Allow suppression of OnConfiguring() generation.

src/EFCore.Design/Design/Internal/DatabaseOperations.cs

@@ -76,7 +76,8 @@ public virtual SavedModelFiles ScaffoldContext(
             [CanBeNull] string contextNamespace,
             bool useDataAnnotations,
             bool overwriteFiles,
-            bool useDatabaseNames)
+            bool useDatabaseNames,
+            bool suppressOnConfiguring)
         {
             Check.NotEmpty(provider, nameof(provider));
             Check.NotEmpty(connectionString, nameof(connectionString));
@@ -113,7 +114,8 @@ public virtual SavedModelFiles ScaffoldContext(
                     ContextNamespace = finalContextNamespace,
                     Language = _language,
                     ContextDir = MakeDirRelative(outputDir, outputContextDir),
-                    ContextName = dbContextClassName
+                    ContextName = dbContextClassName,
+                    SuppressOnConfiguring = suppressOnConfiguring
                 });
 
             return scaffolder.Save(

src/EFCore.Design/Design/OperationExecutor.cs

@@ -471,12 +471,13 @@ public ScaffoldContext(
                 var useDataAnnotations = (bool)args["useDataAnnotations"];
                 var overwriteFiles = (bool)args["overwriteFiles"];
                 var useDatabaseNames = (bool)args["useDatabaseNames"];
+                var suppressOnConfiguring = (bool)(args["suppressOnConfiguring"] ?? false);
 
                 Execute(
                     () => executor.ScaffoldContextImpl(
                         provider, connectionString, outputDir, outputDbContextDir, dbContextClassName,
                         schemaFilters, tableFilters, modelNamespace, contextNamespace, useDataAnnotations,
-                        overwriteFiles, useDatabaseNames));
+                        overwriteFiles, useDatabaseNames, suppressOnConfiguring));
             }
         }
 
@@ -492,7 +493,8 @@ private IDictionary ScaffoldContextImpl(
             [CanBeNull] string contextNamespace,
             bool useDataAnnotations,
             bool overwriteFiles,
-            bool useDatabaseNames)
+            bool useDatabaseNames,
+            bool suppressOnConfiguring)
         {
             Check.NotNull(provider, nameof(provider));
             Check.NotNull(connectionString, nameof(connectionString));
@@ -502,7 +504,7 @@ private IDictionary ScaffoldContextImpl(
             var files = DatabaseOperations.ScaffoldContext(
                 provider, connectionString, outputDir, outputDbContextDir, dbContextClassName,
                 schemaFilters, tableFilters, modelNamespace, contextNamespace, useDataAnnotations,
-                overwriteFiles, useDatabaseNames);
+                overwriteFiles, useDatabaseNames, suppressOnConfiguring);
 
             return new Hashtable { ["ContextFile"] = files.ContextFile, ["EntityTypeFiles"] = files.AdditionalFiles.ToArray() };
         }

src/EFCore.Design/Properties/DesignStrings.resx

@@ -231,7 +231,7 @@ Change your migrations assembly by using DbContextOptionsBuilder. E.g. options.U
 Change your target project to the migrations project by using the Package Manager Console's Default project drop-down list, or by executing "dotnet ef" from the directory containing the migrations project.</value>
   </data>
   <data name="SensitiveInformationWarning" xml:space="preserve">
-    <value>To protect potentially sensitive information in your connection string, you should move it out of source code. See http://go.microsoft.com/fwlink/?LinkId=723263 for guidance on storing connection strings.</value>
+    <value>To protect potentially sensitive information in your connection string, you should move it out of source code. You can avoid scaffolding the connection string by using the Name= syntax to read it from configuration - see https://go.microsoft.com/fwlink/?linkid=2131148. For more guidance on storing connection strings, see http://go.microsoft.com/fwlink/?LinkId=723263.</value>
     <comment>Localize the URL if we have localized docs.</comment>
   </data>
   <data name="ForceRemoveMigration" xml:space="preserve">

