indicating whether the property can contain unicode characters or not.</param>
+        public UnicodeAttribute(bool isUnicode = true)
+        {
+            IsUnicode = isUnicode;
+        }
+    }
+}

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

@@ -287,6 +287,7 @@ protected virtual void GeneratePropertyDataAnnotations([NotNull] IProperty prope
             GenerateRequiredAttribute(property);
             GenerateColumnAttribute(property);
             GenerateMaxLengthAttribute(property);
+            GenerateUnicodeAttribute(property);
 
             var annotations = _annotationCodeGenerator
                 .FilterIgnoredAnnotations(property.GetAnnotations())
@@ -365,6 +366,29 @@ private void GenerateMaxLengthAttribute(IProperty property)
             }
         }
 
+        private void GenerateUnicodeAttribute(IProperty property)
+        {
+            if (property.ClrType != typeof(string))
+            {
+                return;
+            }
+
+            var isUnicode = property.IsUnicode();
+
+            if (isUnicode.HasValue)
+            {
+                if (!isUnicode.Value)
+                {
+                    var unicodeAttribute = new AttributeWriter(nameof(UnicodeAttribute));
+
+                    unicodeAttribute.AddParameter(_code.Literal(false));
+
+                    _sb.AppendLine(unicodeAttribute.ToString());
+                }
+                else _sb.AppendLine(new AttributeWriter(nameof(UnicodeAttribute)).ToString());
+            }
+        }
+
         /// <summary>
         ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
         ///     the same compatibility standards as public APIs. It may be changed or removed without notice in

src/EFCore/Metadata/Conventions/Infrastructure/ProviderConventionSetBuilder.cs

@@ -113,6 +113,7 @@ public virtual ConventionSet CreateConventionSet()
             var stringLengthAttributeConvention = new StringLengthAttributeConvention(Dependencies);
             var timestampAttributeConvention = new TimestampAttributeConvention(Dependencies);
             var backingFieldAttributeConvention = new BackingFieldAttributeConvention(Dependencies);
+            var unicodeAttributeConvention = new UnicodeAttributeConvention(Dependencies);
 
             conventionSet.PropertyAddedConventions.Add(backingFieldAttributeConvention);
             conventionSet.PropertyAddedConventions.Add(backingFieldConvention);
@@ -126,6 +127,7 @@ public virtual ConventionSet CreateConventionSet()
             conventionSet.PropertyAddedConventions.Add(keyAttributeConvention);
             conventionSet.PropertyAddedConventions.Add(keyDiscoveryConvention);
             conventionSet.PropertyAddedConventions.Add(foreignKeyPropertyDiscoveryConvention);
+            conventionSet.PropertyAddedConventions.Add(unicodeAttributeConvention);
 
             conventionSet.EntityTypePrimaryKeyChangedConventions.Add(foreignKeyPropertyDiscoveryConvention);
             conventionSet.EntityTypePrimaryKeyChangedConventions.Add(valueGeneratorConvention);

src/EFCore/Metadata/Conventions/UnicodeAttributeConvention.cs

@@ -0,0 +1,41 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System.Reflection;
+using JetBrains.Annotations;
+using Microsoft.EntityFrameworkCore.Metadata.Builders;
+using Microsoft.EntityFrameworkCore.Metadata.Conventions.Infrastructure;
+
+namespace Microsoft.EntityFrameworkCore.Metadata.Conventions
+{
+    /// <summary>
+    ///     A convention that configures the Unicode based on the <see cref="UnicodeAttribute" /> applied on the property.
+    /// </summary>
+    public class UnicodeAttributeConvention : PropertyAttributeConventionBase<UnicodeAttribute>
+    {
+        /// <summary>
+        ///     Creates a new instance of <see cref="UnicodeAttributeConvention" />.
+        /// </summary>
+        /// <param name="dependencies"> Parameter object containing dependencies for this convention. </param>
+        public UnicodeAttributeConvention([NotNull] ProviderConventionSetBuilderDependencies dependencies)
+            : base(dependencies)
+        {
+        }
+
+        /// <summary>
+        ///     Called after a property is added to the entity type with an attribute on the associated CLR property or field.
+        /// </summary>
+        /// <param name="propertyBuilder"> The builder for the property. </param>
+        /// <param name="attribute"> The attribute. </param>
+        /// <param name="clrMember"> The member that has the attribute. </param>
+        /// <param name="context"> Additional information associated with convention execution. </param>
+        protected override void ProcessPropertyAdded(
+            IConventionPropertyBuilder propertyBuilder,
+            UnicodeAttribute attribute,
+            MemberInfo clrMember,
+            IConventionContext context)
+        {
+            propertyBuilder.IsUnicode(unicode: attribute.IsUnicode, fromDataAnnotation: true);
+        }
+    }
+}

test/EFCore.Design.Tests/Scaffolding/Internal/CSharpEntityTypeGeneratorTest.cs

@@ -846,6 +846,56 @@ public partial class Entity
                 });
         }
 
+        [ConditionalFact]
+        public void UnicodeAttribute_is_generated_for_property()
+        {
+            Test(
+                modelBuilder => modelBuilder
+                    .Entity(
+                        "Entity",
+                        x =>
+                        {
+                            x.Property<int>("Id");
+                            x.Property<string>("A").HasMaxLength(34).IsUnicode();
+                            x.Property<string>("B").HasMaxLength(34).IsUnicode(false);
+                        }),
+                new ModelCodeGenerationOptions { UseDataAnnotations = true },
+                code =>
+                {
+                    AssertFileContents(
+                        @"using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+using Microsoft.EntityFrameworkCore;
+
+#nullable disable
+
+namespace TestNamespace
+{
+    public partial class Entity
+    {
+        [Key]
+        public int Id { get; set; }
+        [StringLength(34)]
+        [Unicode]
+        public string A { get; set; }
+        [StringLength(34)]
+        [Unicode(false)]
+        public string B { get; set; }
+    }
+}
+",
+                        code.AdditionalFiles.Single(f => f.Path == "Entity.cs"));
+                },
+                model =>
+                {
+                    var entitType = model.FindEntityType("TestNamespace.Entity");
+                    Assert.True(entitType.GetProperty("A").IsUnicode());
+                    Assert.False(entitType.GetProperty("B").IsUnicode());
+                });
+        }
+
         [ConditionalFact]
         public void Properties_are_sorted_in_order_of_definition_in_table()
         {

