From 947fd9d3b0f1016740b1ee74e56ea6ea3da160bb Mon Sep 17 00:00:00 2001
From: lajones <lajones@microsoft.com>
Date: Mon, 30 Mar 2020 17:14:15 -0700
Subject: [PATCH] Fixes 20303. Throw in IsUnique if cannot find appropriate
 NavProp.

---
 .../Internal/InternalForeignKeyBuilder.cs     | 10 ++++
 src/EFCore/Properties/CoreStrings.Designer.cs |  8 +++
 src/EFCore/Properties/CoreStrings.resx        |  3 +
 .../ModelBuilding/OwnedTypesTestBase.cs       | 57 +++++++++++++++----
 4 files changed, 68 insertions(+), 10 deletions(-)

diff --git a/src/EFCore/Metadata/Internal/InternalForeignKeyBuilder.cs b/src/EFCore/Metadata/Internal/InternalForeignKeyBuilder.cs
index 7f8de4886f6..fb2a290b281 100644
--- a/src/EFCore/Metadata/Internal/InternalForeignKeyBuilder.cs
+++ b/src/EFCore/Metadata/Internal/InternalForeignKeyBuilder.cs
@@ -1397,6 +1397,16 @@ public virtual InternalForeignKeyBuilder IsUnique(bool? unique, ConfigurationSou
                 return null;
             }
 
+            if (resetToDependent
+                && Metadata.PrincipalToDependent.GetConfigurationSource() == ConfigurationSource.Explicit)
+            {
+                throw new InvalidOperationException(
+                    CoreStrings.UnableToSetIsUnique(
+                        unique.Value,
+                        Metadata.PrincipalToDependent.PropertyInfo.Name,
+                        Metadata.PrincipalEntityType.DisplayName()));
+            }
+
             using var batch = Metadata.DeclaringEntityType.Model.ConventionDispatcher.DelayConventions();
             var builder = this;
             if (resetToDependent)
diff --git a/src/EFCore/Properties/CoreStrings.Designer.cs b/src/EFCore/Properties/CoreStrings.Designer.cs
index dab2e1a0d33..94b5bfa8628 100644
--- a/src/EFCore/Properties/CoreStrings.Designer.cs
+++ b/src/EFCore/Properties/CoreStrings.Designer.cs
@@ -2596,6 +2596,14 @@ public static string QueryEntityMaterializationConditionWrongShape([CanBeNull] o
                 GetString("QueryEntityMaterializationConditionWrongShape", nameof(entityType)),
                 entityType);
 
+        /// <summary>
+        ///     Unable to set IsUnique to '{isUnique}' on the navigation property '{navigationName}' on the entity type '{entityType}' because the navigation property has the opposite multiplicity.'
+        /// </summary>
+        public static string UnableToSetIsUnique([CanBeNull] object isUnique, [CanBeNull] object navigationName, [CanBeNull] object entityType)
+            => string.Format(
+                GetString("UnableToSetIsUnique", nameof(isUnique), nameof(navigationName), nameof(entityType)),
+                isUnique, navigationName, entityType);
+
         private static string GetString(string name, params string[] formatterNames)
         {
             var value = _resourceManager.GetString(name);
diff --git a/src/EFCore/Properties/CoreStrings.resx b/src/EFCore/Properties/CoreStrings.resx
index a66b5a6e5f4..a2659268d1a 100644
--- a/src/EFCore/Properties/CoreStrings.resx
+++ b/src/EFCore/Properties/CoreStrings.resx
@@ -1369,4 +1369,7 @@
   <data name="QueryEntityMaterializationConditionWrongShape" xml:space="preserve">
     <value>Materialization condition passed for entity shaper of entity type '{entityType}' is not of correct shape. Materialization condition must be LambdaExpression of 'Func&lt;ValueBuffer, IEntityType&gt;'</value>
   </data>
+  <data name="UnableToSetIsUnique" xml:space="preserve">
+    <value>Unable to set IsUnique to '{isUnique}' on the navigation property '{navigationName}' on the entity type '{entityType}' because the navigation property has the opposite multiplicity.'</value>
+  </data>
 </root>
\ No newline at end of file
diff --git a/test/EFCore.Tests/ModelBuilding/OwnedTypesTestBase.cs b/test/EFCore.Tests/ModelBuilding/OwnedTypesTestBase.cs
index 00766257b37..c896262c5de 100644
--- a/test/EFCore.Tests/ModelBuilding/OwnedTypesTestBase.cs
+++ b/test/EFCore.Tests/ModelBuilding/OwnedTypesTestBase.cs
@@ -190,17 +190,21 @@ public virtual void Changing_ownership_uniqueness_throws()
             {
                 var modelBuilder = CreateModelBuilder();
 
-                modelBuilder.Entity<Customer>().OwnsOne(
-                    c => c.Details,
-                    r =>
-                    {
-                        r.HasOne(d => d.Customer)
-                            .WithMany();
-                    });
-
                 Assert.Equal(
-                    CoreStrings.NavigationNotAdded(nameof(Customer), nameof(Customer.Details), nameof(CustomerDetails)),
-                    Assert.Throws<InvalidOperationException>(() => modelBuilder.FinalizeModel()).Message);
+                    CoreStrings.UnableToSetIsUnique(
+                        false,
+                        nameof(Customer.Details),
+                        nameof(Customer)),
+                    Assert.Throws<InvalidOperationException>(
+                        () => modelBuilder
+                                .Entity<Customer>()
+                                .OwnsOne(
+                                    c => c.Details,
+                                    r =>
+                                    {
+                                        r.HasOne(d => d.Customer)
+                                            .WithMany();
+                                    })).Message);
             }
 
             [ConditionalFact]
@@ -1437,6 +1441,39 @@ public virtual void Navigations_on_OwnsMany_Owned_types_can_set_access_mode_usin
                 Assert.Equal(PropertyAccessMode.Field, principal.FindNavigation("OwnedDependents").GetPropertyAccessMode());
                 Assert.Equal(PropertyAccessMode.Property, dependent.FindNavigation("OneToManyOwner").GetPropertyAccessMode());
             }
+
+            [ConditionalFact]
+            public virtual void Attempt_to_create_OwnsMany_on_a_reference_throws()
+            {
+                var modelBuilder = CreateModelBuilder();
+
+                Assert.Equal(
+                    CoreStrings.UnableToSetIsUnique(
+                        false,
+                        "OwnedDependent",
+                        typeof(OneToOneNavPrincipalOwner).Name),
+                    Assert.Throws<InvalidOperationException>(
+                        () => modelBuilder
+                                .Entity<OneToOneNavPrincipalOwner>()
+                                .OwnsMany<OwnedNavDependent>("OwnedDependent")).Message
+                 );
+            }
+
+            [ConditionalFact]
+            public virtual void Attempt_to_create_OwnsOne_on_a_collection_throws()
+            {
+                var modelBuilder = CreateModelBuilder();
+
+                Assert.Equal(
+                    CoreStrings.UnableToSetIsUnique(
+                        true,
+                        "OwnedDependents",
+                        typeof(OneToManyNavPrincipalOwner).Name),
+                    Assert.Throws<InvalidOperationException>(
+                        () => modelBuilder
+                                .Entity<OneToManyNavPrincipalOwner>()
+                                .OwnsOne<OwnedOneToManyNavDependent>("OwnedDependents")).Message);
+            }
         }
     }
 }