Add metadata for configuring required dependents

Part of #12100

src/EFCore.Relational/Migrations/Internal/MigrationsModelDiffer.cs

@@ -1913,7 +1913,8 @@ protected virtual Dictionary<IEntityType, List<ITable>> DiffData(
 
                         foreach (var targetProperty in entry.EntityType.GetProperties())
                         {
-                            if (!(targetProperty.ValueGenerated == ValueGenerated.Never || targetProperty.ValueGenerated == ValueGenerated.OnAdd))
+                            if (targetProperty.ValueGenerated != ValueGenerated.Never
+                                && targetProperty.ValueGenerated != ValueGenerated.OnAdd)
                             {
                                 continue;
                             }

src/EFCore/Diagnostics/CoreEventId.cs

@@ -86,8 +86,8 @@ private enum Id
             ShadowPropertyCreated = CoreBaseId + 600,
             RedundantIndexRemoved,
             IncompatibleMatchingForeignKeyProperties,
-            RequiredAttributeOnDependent,
-            RequiredAttributeOnBothNavigations,
+            RequiredAttributeOnDependent, // Unused
+            RequiredAttributeOnBothNavigations, // Unused
             ConflictingShadowForeignKeysWarning,
             MultiplePrimaryKeyCandidates,
             MultipleNavigationProperties,
@@ -99,13 +99,14 @@ private enum Id
             ConflictingForeignKeyAttributesOnNavigationAndPropertyWarning,
             RedundantForeignKeyWarning,
             NonNullableInverted, // Unused
-            NonNullableReferenceOnBothNavigations,
-            NonNullableReferenceOnDependent,
+            NonNullableReferenceOnBothNavigations, // Unused
+            NonNullableReferenceOnDependent, // Unused
             RequiredAttributeInverted, // Unused
             RequiredAttributeOnCollection,
             CollectionWithoutComparer,
             ConflictingKeylessAndKeyAttributesWarning,
             PossibleIncorrectRequiredNavigationWithQueryFilterInteractionWarning,
+            RequiredAttributeOnSkipNavigation,
 
             // ChangeTracking events
             DetectChangesStarting = CoreBaseId + 800,
@@ -435,6 +436,7 @@ public static readonly EventId InvalidIncludePathError
         ///         This event uses the <see cref="TwoPropertyBaseCollectionsEventData" /> payload when used with a <see cref="DiagnosticSource" />.
         ///     </para>
         /// </summary>
+        [Obsolete]
         public static readonly EventId RequiredAttributeOnBothNavigations = MakeModelId(Id.RequiredAttributeOnBothNavigations);
 
         /// <summary>
@@ -448,6 +450,7 @@ public static readonly EventId InvalidIncludePathError
         ///         This event uses the <see cref="TwoPropertyBaseCollectionsEventData" /> payload when used with a <see cref="DiagnosticSource" />.
         ///     </para>
         /// </summary>
+        [Obsolete]
         public static readonly EventId NonNullableReferenceOnBothNavigations = MakeModelId(Id.NonNullableReferenceOnBothNavigations);
 
         /// <summary>
@@ -461,6 +464,7 @@ public static readonly EventId InvalidIncludePathError
         ///         This event uses the <see cref="NavigationEventData" /> payload when used with a <see cref="DiagnosticSource" />.
         ///     </para>
         /// </summary>
+        [Obsolete]
         public static readonly EventId RequiredAttributeOnDependent = MakeModelId(Id.RequiredAttributeOnDependent);
 
         /// <summary>
@@ -474,6 +478,7 @@ public static readonly EventId InvalidIncludePathError
         ///         This event uses the <see cref="NavigationEventData" /> payload when used with a <see cref="DiagnosticSource" />.
         ///     </para>
         /// </summary>
+        [Obsolete]
         public static readonly EventId NonNullableReferenceOnDependent = MakeModelId(Id.NonNullableReferenceOnDependent);
 
         /// <summary>
@@ -489,6 +494,19 @@ public static readonly EventId InvalidIncludePathError
         /// </summary>
         public static readonly EventId RequiredAttributeOnCollection = MakeModelId(Id.RequiredAttributeOnCollection);
 