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

@@ -68,7 +68,8 @@ public virtual string WriteCode(
             string? contextNamespace,
             string modelNamespace,
             bool useDataAnnotations,
-            bool suppressConnectionStringWarning)
+            bool suppressConnectionStringWarning,
+            bool suppressOnConfiguring)
         {
             Check.NotNull(model, nameof(model));
 
@@ -97,7 +98,8 @@ public virtual string WriteCode(
                     contextName,
                     connectionString,
                     useDataAnnotations,
-                    suppressConnectionStringWarning);
+                    suppressConnectionStringWarning,
+                    suppressOnConfiguring);
             }
 
             _sb.AppendLine("}");
@@ -116,7 +118,8 @@ protected virtual void GenerateClass(
             [NotNull] string contextName,
             [NotNull] string connectionString,
             bool useDataAnnotations,
-            bool suppressConnectionStringWarning)
+            bool suppressConnectionStringWarning,
+            bool suppressOnConfiguring)
         {
             Check.NotNull(model, nameof(model));
             Check.NotNull(contextName, nameof(contextName));
@@ -130,7 +133,10 @@ protected virtual void GenerateClass(
                 GenerateConstructors(contextName);
                 GenerateDbSets(model);
                 GenerateEntityTypeErrors(model);
-                GenerateOnConfiguring(connectionString, suppressConnectionStringWarning);
+                if (!suppressOnConfiguring)
+                {
+                    GenerateOnConfiguring(connectionString, suppressConnectionStringWarning);
+                }
                 GenerateOnModelCreating(model, useDataAnnotations);
             }
 

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

@@ -100,7 +100,8 @@ public override ScaffoldedModel GenerateModel(
                 options.ContextNamespace,
                 options.ModelNamespace,
                 options.UseDataAnnotations,
-                options.SuppressConnectionStringWarning);
+                options.SuppressConnectionStringWarning,
+                options.SuppressOnConfiguring);
 
             // output DbContext .cs file
             var dbContextFileName = options.ContextName + FileExtension;

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

@@ -29,6 +29,7 @@ string WriteCode(
             [CanBeNull] string? contextNamespace,
             [NotNull] string modelNamespace,
             bool useDataAnnotations,
-            bool suppressConnectionStringWarning);
+            bool suppressConnectionStringWarning,
+            bool suppressOnConfiguring);
     }
 }

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

@@ -9,6 +9,7 @@
 using System.Text;
 using JetBrains.Annotations;
 using Microsoft.EntityFrameworkCore.Design;
+using Microsoft.EntityFrameworkCore.Design.Internal;
 using Microsoft.EntityFrameworkCore.Infrastructure;
 using Microsoft.EntityFrameworkCore.Internal;
 using Microsoft.EntityFrameworkCore.Metadata.Internal;
@@ -32,6 +33,7 @@ public class ReverseEngineerScaffolder : IReverseEngineerScaffolder
         private readonly ICSharpUtilities _cSharpUtilities;
         private readonly ICSharpHelper _code;
         private readonly INamedConnectionStringResolver _connectionStringResolver;
+        private readonly IOperationReporter _reporter;
         private const string DbContextSuffix = "Context";
         private const string DefaultDbContextName = "Model" + DbContextSuffix;
 
@@ -47,21 +49,24 @@ public ReverseEngineerScaffolder(
             [NotNull] IModelCodeGeneratorSelector modelCodeGeneratorSelector,
             [NotNull] ICSharpUtilities cSharpUtilities,
             [NotNull] ICSharpHelper cSharpHelper,
-            [NotNull] INamedConnectionStringResolver connectionStringResolver)
+            [NotNull] INamedConnectionStringResolver connectionStringResolver,
+            [NotNull] IOperationReporter reporter)
         {
             Check.NotNull(databaseModelFactory, nameof(databaseModelFactory));
             Check.NotNull(scaffoldingModelFactory, nameof(scaffoldingModelFactory));
             Check.NotNull(modelCodeGeneratorSelector, nameof(modelCodeGeneratorSelector));
             Check.NotNull(cSharpUtilities, nameof(cSharpUtilities));
             Check.NotNull(cSharpHelper, nameof(cSharpHelper));
             Check.NotNull(connectionStringResolver, nameof(connectionStringResolver));
+            Check.NotNull(reporter, nameof(reporter));
 
