Add more specific messages when pending model changes are detected.

Fixes #35133

Author: AndriySvyryd

src/EFCore.Relational/Diagnostics/RelationalEventId.cs

@@ -81,6 +81,7 @@ private enum Id
         NonTransactionalMigrationOperationWarning,
         AcquiringMigrationLock,
         MigrationsUserTransactionWarning,
+        ModelSnapshotNotFound,
 
         // Query events
         QueryClientEvaluationWarning = CoreEventId.RelationalBaseId + 500,
@@ -778,6 +779,19 @@ private static EventId MakeMigrationsId(Id id)
     /// </remarks>
     public static readonly EventId MigrationsUserTransactionWarning = MakeMigrationsId(Id.MigrationsUserTransactionWarning);
 
+    /// <summary>
+    ///     Model snapshot was not found.
+    /// </summary>
+    /// <remarks>
+    ///     <para>
+    ///         This event is in the <see cref="DbLoggerCategory.Migrations" /> category.
+    ///     </para>
+    ///     <para>
+    ///         This event uses the <see cref="MigrationAssemblyEventData" /> payload when used with a <see cref="DiagnosticSource" />.
+    ///     </para>
+    /// </remarks>
+    public static readonly EventId ModelSnapshotNotFound = MakeMigrationsId(Id.ModelSnapshotNotFound);
+
     private static readonly string _queryPrefix = DbLoggerCategory.Query.Name + ".";
 
     private static EventId MakeQueryId(Id id)

src/EFCore.Relational/Diagnostics/RelationalLoggerExtensions.cs

@@ -2343,6 +2343,77 @@ private static string PendingModelChanges(EventDefinitionBase definition, EventD
         return d.GenerateMessage(p.ContextType.ShortDisplayName());
     }
 
+    /// <summary>
+    ///     Logs for the <see cref="RelationalEventId.PendingModelChangesWarning" /> event.
+    /// </summary>
+    /// <param name="diagnostics">The diagnostics logger to use.</param>
+    /// <param name="contextType">The <see cref="DbContext" /> type being used.</param>
+    public static void NonDeterministicModel(
+        this IDiagnosticsLogger<DbLoggerCategory.Migrations> diagnostics,
+        Type contextType)
+    {
+        var definition = RelationalResources.LogNonDeterministicModel(diagnostics);
+
+        if (diagnostics.ShouldLog(definition))
+        {
+            definition.Log(diagnostics, contextType.ShortDisplayName());
+        }
+
+        if (diagnostics.NeedsEventData(definition, out var diagnosticSourceEnabled, out var simpleLogEnabled))
+        {
+            var eventData = new DbContextTypeEventData(
+                definition,
+                NonDeterministicModel,
+                contextType);
+
+            diagnostics.DispatchEventData(definition, eventData, diagnosticSourceEnabled, simpleLogEnabled);
+        }
+    }
+
+    private static string NonDeterministicModel(EventDefinitionBase definition, EventData payload)
+    {
+        var d = (EventDefinition<string>)definition;
+        var p = (DbContextTypeEventData)payload;
+        return d.GenerateMessage(p.ContextType.ShortDisplayName());
+    }
+
+    /// <summary>
+    ///     Logs for the <see cref="RelationalEventId.MigrationsNotFound" /> event.
+    /// </summary>
+    /// <param name="diagnostics">The diagnostics logger to use.</param>
+    /// <param name="migrator">The migrator.</param>
+    /// <param name="migrationsAssembly">The assembly in which migrations are stored.</param>
+    public static void ModelSnapshotNotFound(
+        this IDiagnosticsLogger<DbLoggerCategory.Migrations> diagnostics,
+        IMigrator migrator,
+        IMigrationsAssembly migrationsAssembly)
+    {
+        var definition = RelationalResources.LogNoModelSnapshotFound(diagnostics);
+
+        if (diagnostics.ShouldLog(definition))
+        {
+            definition.Log(diagnostics, migrationsAssembly.Assembly.GetName().Name!);
+        }
+
+        if (diagnostics.NeedsEventData(definition, out var diagnosticSourceEnabled, out var simpleLogEnabled))
+        {
+            var eventData = new MigrationAssemblyEventData(
+                definition,
+                ModelSnapshotNotFound,
+                migrator,
+                migrationsAssembly);
+
+            diagnostics.DispatchEventData(definition, eventData, diagnosticSourceEnabled, simpleLogEnabled);
+        }
+    }
+
+    private static string ModelSnapshotNotFound(EventDefinitionBase definition, EventData payload)
+    {
+        var d = (EventDefinition<string>)definition;
+        var p = (MigrationAssemblyEventData)payload;
+        return d.GenerateMessage(p.MigrationsAssembly.Assembly.GetName().Name!);
+    }
+
     /// <summary>
     ///     Logs for the <see cref="RelationalEventId.NonTransactionalMigrationOperationWarning" /> event.
     /// </summary>

src/EFCore.Relational/Diagnostics/RelationalLoggingDefinitions.cs

@@ -374,7 +374,7 @@ public abstract class RelationalLoggingDefinitions : LoggingDefinitions
     ///     doing so can result in application failures when updating to a new Entity Framework Core release.
     /// </summary>
     [EntityFrameworkInternal]
-    public EventDefinitionBase? LogMigrationsUserTransactionWarning;
+    public EventDefinitionBase? LogMigrationsUserTransaction;
 