+        /// <summary>
+        ///     <para>
+        ///         The <see cref="RequiredAttribute" /> on the skip navigation property was ignored.
+        ///     </para>
+        ///     <para>
+        ///         This event is in the <see cref="DbLoggerCategory.Model" /> category.
+        ///     </para>
+        ///     <para>
+        ///         This event uses the <see cref="SkipNavigationEventData" /> payload when used with a <see cref="DiagnosticSource" />.
+        ///     </para>
+        /// </summary>
+        public static readonly EventId RequiredAttributeOnSkipNavigation = MakeModelId(Id.RequiredAttributeOnSkipNavigation);
+
         /// <summary>
         ///     <para>
         ///         The properties that best match the foreign key convention are already used by a different foreign key.

src/EFCore/Diagnostics/CoreLoggerExtensions.cs

@@ -1284,6 +1284,7 @@ public static void RequiredAttributeInverted(
             }
         }
 
+        [Obsolete]
         private static string RequiredAttributeInverted(EventDefinitionBase definition, EventData payload)
         {
             var d = (EventDefinition<string, string>)definition;
@@ -1319,6 +1320,7 @@ public static void NonNullableInverted(
             }
         }
 
+        [Obsolete]
         private static string NonNullableInverted(EventDefinitionBase definition, EventData payload)
         {
             var d = (EventDefinition<string, string>)definition;
@@ -1332,6 +1334,7 @@ private static string NonNullableInverted(EventDefinitionBase definition, EventD
         /// <param name="diagnostics"> The diagnostics logger to use. </param>
         /// <param name="firstNavigation"> The first navigation property. </param>
         /// <param name="secondNavigation"> The second navigation property. </param>
+        [Obsolete]
         public static void RequiredAttributeOnBothNavigations(
             [NotNull] this IDiagnosticsLogger<DbLoggerCategory.Model> diagnostics,
             [NotNull] INavigation firstNavigation,
@@ -1361,6 +1364,7 @@ public static void RequiredAttributeOnBothNavigations(
             }
         }
 
+        [Obsolete]
         private static string RequiredAttributeOnBothNavigations(EventDefinitionBase definition, EventData payload)
         {
             var d = (EventDefinition<string, string, string, string>)definition;
@@ -1380,6 +1384,7 @@ private static string RequiredAttributeOnBothNavigations(EventDefinitionBase def
         /// <param name="diagnostics"> The diagnostics logger to use. </param>
         /// <param name="firstNavigation"> The first navigation property. </param>
         /// <param name="secondNavigation"> The second navigation property. </param>
+        [Obsolete]
         public static void NonNullableReferenceOnBothNavigations(
             [NotNull] this IDiagnosticsLogger<DbLoggerCategory.Model> diagnostics,
             [NotNull] INavigation firstNavigation,
@@ -1409,6 +1414,7 @@ public static void NonNullableReferenceOnBothNavigations(
             }
         }
 
+        [Obsolete]
         private static string NonNullableReferenceOnBothNavigations(EventDefinitionBase definition, EventData payload)
         {
             var d = (EventDefinition<string, string, string, string>)definition;
@@ -1427,6 +1433,7 @@ private static string NonNullableReferenceOnBothNavigations(EventDefinitionBase
         /// </summary>
         /// <param name="diagnostics"> The diagnostics logger to use. </param>
         /// <param name="navigation"> The navigation property. </param>
+        [Obsolete]
         public static void RequiredAttributeOnDependent(
             [NotNull] this IDiagnosticsLogger<DbLoggerCategory.Model> diagnostics,
             [NotNull] INavigation navigation)
@@ -1451,6 +1458,7 @@ public static void RequiredAttributeOnDependent(
             }
         }
 
+        [Obsolete]
         private static string RequiredAttributeOnDependent(EventDefinitionBase definition, EventData payload)
         {
             var d = (EventDefinition<string, string>)definition;
@@ -1463,6 +1471,7 @@ private static string RequiredAttributeOnDependent(EventDefinitionBase definitio
         /// </summary>
         /// <param name="diagnostics"> The diagnostics logger to use. </param>
         /// <param name="navigation"> The navigation property. </param>
+        [Obsolete]
         public static void NonNullableReferenceOnDependent(
             [NotNull] this IDiagnosticsLogger<DbLoggerCategory.Model> diagnostics,
             [NotNull] INavigation navigation)
@@ -1488,6 +1497,7 @@ public static void NonNullableReferenceOnDependent(
             }
         }
 
+        [Obsolete]
         private static string NonNullableReferenceOnDependent(EventDefinitionBase definition, EventData payload)
         {
             var d = (EventDefinition<string, string>)definition;
@@ -1529,6 +1539,40 @@ private static string RequiredAttributeOnCollection(EventDefinitionBase definiti
             return d.GenerateMessage(p.Navigation.DeclaringEntityType.DisplayName(), p.Navigation.Name);
         }
 