test/EFCore.Specification.Tests/DataAnnotationTestBase.cs

@@ -2375,6 +2375,30 @@ public virtual void TimestampAttribute_throws_if_value_in_database_changed()
                 });
         }
 
+        [ConditionalFact]
+        public virtual void Unicode_annotation_is_enabled()
+        {
+            var modelBuilder = CreateModelBuilder();
+
+            modelBuilder.Entity<UnicodeAnnotationClass>();
+
+            Validate(modelBuilder);
+
+            Assert.True(GetProperty<UnicodeAnnotationClass>(modelBuilder, "PersonFirstName").IsUnicode());
+            Assert.False(GetProperty<UnicodeAnnotationClass>(modelBuilder, "PersonLastName").IsUnicode());
+        }
+
+        protected class UnicodeAnnotationClass
+        {
+            public int Id { get; set; }
+
+            [Unicode]
+            public string PersonFirstName { get; set; }
+
+            [Unicode(false)]
+            public string PersonLastName { get; set; }
+        }
+
         [ConditionalFact]
         public virtual void OwnedEntityTypeAttribute_configures_one_reference_as_owned()
         {

test/EFCore.Tests/Metadata/Conventions/PropertyAttributeConventionTest.cs

@@ -543,6 +543,56 @@ public void BackingFieldAttribute_does_not_override_configuration_from_explicit_
 
         #endregion
 
+        #region UnicodeAttribute
+        [ConditionalFact]
+        public void UnicodeAttribute_overrides_configuration_from_convention_source()
+        {
+            var entityTypeBuilder = CreateInternalEntityTypeBuilder<A>();
+
+            var propertyBuilder = entityTypeBuilder.Property(typeof(string), "UnicodeProperty", ConfigurationSource.Explicit);
+
+            propertyBuilder.IsUnicode(false, ConfigurationSource.Convention);
+
+            RunConvention(propertyBuilder);
+
+            Assert.True(propertyBuilder.Metadata.IsUnicode());
+        }
+
+        [ConditionalFact]
+        public void UnicodeAttribute_does_not_override_configuration_from_explicit_source()
+        {
+            var entityTypeBuilder = CreateInternalEntityTypeBuilder<A>();
+
+            var propertyBuilder = entityTypeBuilder.Property(typeof(string), "UnicodeProperty", ConfigurationSource.Explicit);
+
+            propertyBuilder.IsUnicode(false, ConfigurationSource.Explicit);
+
+            RunConvention(propertyBuilder);
+
+            Assert.False(propertyBuilder.Metadata.IsUnicode());
+        }
+
+        [ConditionalFact]
+        public void UnicodeAttribute_sets_unicode_with_conventional_builder()
+        {
+            var modelBuilder = CreateModelBuilder();
+            var entityTypeBuilder = modelBuilder.Entity<A>();
+
+            Assert.True(entityTypeBuilder.Property(e => e.UnicodeProperty).Metadata.IsUnicode());
+            Assert.False(entityTypeBuilder.Property(e => e.NonUnicodeProperty).Metadata.IsUnicode());
+        }
+
+        [ConditionalFact]
+        public void UnicodeAttribute_on_field_sets_unicode_with_conventional_builder()
+        {
+            var modelBuilder = CreateModelBuilder();
+            var entityTypeBuilder = modelBuilder.Entity<F>();
+
+            Assert.True(entityTypeBuilder.Property<string>(nameof(F.UnicodeProperty)).Metadata.IsUnicode());
+            Assert.False(entityTypeBuilder.Property<string>(nameof(F.NonUnicodeProperty)).Metadata.IsUnicode());
+        }
+        #endregion
+
         [ConditionalFact]
         public void Property_attribute_convention_runs_for_private_property()
         {
@@ -595,6 +645,9 @@ private static void RunConvention(InternalPropertyBuilder propertyBuilder)
 
             new KeyAttributeConvention(dependencies)
                 .ProcessPropertyAdded(propertyBuilder, context);
+
+            new UnicodeAttributeConvention(dependencies)
+                .ProcessPropertyAdded(propertyBuilder, context);
         }
 
         private void RunConvention(InternalEntityTypeBuilder entityTypeBuilder)
@@ -628,6 +681,12 @@ private class A
             [Required]
             public string Name { get; set; }
 
+            [Unicode]
+            public string UnicodeProperty { get; set; }
+
+            [Unicode(false)]
+            public string NonUnicodeProperty { get; set; }
+
             [Key]
             public int MyPrimaryKey { get; set; }
 
@@ -683,6 +742,12 @@ public class F
             [Required]
             public string Name;
 
+            [Unicode]
+            public string UnicodeProperty { get; set; }
+
+            [Unicode(false)]
+            public string NonUnicodeProperty { get; set; }
+
             [Key]
             public int MyPrimaryKey;