EF Core 7 Reverse Engineer Error

[aespitia]

Error when reverse engineering a model from an existing DB:

Microsoft SQL Server 2014 12.0.6439.10 (X64)

using EFCore 7 RC1

System.InvalidOperationException: Reverse engineer error:
System.NullReferenceException: Object reference not set to an instance of an object.
at string Microsoft.EntityFrameworkCore.Scaffolding.Internal.CSharpDbContextGenerator.TransformText()
at string Microsoft.EntityFrameworkCore.Scaffolding.Internal.CSharpModelGenerator.ProcessTemplate(ITextTransformation transformation)
at ScaffoldedModel Microsoft.EntityFrameworkCore.Scaffolding.Internal.CSharpModelGenerator.GenerateModel(IModel model, ModelCodeGenerationOptions options)
at ScaffoldedModel RevEng.Core.ReverseEngineerScaffolder.ScaffoldModel(string connectionString, DatabaseModelFactoryOptions databaseOptions, ModelReverseEngineerOptions modelOptions, ModelCodeGenerationOptions codeOptions, bool removeNullableBoolDefaults, bool excludeNavigations, bool dbContextOnly, bool entitiesOnly, bool useSchemaFolders) in C:/Code/Github/EFCorePowerTools/src/GUI/RevEng.Core/ReverseEngineerScaffolder.cs:line 374
at SavedModelFiles RevEng.Core.ReverseEngineerScaffolder.GenerateDbContext(ReverseEngineerCommandOptions options, List schemas, string outputContextDir, string modelNamespace, string contextNamespace) in C:/Code/Github/EFCorePowerTools/src/GUI/RevEng.Core/ReverseEngineerScaffolder.cs:line 99
at ReverseEngineerResult RevEng.Core.ReverseEngineerRunner.GenerateFiles(ReverseEngineerCommandOptions options) in C:/Code/Github/EFCorePowerTools/src/GUI/RevEng.Core/ReverseEngineerRunner.cs:line 93
at int EfReveng.Program.Main(string[] args) in C:/Code/Github/EFCorePowerTools/src/GUI/efreveng/Program.cs:line 68

at ReverseEngineerResult EFCorePowerTools.Handlers.ReverseEngineer.ResultDeserializer.BuildResult(string output)
at async Task EFCorePowerTools.Handlers.ReverseEngineer.EfRevEngLauncher.GetOutputAsync()
at async Task EFCorePowerTools.Handlers.ReverseEngineer.EfRevEngLauncher.LaunchExternalRunnerAsync(ReverseEngineerOptions options, CodeGenerationMode codeGenerationMode, Project project)
at async Task EFCorePowerTools.Handlers.ReverseEngineer.ReverseEngineerHandler.GenerateFilesAsync(Project project, ReverseEngineerOptions options, Tuple<bool, string> containsEfCoreReference)
at async Task EFCorePowerTools.Handlers.ReverseEngineer.ReverseEngineerHandler.ReverseEngineerCodeFirstAsync(Project project, string optionsPath, bool onlyGenerate, bool fromSqlProj)

[ErikEJ]

Are you using the T4 templates. Try to rename / delete the CodeTemplates folder.

[ErikEJ]

Ping?

[aespitia]

Are you using the T4 templates. Try to rename / delete the CodeTemplates folder.

from what i can tell, i am not using T4 templates. i have a working model if generated using the EF6 option, this error comes from the EF7 preview option when reverse engineering.

i don't see a codeTemplates folder to remove.

I'm using EF Core Power Tools 2.5.1142.0 on VS 2022

[ErikEJ]

I am unable to repro locally, can you share the database schema, for example via a .dacpac and your efpt.config.json file?

[aespitia]

I've removed the tables, but there are tables in 3 different schemas, as well as views, functions, and stored procs. object types 0, 1, 2, and 3.

{
"CodeGenerationMode": 3,
"ContextClassName": "Context",
"ContextNamespace": "",
"DefaultDacpacSchema": null,
"FilterSchemas": false,
"IncludeConnectionString": false,
"ModelNamespace": null,
"OutputContextPath": "",
"OutputPath": "Generated",
"PreserveCasingWithRegex": true,
"ProjectRootNamespace": "Project.Domain",
"Schemas": null,
"SelectedHandlebarsLanguage": 0,
"SelectedToBeGenerated": 0,
"UiHint": "SERVER.DBNAME",
"UseBoolPropertiesWithoutDefaultSql": true,
"UseDatabaseNames": false,
"UseDbContextSplitting": true,
"UseFluentApiOnly": false,
"UseHandleBars": false,
"UseHierarchyId": false,
"UseInflector": true,
"UseLegacyPluralizer": true,
"UseManyToManyEntity": false,
"UseNoConstructor": false,
"UseNoDefaultConstructor": false,
"UseNoNavigations": false,
"UseNoObjectFilter": false,
"UseNodaTime": false,
"UseNullableReferences": true,
"UseSchemaFolders": false,
"UseSpatial": false,
"UseT4": false
}

[ErikEJ]

I need the database schema (either .sql script or bacpac file)

[aespitia]

I can't send the schema, but i'll see if I can recreate it in a dummy schema in a new project

[aespitia]

dbproject.zip

this project seems to throw the error for me if i try pointing to the dacpac

[ErikEJ]

With the same error? I am not able to repro that (.dacpac functionality is currently borken with EF Core 7)

[ErikEJ]

Alos not able to repro if I publish the database project

[aespitia]

OK, yes, I got a different error from the dacpac, not the same as the original. will tweak the sample project some more to see if I can narrow down the cause.

