Document tooling workaround for projects targeting x86

[twojnarowski]

File a bug

When setting a WinForms project with <PlatformTarget>x86</PlatformTarget> I cannot add a migration because of the following error: Could not load assembly 'EFCorex86MigrationFail'. Ensure it is referenced by the startup project 'EFCorex86MigrationFail'.. That happens when Context is in the startup project. When having a solution where Context is in a separate project, this error happens: System.IO.FileNotFoundException: Could not load file or assembly 'EFCorex86MigrationFail, Culture=neutral, PublicKeyToken=null'.

Include your code

Reproduction: https://github.com/twojnarowski/EFCorex86MigrationFail Steps: Create WinForms app on .NET8, add 3 EF Core nugets - Design, Tools and SQLServer. Create a Context class. Run add-migration command - everything works. Change project settings to target platform x86, run add-migration, migration fails.

Include verbose output

Issue when Context in Startup Project:

PM> add-migration InitialMigration
Build started...
Build succeeded.
Could not load assembly 'EFCorex86MigrationFail'. Ensure it is referenced by the startup project 'EFCorex86MigrationFail'.

Issue when Context in a separate project:

PM> add-migration InitialMigration -context EFContext
Build started...
Build succeeded.
System.IO.FileNotFoundException: Could not load file or assembly 'EFCorex86MigrationFail, Culture=neutral, PublicKeyToken=null'. Nie można odnaleźć określonego pliku.
File name: 'EFCorex86MigrationFail, Culture=neutral, PublicKeyToken=null'
   at System.Reflection.RuntimeAssembly.InternalLoad(AssemblyName assemblyName, StackCrawlMark& stackMark, AssemblyLoadContext assemblyLoadContext, RuntimeAssembly requestingAssembly, Boolean throwOnFileNotFound)
   at System.Reflection.Assembly.Load(AssemblyName assemblyRef)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.get_StartupAssembly()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.get_MigrationsOperations()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigrationImpl(String name, String outputDir, String contextType, String namespace)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.AddMigration.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.<>c__DisplayClass3_0`1.<Execute>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
Could not load file or assembly 'EFCorex86MigrationFail, Culture=neutral, PublicKeyToken=null'. Nie można odnaleźć określonego pliku.

Include provider and version information

EF Core version: 8.0.11 Database provider: Microsoft.EntityFrameworkCore.SqlServer Target framework: NET 8.0 Operating system: Windows 11 IDE: Visual Studio 2022 17.4

Workaround:

Set project back to Any CPU, create migration, update database. Return project back to x86, everything works.