+        /// <summary>
+        ///     Logs for the <see cref="CoreEventId.RequiredAttributeOnSkipNavigation" /> event.
+        /// </summary>
+        /// <param name="diagnostics"> The diagnostics logger to use. </param>
+        /// <param name="navigation"> The navigation property. </param>
+        public static void RequiredAttributeOnSkipNavigation(
+            [NotNull] this IDiagnosticsLogger<DbLoggerCategory.Model> diagnostics,
+            [NotNull] ISkipNavigation navigation)
+        {
+            var definition = CoreResources.LogRequiredAttributeOnSkipNavigation(diagnostics);
+
+            if (diagnostics.ShouldLog(definition))
+            {
+                definition.Log(diagnostics, navigation.DeclaringEntityType.DisplayName(), navigation.Name);
+            }
+
+            if (diagnostics.NeedsEventData(definition, out var diagnosticSourceEnabled, out var simpleLogEnabled))
+            {
+                var eventData = new SkipNavigationEventData(
+                    definition,
+                    RequiredAttributeOnSkipNavigation,
+                    navigation);
+
+                diagnostics.DispatchEventData(definition, eventData, diagnosticSourceEnabled, simpleLogEnabled);
+            }
+        }
+
+        private static string RequiredAttributeOnSkipNavigation(EventDefinitionBase definition, EventData payload)
+        {
+            var d = (EventDefinition<string, string>)definition;
+            var p = (SkipNavigationEventData)payload;
+            return d.GenerateMessage(p.Navigation.DeclaringEntityType.DisplayName(), p.Navigation.Name);
+        }
+
         /// <summary>
         ///     Logs for the <see cref="CoreEventId.ConflictingShadowForeignKeysWarning" /> event.
         /// </summary>

src/EFCore/Diagnostics/LoggingDefinitions.cs

@@ -521,6 +521,7 @@ public abstract class LoggingDefinitions
         ///     doing so can result in application failures when updating to a new Entity Framework Core release.
         /// </summary>
         [EntityFrameworkInternal]
+        [Obsolete]
         public EventDefinitionBase LogRequiredAttributeOnDependent;
 
         /// <summary>
@@ -530,6 +531,7 @@ public abstract class LoggingDefinitions
         ///     doing so can result in application failures when updating to a new Entity Framework Core release.
         /// </summary>
         [EntityFrameworkInternal]
+        [Obsolete]
         public EventDefinitionBase LogNonNullableReferenceOnDependent;
 
         /// <summary>
@@ -539,6 +541,7 @@ public abstract class LoggingDefinitions
         ///     doing so can result in application failures when updating to a new Entity Framework Core release.
         /// </summary>
         [EntityFrameworkInternal]
+        [Obsolete]
         public EventDefinitionBase LogRequiredAttributeOnBothNavigations;
 
         /// <summary>
@@ -548,6 +551,7 @@ public abstract class LoggingDefinitions
         ///     doing so can result in application failures when updating to a new Entity Framework Core release.
         /// </summary>
         [EntityFrameworkInternal]
+        [Obsolete]
         public EventDefinitionBase LogNonNullableReferenceOnBothNavigations;
 
         /// <summary>
@@ -568,6 +572,15 @@ public abstract class LoggingDefinitions
         [EntityFrameworkInternal]
         public EventDefinitionBase LogRequiredAttributeOnCollection;
 
+        /// <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
+        ///     any release. You should only use it directly in your code with extreme caution and knowing that
+        ///     doing so can result in application failures when updating to a new Entity Framework Core release.
+        /// </summary>
+        [EntityFrameworkInternal]
+        public EventDefinitionBase LogRequiredAttributeOnSkipNavigation;
+
         /// <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/Infrastructure/CoreOptionsExtension.cs

@@ -49,8 +49,7 @@ private WarningsConfiguration _warningsConfiguration
                 .TryWithExplicit(CoreEventId.ManyServiceProvidersCreatedWarning, WarningBehavior.Throw)
                 .TryWithExplicit(CoreEventId.LazyLoadOnDisposedContextWarning, WarningBehavior.Throw)
                 .TryWithExplicit(CoreEventId.DetachedLazyLoadingWarning, WarningBehavior.Throw)
-                .TryWithExplicit(CoreEventId.InvalidIncludePathError, WarningBehavior.Throw)
-                .TryWithExplicit(CoreEventId.RequiredAttributeOnDependent, WarningBehavior.Throw);
+                .TryWithExplicit(CoreEventId.InvalidIncludePathError, WarningBehavior.Throw);
 
