Avoid performing empty updates

Fixes #4814
dotnet · Mar 29, 2016 · 705b3fa · 705b3fa
1 parent 645e9a7
commit 705b3fa
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Showing 5 changed files with 39 additions and 3 deletions.
diff --git a/src/Microsoft.EntityFrameworkCore.Relational/Update/Internal/CommandBatchPreparer.cs b/src/Microsoft.EntityFrameworkCore.Relational/Update/Internal/CommandBatchPreparer.cs
@@ -76,7 +76,7 @@ protected virtual IEnumerable<ModificationCommand> CreateModificationCommands(
 
                         command.AddEntry(e);
                         return command;
-                    });
+                    }).Where(c => c.EntityState != EntityState.Modified || c.ColumnModifications.Any(m => m.IsWrite));
         }
 
         // To avoid violating store constraints the modification commands must be sorted

diff --git a/src/Microsoft.EntityFrameworkCore.Relational/Update/UpdateSqlGenerator.cs b/src/Microsoft.EntityFrameworkCore.Relational/Update/UpdateSqlGenerator.cs
@@ -108,7 +108,7 @@ protected virtual void AppendUpdateCommand(
         {
             Check.NotNull(commandStringBuilder, nameof(commandStringBuilder));
             Check.NotEmpty(name, nameof(name));
-            Check.NotNull(writeOperations, nameof(writeOperations));
+            Check.NotEmpty(writeOperations, nameof(writeOperations));
             Check.NotNull(conditionOperations, nameof(conditionOperations));
 
             AppendUpdateCommandHeader(commandStringBuilder, name, schema, writeOperations);

diff --git a/test/Microsoft.EntityFrameworkCore.FunctionalTests/OptimisticConcurrencyTestBase.cs b/test/Microsoft.EntityFrameworkCore.FunctionalTests/OptimisticConcurrencyTestBase.cs
@@ -10,7 +10,6 @@
 using Microsoft.EntityFrameworkCore.FunctionalTests.TestModels.ConcurrencyModel;
 using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Metadata;
-using Microsoft.EntityFrameworkCore.Update;
 using Xunit;
 
 namespace Microsoft.EntityFrameworkCore.FunctionalTests
@@ -125,6 +124,39 @@ public abstract class OptimisticConcurrencyTestBase<TTestStore, TFixture> : ICla
         where TTestStore : TestStore
         where TFixture : F1FixtureBase<TTestStore>, new()
     {
+        [Fact]
+        public virtual async Task Modifying_concurrency_token_only_is_noop()
+        {
+            byte[] firstVersion;
+            using (var context = CreateF1Context())
+            {
+                var driver = context.Drivers.Single(d => d.CarNumber == 1);
+                Assert.NotEqual(1, driver.Version[0]);
+                driver.Podiums = StorePodiums;
+                firstVersion = driver.Version;
+                await context.SaveChangesAsync();
+            }
+
+            byte[] secondVersion;
+            using (var context = CreateF1Context())
+            {
+                var driver = context.Drivers.Single(d => d.CarNumber == 1);
+                Assert.NotEqual(firstVersion, driver.Version);
+                Assert.Equal(StorePodiums, driver.Podiums);
+
+                secondVersion = driver.Version;
+                driver.Version = firstVersion;
+                await context.SaveChangesAsync();
+            }
+
+            using (var validationContext = CreateF1Context())
+            {
+                var driver = validationContext.Drivers.Single(d => d.CarNumber == 1);
+                Assert.Equal(secondVersion, driver.Version);
+                Assert.Equal(StorePodiums, driver.Podiums);
+            }
+        }
+
         #region Concurrency resolution with FK associations
 
         [Fact]

diff --git a/test/Microsoft.EntityFrameworkCore.Relational.Tests/Update/CommandBatchPreparerTest.cs b/test/Microsoft.EntityFrameworkCore.Relational.Tests/Update/CommandBatchPreparerTest.cs
@@ -148,12 +148,14 @@ public void BatchCommands_sorts_added_and_related_modified_entities()
         {
             var configuration = CreateContextServices(CreateSimpleFKModel());
             var stateManager = configuration.GetRequiredService<IStateManager>();
+            var model = configuration.GetRequiredService<IModel>();
 
             var entry = stateManager.GetOrCreateEntry(new FakeEntity { Id = 42, Value = "Test" });
             entry.SetEntityState(EntityState.Added);
 
             var relatedentry = stateManager.GetOrCreateEntry(new RelatedFakeEntity { Id = 42 });
             relatedentry.SetEntityState(EntityState.Modified);
+            relatedentry.SetPropertyModified(relatedentry.EntityType.FindProperty(nameof(RelatedFakeEntity.RelatedId)));
 
             var commandBatches = CreateCommandBatchPreparer().BatchCommands(new[] { relatedentry, entry }).ToArray();
 
@@ -381,6 +383,7 @@ private static IModel CreateSimpleFKModel()
                     b.HasOne<FakeEntity>()
                         .WithOne()
                         .HasForeignKey<RelatedFakeEntity>(c => c.Id);
+                    b.Property(c => c.RelatedId);
                 });
 
             return modelBuilder.Model;

diff --git a/test/Microsoft.EntityFrameworkCore.Sqlite.FunctionalTests/OptimisticConcurrencySqliteTest.cs b/test/Microsoft.EntityFrameworkCore.Sqlite.FunctionalTests/OptimisticConcurrencySqliteTest.cs
@@ -16,6 +16,7 @@ public OptimisticConcurrencySqliteTest(F1SqliteFixture fixture)
         // Override failing tests because SQLite does not allow store-generated row versions.
         // Row version behavior could be imitated on SQLite. See Issue #2195
         // TODO move these tests into the testing just for SqlServer since they don't apply to SQLite
+        public override Task Modifying_concurrency_token_only_is_noop() => Task.FromResult(true);
         public override Task Simple_concurrency_exception_can_be_resolved_with_store_values() => Task.FromResult(true);
         public override Task Simple_concurrency_exception_can_be_resolved_with_client_values() => Task.FromResult(true);
         public override Task Simple_concurrency_exception_can_be_resolved_with_new_values() => Task.FromResult(true);