             _databaseModelFactory = databaseModelFactory;
             _factory = scaffoldingModelFactory;
             ModelCodeGeneratorSelector = modelCodeGeneratorSelector;
             _cSharpUtilities = cSharpUtilities;
             _code = cSharpHelper;
             _connectionStringResolver = connectionStringResolver;
+            _reporter = reporter;
         }
 
         /// <summary>
@@ -102,6 +107,10 @@ public virtual ScaffoldedModel ScaffoldModel(
             {
                 codeOptions.SuppressConnectionStringWarning = true;
             }
+            else if (!codeOptions.SuppressOnConfiguring)
+            {
+                _reporter.WriteWarning(DesignStrings.SensitiveInformationWarning);
+            }
 
             if (codeOptions.ConnectionString == null)
             {

src/EFCore.Design/Scaffolding/ModelCodeGenerationOptions.cs

@@ -24,6 +24,12 @@ public class ModelCodeGenerationOptions
         /// <value> A value indicating whether to suppress the connection string sensitive information warning. </value>
         public virtual bool SuppressConnectionStringWarning { get; set; }
 
+        /// <summary>
+        ///     Gets or sets a value indicating whether to suppress generation of the OnConfiguring() method.
+        /// </summary>
+        /// <value> A value indicating whether to suppress generation of the OnConfiguring() method. </value>
+        public virtual bool SuppressOnConfiguring { get; set; }
+
         /// <summary>
         ///     Gets or sets the namespace of the project.
         /// </summary>

src/EFCore.Tools/tools/EntityFrameworkCore.PS2.psm1

@@ -175,6 +175,9 @@ function Remove-Migration(
 .PARAMETER Force
     Overwrite existing files.
 
+.PARAMETER NoOnConfiguring
+    Suppress generation of the DbContext.OnConfiguring() method.
+
 .PARAMETER Project
     The project to use.
 
@@ -201,6 +204,7 @@ function Scaffold-DbContext(
     [switch] $DataAnnotations,
     [switch] $UseDatabaseNames,
     [switch] $Force,
+    [switch] $NoOnConfiguring,
     $Project,
     $StartupProject,
     $Namespace,

src/EFCore.Tools/tools/EntityFrameworkCore.psm1

@@ -359,6 +359,9 @@ Register-TabExpansion Scaffold-DbContext @{
 .PARAMETER Force
     Overwrite existing files.
 
+.PARAMETER NoOnConfiguring
+    Suppress generation of the DbContext.OnConfiguring() method.
+
 .PARAMETER Project
     The project to use.
 
@@ -393,6 +396,7 @@ function Scaffold-DbContext
         [switch] $DataAnnotations,
         [switch] $UseDatabaseNames,
         [switch] $Force,
+        [switch] $NoOnConfiguring,
         [string] $Project,
         [string] $StartupProject,
         [string] $Namespace,
@@ -448,6 +452,11 @@ function Scaffold-DbContext
         $params += '--force'
     }
 
+    if ($NoOnConfiguring)
+    {
+        $params += '--no-onconfiguring'
+    }
+
     if ($RemainingArguments -ne $null)
     {
         $params += $RemainingArguments

src/dotnet-ef/Properties/Resources.resx

@@ -330,4 +330,7 @@
   <data name="MigrationsNamespaceDescription" xml:space="preserve">
     <value>Specify to override the namespace for the migration.</value>
   </data>
+  <data name="SuppressOnConfiguringDescription" xml:space="preserve">
+    <value>Suppress generation of the DbContext.OnConfiguring() method.</value>
+  </data>
 </root>

src/ef/Commands/DbContextScaffoldCommand.Configure.cs

@@ -21,6 +21,7 @@ internal partial class DbContextScaffoldCommand : ProjectCommandBase
         private CommandOption _json;
         private CommandOption _namespace;
         private CommandOption _contextNamespace;
+        private CommandOption _suppressOnConfiguring;
 
