RevEng: Consider skip navigation names when generating identifier for…

… members of class

Resolves #26496

We had mechanism to generate unique identifiers to assign to skip navigations but the code to find existing identifiers lacked skip navigations. So skip navigation names were not unique-fied throwing error when trying to add skip navigation with same name

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

@@ -1003,6 +1003,11 @@ protected virtual List<string> ExistingIdentifiers(IReadOnlyEntityType entityTyp
             }
 
             existingIdentifiers.AddRange(entityType.GetNavigations().Select(p => p.Name));
+            if (!(AppContext.TryGetSwitch("Microsoft.EntityFrameworkCore.Issue26496", out var enabled)
+                && enabled))
+            {
+                existingIdentifiers.AddRange(entityType.GetSkipNavigations().Select(p => p.Name));
+            }
             return existingIdentifiers;
         }
 

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

@@ -2256,5 +2256,122 @@ public void Scaffold_skip_navigation_for_many_to_many_join_table_basic()
                 });
 
         }
+
+        [ConditionalFact]
+        public void Scaffold_skip_navigation_for_many_to_many_join_table_self_ref()
+        {
+            var database = new DatabaseModel
+            {
+                Tables =
+                {
+                    new DatabaseTable
+                    {
+                        Name = "Products",
+                        Columns =
+                        {
+                            new DatabaseColumn
+                            {
+                                Name = "Id",
+                                StoreType = "int"
+                            }
+                        },
+                        PrimaryKey = new DatabasePrimaryKey { Columns = { new DatabaseColumnRef("Id") } }
+                    },
+                    new DatabaseTable
+                    {
+                        Name = "RelatedProducts",
+                        Columns =
+                        {
+                            new DatabaseColumn
+                            {
+                                Name = "Id",
+                                StoreType = "int"
+                            },
+                            new DatabaseColumn
+                            {
+                                Name = "ProductId",
+                                StoreType = "int"
+                            }
+                        },
+                        PrimaryKey = new DatabasePrimaryKey {
+                            Columns = { new DatabaseColumnRef("Id"), new DatabaseColumnRef("ProductId") } },
+                        ForeignKeys =
+                        {
+                            new DatabaseForeignKey
+                            {
+                                Columns = { new DatabaseColumnRef("Id") },
+                                PrincipalColumns = { new DatabaseColumnRef("Id") },
+                                PrincipalTable = new DatabaseTableRef("Products"),
+                            },
+                            new DatabaseForeignKey
+                            {
+                                Columns = { new DatabaseColumnRef("ProductId") },
+                                PrincipalColumns = { new DatabaseColumnRef("Id") },
+                                PrincipalTable = new DatabaseTableRef("Products"),
+                            }
+                        }
+                    },
+                    new DatabaseTable
+                    {
+                        Name = "SubProducts",
+                        Columns =
+                        {
+                            new DatabaseColumn
+                            {
+                                Name = "Id",
+                                StoreType = "int"
+                            },
+                            new DatabaseColumn
+                            {
+                                Name = "ProductId",
+                                StoreType = "int"
+                            }
+                        },
+                        PrimaryKey = new DatabasePrimaryKey {
+                            Columns = { new DatabaseColumnRef("Id"), new DatabaseColumnRef("ProductId") } },
+                        ForeignKeys =
+                        {
+                            new DatabaseForeignKey
+                            {
+                                Columns = { new DatabaseColumnRef("Id") },
+                                PrincipalColumns = { new DatabaseColumnRef("Id") },
+                                PrincipalTable = new DatabaseTableRef("Products"),
+                            },
+                            new DatabaseForeignKey
+                            {
+                                Columns = { new DatabaseColumnRef("ProductId") },
+                                PrincipalColumns = { new DatabaseColumnRef("Id") },
+                                PrincipalTable = new DatabaseTableRef("Products"),
+                            }
+                        }
+                    }
+                }
+            };
+
+            var model = _factory.Create(database, new ModelReverseEngineerOptions());
+
+            Assert.Collection(
+                model.GetEntityTypes().OrderBy(e => e.Name),
+                t1 =>
+                {
+                    Assert.Empty(t1.GetNavigations());
+                    Assert.Collection(t1.GetSkipNavigations(),
+                        s => Assert.Equal("Ids", s.Name),
+                        s => Assert.Equal("IdsNavigation", s.Name),
+                        s => Assert.Equal("Products", s.Name),
+                        s => Assert.Equal("ProductsNavigation", s.Name));
+                },
+                t2 =>
+                {
+                    Assert.Empty(t2.GetNavigations());
+                    Assert.Equal(2, t2.GetForeignKeys().Count());
+                },
+                t2 =>
+                {
+                    Assert.Empty(t2.GetNavigations());
+                    Assert.Equal(2, t2.GetForeignKeys().Count());
+                });
+
+        }
     }
 }