     /// <summary>
     ///     This is an internal API that supports the Entity Framework Core infrastructure and not subject to
@@ -673,6 +673,24 @@ public abstract class RelationalLoggingDefinitions : LoggingDefinitions
     [EntityFrameworkInternal]
     public EventDefinitionBase? LogPendingModelChanges;
 
+    /// <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? LogNonDeterministicModel;
+
+    /// <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? LogNoModelSnapshotFound;
+
     /// <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.Relational/Migrations/Internal/Migrator.cs

@@ -3,6 +3,7 @@
 
 using System.Transactions;
 using Microsoft.EntityFrameworkCore.Diagnostics.Internal;
+using Microsoft.EntityFrameworkCore.Metadata.Internal;
 
 namespace Microsoft.EntityFrameworkCore.Migrations.Internal;
 
@@ -93,24 +94,7 @@ public Migrator(
     public virtual void Migrate(string? targetMigration)
     {
         var useTransaction = _connection.CurrentTransaction is null;
-        if (!useTransaction
-            && _executionStrategy.RetriesOnFailure)
-        {
-            throw new NotSupportedException(RelationalStrings.TransactionSuppressedMigrationInUserTransaction);
-        }
-
-        if (RelationalResources.LogPendingModelChanges(_logger).WarningBehavior != WarningBehavior.Ignore
-            && HasPendingModelChanges())
-        {
-            _logger.PendingModelChangesWarning(_currentContext.Context.GetType());
-        }
-
-        if (!useTransaction)
-        {
-            _logger.MigrationsUserTransactionWarning();
-        }
-
-        _logger.MigrateUsingConnection(this, _connection);
+        ValidateMigrations(useTransaction);
 
         using var transactionScope = new TransactionScope(TransactionScopeOption.Suppress, TransactionScopeAsyncFlowOption.Enabled);
 
@@ -235,24 +219,7 @@ public virtual async Task MigrateAsync(
         CancellationToken cancellationToken = default)
     {
         var useTransaction = _connection.CurrentTransaction is null;
-        if (!useTransaction
-            && _executionStrategy.RetriesOnFailure)
-        {
-            throw new NotSupportedException(RelationalStrings.TransactionSuppressedMigrationInUserTransaction);
-        }
-
-        if (RelationalResources.LogPendingModelChanges(_logger).WarningBehavior != WarningBehavior.Ignore
-            && HasPendingModelChanges())
-        {
-            _logger.PendingModelChangesWarning(_currentContext.Context.GetType());
-        }
-
-        if (!useTransaction)
-        {
-            _logger.MigrationsUserTransactionWarning();
-        }
-
-        _logger.MigrateUsingConnection(this, _connection);
+        ValidateMigrations(useTransaction);
 
         using var transactionScope = new TransactionScope(TransactionScopeOption.Suppress, TransactionScopeAsyncFlowOption.Enabled);
 
@@ -382,6 +349,48 @@ await _migrationCommandExecutor.ExecuteNonQueryAsync(
         }
     }
 
+    private void ValidateMigrations(bool useTransaction)
+    {
+        if (!useTransaction
+            && _executionStrategy.RetriesOnFailure)
+        {
+            throw new NotSupportedException(RelationalStrings.TransactionSuppressedMigrationInUserTransaction);
+        }
+
+        if (_migrationsAssembly.Migrations.Count == 0)
+        {
+            _logger.MigrationsNotFound(this, _migrationsAssembly);
+        }
+        else if (_migrationsAssembly.ModelSnapshot == null)
+        {
+            _logger.ModelSnapshotNotFound(this, _migrationsAssembly);
+        }
+        else if (RelationalResources.LogPendingModelChanges(_logger).WarningBehavior != WarningBehavior.Ignore
+            && HasPendingModelChanges())
+        {
+            var modelSource = (ModelSource)_currentContext.Context.GetService<IModelSource>();
+#pragma warning disable EF1001 // Internal EF Core API usage.
+            var newDesignTimeModel = modelSource.CreateModel(
+                _currentContext.Context, _currentContext.Context.GetService<ModelCreationDependencies>(), designTime: true);
+#pragma warning restore EF1001 // Internal EF Core API usage.
+            if (_migrationsModelDiffer.HasDifferences(newDesignTimeModel.GetRelationalModel(), _designTimeModel.Model.GetRelationalModel()))
+            {
+                _logger.NonDeterministicModel(_currentContext.Context.GetType());
+            }
+            else
+            {
+                _logger.PendingModelChangesWarning(_currentContext.Context.GetType());
+            }
+        }
+
+        if (!useTransaction)
+        {
+            _logger.MigrationsUserTransactionWarning();
+        }
+
+        _logger.MigrateUsingConnection(this, _connection);
+    }
+
     private IEnumerable<(string, Func<IReadOnlyList<MigrationCommand>>)> GetMigrationCommandLists(MigratorData parameters)
     {
         var migrationsToApply = parameters.AppliedMigrations;
@@ -449,10 +458,6 @@ protected virtual void PopulateMigrations(
         var appliedMigrations = new Dictionary<string, TypeInfo>();
         var unappliedMigrations = new Dictionary<string, TypeInfo>();
         var appliedMigrationEntrySet = new HashSet<string>(appliedMigrationEntries, StringComparer.OrdinalIgnoreCase);
-        if (_migrationsAssembly.Migrations.Count == 0)
-        {
-            _logger.MigrationsNotFound(this, _migrationsAssembly);
-        }
 
         foreach (var (key, typeInfo) in _migrationsAssembly.Migrations)
         {