         public override void Configure(CommandLineApplication command)
         {
@@ -40,6 +41,7 @@ public override void Configure(CommandLineApplication command)
             _json = Json.ConfigureOption(command);
             _namespace = command.Option("-n|--namespace <NAMESPACE>", Resources.NamespaceDescription);
             _contextNamespace = command.Option("--context-namespace <NAMESPACE>", Resources.ContextNamespaceDescription);
+            _suppressOnConfiguring = command.Option("--no-onconfiguring", Resources.SuppressOnConfiguringDescription);
 
             base.Configure(command);
         }

src/ef/Commands/DbContextScaffoldCommand.cs

@@ -39,7 +39,8 @@ protected override int Execute(string[] args)
                 _force.HasValue(),
                 _useDatabaseNames.HasValue(),
                 _namespace.Value(),
-                _contextNamespace.Value());
+                _contextNamespace.Value(),
+                _suppressOnConfiguring.HasValue());
             if (_json.HasValue())
             {
                 ReportJsonResults(result);

src/ef/IOperationExecutor.cs

@@ -29,7 +29,8 @@ IDictionary ScaffoldContext(
             bool overwriteFiles,
             bool useDatabaseNames,
             string entityNamespace,
-            string dbContextNamespace);
+            string dbContextNamespace,
+            bool suppressOnConfiguring);
 
         string ScriptMigration(string fromMigration, string toMigration, bool idempotent, string contextType);
 

src/ef/OperationExecutorBase.cs

@@ -143,7 +143,8 @@ public IDictionary ScaffoldContext(
             bool overwriteFiles,
             bool useDatabaseNames,
             string modelNamespace,
-            string contextNamespace)
+            string contextNamespace,
+            bool suppressOnConfiguring)
             => InvokeOperation<IDictionary>(
                 "ScaffoldContext",
                 new Dictionary<string, object>
@@ -159,7 +160,8 @@ public IDictionary ScaffoldContext(
                     ["overwriteFiles"] = overwriteFiles,
                     ["useDatabaseNames"] = useDatabaseNames,
                     ["modelNamespace"] = modelNamespace,
-                    ["contextNamespace"] = contextNamespace
+                    ["contextNamespace"] = contextNamespace,
+                    ["suppressOnConfiguring"] = suppressOnConfiguring
                 });
 
         public string ScriptMigration(

src/ef/Properties/Resources.resx

@@ -345,4 +345,7 @@
   <data name="RemainingArguments" xml:space="preserve">
     <value>Remaining arguments: '{remainingArguments}'.</value>
   </data>
+  <data name="SuppressOnConfiguringDescription" xml:space="preserve">
+    <value>Suppress generation of the DbContext.OnConfiguring() method.</value>
+  </data>
 </root>

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

@@ -119,6 +119,48 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
                 model => Assert.Empty(model.GetEntityTypes()));
         }
 
+        [ConditionalFact]
+        public void SuppressOnConfiguring_works()
+        {
+            Test(
+                modelBuilder => { },
+                new ModelCodeGenerationOptions { SuppressOnConfiguring = true },
+                code =>
+                {
+                    Assert.Equal(
+                        @"using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Metadata;
+
+namespace TestNamespace
+{
+    public partial class TestDbContext : DbContext
+    {
+        public TestDbContext()
+        {
+        }
+
+        public TestDbContext(DbContextOptions<TestDbContext> options)
+            : base(options)
+        {
+        }
+
+        protected override void OnModelCreating(ModelBuilder modelBuilder)
+        {
+            OnModelCreatingPartial(modelBuilder);
+        }
+
+        partial void OnModelCreatingPartial(ModelBuilder modelBuilder);
+    }
+}
+",
+                        code.ContextFile.Code,
+                        ignoreLineEndingDifferences: true);
+
+                    Assert.Empty(code.AdditionalFiles);
+                });
+        }
+
         [ConditionalFact]
         public void Plugins_work()
         {