[ErikEJ]

Yeah, sorry, but .dacpac support for EF Core 7 is currently pending

[aespitia]

Is there any log or output you can turn on to see what the progress was to see what the last thing was that it was trying to reverse engineer?

[ErikEJ]

No, once you figure out (or share the full schema privately) I will try to address this with the EF Core team (lack of good error message)

[ErikEJ]

You could try to use the EF Core 7 command line tool, and run it with verbose logging.

[ErikEJ]

Any news?

[aespitia]

dbproject.zip
Yes, try this one the issue is with the no-pk table. it has an FK, but no PK. will update the db on our end to see if it fixes the issue for me to get past this.

[aespitia]

yes fixing the PK seems to fix it, the .net core 6 implementation does show the warning in the GUI over the table, but processes it fine

[ErikEJ]

@bricelam potential EF Core 7 issue?

[ErikEJ]

Could you share the EF 6 warning?

[aespitia]

i just meant that in the GUI of ef Core POwertools there's a warning sign (yellow triangle) on the table that has no PK. but it processes it anyway.

[ErikEJ]

@aespitia Unable to repro based on your latest .zip file

[ErikEJ]

Closing as no repro was provided

[blogcraft]

I happen to come across the same problem.

I have an app which uses some tables that don´t have a primary key.

When I do a reverse engineer with Ef Core 6, it works fine and generates the model correctly.

But when I choose Ef Core 7 the model generation fails with this error:

System.InvalidOperationException: Reverse engineer error: 
System.NullReferenceException: Object reference not set to an instance of an object.
   at string Microsoft.EntityFrameworkCore.Scaffolding.Internal.CSharpDbContextGenerator.TransformText()
   at string Microsoft.EntityFrameworkCore.Scaffolding.Internal.CSharpModelGenerator.ProcessTemplate(ITextTransformation transformation)
   at ScaffoldedModel Microsoft.EntityFrameworkCore.Scaffolding.Internal.CSharpModelGenerator.GenerateModel(IModel model, ModelCodeGenerationOptions options)
   at ScaffoldedModel RevEng.Core.ReverseEngineerScaffolder.ScaffoldModel(string connectionString, DatabaseModelFactoryOptions databaseOptions, ModelReverseEngineerOptions modelOptions, ModelCodeGenerationOptions codeOptions, bool removeNullableBoolDefaults, bool excludeNavigations, bool dbContextOnly, bool entitiesOnly, bool useSchemaFolders) in C:/Code/Github/EFCorePowerTools/src/GUI/RevEng.Core/ReverseEngineerScaffolder.cs:line 385
   at SavedModelFiles RevEng.Core.ReverseEngineerScaffolder.GenerateDbContext(ReverseEngineerCommandOptions options, List<string> schemas, string outputContextDir, string modelNamespace, string contextNamespace, string projectPath, string outputPath) in C:/Code/Github/EFCorePowerTools/src/GUI/RevEng.Core/ReverseEngineerScaffolder.cs:line 103
   at ReverseEngineerResult RevEng.Core.ReverseEngineerRunner.GenerateFiles(ReverseEngineerCommandOptions options) in C:/Code/Github/EFCorePowerTools/src/GUI/RevEng.Core/ReverseEngineerRunner.cs:line 88
   at async Task<int> EfReveng.Program.Main(string[] args) in C:/Code/Github/EFCorePowerTools/src/GUI/efreveng/Program.cs:line 69

   at ReverseEngineerResult EFCorePowerTools.Handlers.ReverseEngineer.ResultDeserializer.BuildResult(string output)
   at async Task<ReverseEngineerResult> EFCorePowerTools.Handlers.ReverseEngineer.EfRevEngLauncher.GetOutputAsync()
   at async Task<ReverseEngineerResult> EFCorePowerTools.Handlers.ReverseEngineer.EfRevEngLauncher.LaunchExternalRunnerAsync(ReverseEngineerOptions options, CodeGenerationMode codeGenerationMode, Project project)
   at async Task EFCorePowerTools.Handlers.ReverseEngineer.ReverseEngineerHandler.GenerateFilesAsync(Project project, ReverseEngineerOptions options, Tuple<bool, string> containsEfCoreReference, bool onlyGenerate)
   at async Task EFCorePowerTools.Handlers.ReverseEngineer.ReverseEngineerHandler.ReverseEngineerCodeFirstAsync(Project project, string optionsPath, bool onlyGenerate, bool fromSqlProj)

I suspect the problem has to do with the tables without primary key because when I remove those tables from the reverse engineer process, it works.

[blogcraft]

Digging around, it seems that the problem is related to this and not a Power tools Issue?

dotnet/efcore#29516

[ErikEJ]

@blogcraft correct. And will be fixed in 7.0.3

[aespitia]

yay! glad to know this issue helped someone