         /// <summary>
         ///     Creates a new set of options with everything set to default values.

src/EFCore/Metadata/Builders/IConventionForeignKeyBuilder.cs

@@ -298,7 +298,7 @@ bool CanSetNavigations(
             bool fromDataAnnotation = false);
 
         /// <summary>
-        ///     Configures whether this is a required relationship (i.e. whether none the foreign key properties can
+        ///     Configures whether this is a required relationship (i.e. whether none of the foreign key properties can
         ///     be assigned <see langword="null" />).
         /// </summary>
         /// <param name="required">
@@ -313,7 +313,7 @@ bool CanSetNavigations(
         IConventionForeignKeyBuilder IsRequired(bool? required, bool fromDataAnnotation = false);
 
         /// <summary>
-        ///     Returns a value indicating whether this relationship requiredness can be configured
+        ///     Returns a value indicating whether the relationship requiredness can be configured
         ///     from the current configuration source.
         /// </summary>
         /// <param name="required">
@@ -324,6 +324,33 @@ bool CanSetNavigations(
         /// <returns> <see langword="true" /> if the relationship requiredness can be configured. </returns>
         bool CanSetIsRequired(bool? required, bool fromDataAnnotation = false);
 
+        /// <summary>
+        ///     Configures whether the dependent end is required (i.e. whether the principal to dependent navigation can
+        ///     be assigned <see langword="null" />).
+        /// </summary>
+        /// <param name="required">
+        ///     A value indicating whether the dependent end is required.
+        ///     <see langword="null" /> to reset to default.
+        /// </param>
+        /// <param name="fromDataAnnotation"> Indicates whether the configuration was specified using a data annotation. </param>
+        /// <returns>
+        ///     The same builder instance if the dependent end requiredness was configured,
+        ///     <see langword="null" /> otherwise.
+        /// </returns>
+        IConventionForeignKeyBuilder IsRequiredDependent(bool? required, bool fromDataAnnotation = false);
+
+        /// <summary>
+        ///     Returns a value indicating whether the dependent end requiredness can be configured
+        ///     from the current configuration source.
+        /// </summary>
+        /// <param name="required">
+        ///     A value indicating whether this is a required relationship.
+        ///     <see langword="null" /> to reset to default.
+        /// </param>
+        /// <param name="fromDataAnnotation"> Indicates whether the configuration was specified using a data annotation. </param>
+        /// <returns> <see langword="true" /> if the relationship requiredness can be configured. </returns>
+        bool CanSetIsRequiredDependent(bool? required, bool fromDataAnnotation = false);
+
         /// <summary>
         ///     Configures whether this relationship defines an ownership
         ///     (i.e. whether the dependent entity must always be accessed via the navigation from the principal entity).

src/EFCore/Metadata/Builders/IConventionNavigationBuilder.cs

@@ -74,5 +74,27 @@ public interface IConventionNavigationBuilder : IConventionPropertyBaseBuilder
         ///     <see langword="null" /> otherwise.
         /// </returns>
         IConventionNavigationBuilder AutoInclude(bool? autoInclude, bool fromDataAnnotation = false);
+
+        /// <summary>
+        ///     Returns a value indicating whether this navigation requiredness can be configured
+        ///     from the current configuration source.
+        /// </summary>
+        /// <param name="required"> A value indicating whether the navigation should be required. </param>
+        /// <param name="fromDataAnnotation"> Indicates whether the configuration was specified using a data annotation. </param>
+        /// <returns> <see langword="true" /> if requiredness can be set for this navigation. </returns>
+        bool CanSetIsRequired(bool? required, bool fromDataAnnotation = false);
+
+        /// <summary>
+        ///     Configures whether this navigation is required.
+        /// </summary>
+        /// <param name="required">
+        ///     A value indicating whether this is a required navigation.
+        ///     <see langword="null" /> to reset to default.
+        /// </param>
+        /// <param name="fromDataAnnotation"> Indicates whether the configuration was specified using a data annotation. </param>
+        /// <returns>
+        ///     The same builder instance if the requiredness was configured, <see langword="null" /> otherwise.
+        /// </returns>
+        IConventionNavigationBuilder IsRequired(bool? required, bool fromDataAnnotation = false);
     }
 }