Bug #104631 MySql.Data unable to load in .NET 5.0 target application
Submitted: 16 Aug 4:22 Modified: 17 Aug 3:32
Reporter: Scot McPherson Email Updates:
Status: Closed Impact on me:
None 
Category:Connector / NET Severity:S1 (Critical)
Version:8.0.23 OS:Microsoft Windows (Win10 20H2)
Assigned to: CPU Architecture:Other (Ryzen7)
Tags: .NET 5.0

[16 Aug 4:22] Scot McPherson
Description:
When using MySql.Data in a .NET 5.0 targeted project, the DLL is readable in the object viewer and the application compiles just fine, however when one tries to load the application, the first execution that requires use of MySql.Data causes an error to be thrown. It does not matter whether I use Nuget Package Management in Visual Studio, download and compile in Visual Studio, or download and compile using .NET 5.0 SDK command line "dotnet build". I have even removed the test projects, and manually forced .NET5.0 targeting in the MySql.Data.csproj file. No matter how I approach this, I cannot get the application to load MySql.Data.dll.

It works just fine when my projects target .Net 4.? Framework, just not .NET core frameworks. I require .NET 5.0 for this project.

---Begin Error---

System.Reflection.ReflectionTypeLoadException: Unable to load one or more of the requested types.
                                 Could not load file or assembly 'MySql.Data, Version=8.0.26.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d'. The system cannot find the file specified.
                                    at System.Reflection.RuntimeModule.GetTypes(RuntimeModule module)
                                    at System.Reflection.RuntimeModule.GetTypes()
                                    at System.Reflection.Assembly.GetTypes()
                                    at DarkRift.Server.PluginFactory.AddFile(String file, DependencyResolutionStrategy dependencyResolutionStrategy, String searchedDirectory) in C:\Users\scotm\Desktop\Unity\DarkRift 2.10.1 Sources\DarkRift.Server\PluginFactory.cs:line 164
                                 System.IO.FileNotFoundException: Could not load file or assembly 'MySql.Data, Version=8.0.26.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d'. The system cannot find the file specified.
                                 File name: 'MySql.Data, Version=8.0.26.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d'
[Error]   PluginFactory         Additional exception detail from LoaderExceptions property:
                                 System.IO.FileNotFoundException: Could not load file or assembly 'MySql.Data, Version=8.0.26.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d'. The system cannot find the file specified.
                                 File name: 'MySql.Data, Version=8.0.26.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d'
[Info]    PluginManager         Loaded plugin DatabaseProxy version 1.0.0
Unhandled exception. System.Reflection.TargetInvocationException: Exception has been thrown by the target of an invocation.
 ---> System.IO.FileNotFoundException: Could not load file or assembly 'MySql.Data, Version=8.0.26.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d'. The system cannot find the file specified.
File name: 'MySql.Data, Version=8.0.26.0, Culture=neutral, PublicKeyToken=c5687fc88969c44d'
   at MySQLConnector.MySQLConnect.CreateTables()
   at MySQLConnector.MySQLConnect..ctor(PluginLoadData pluginLoadData)
   --- End of inner exception stack trace ---
   at System.RuntimeMethodHandle.InvokeMethod(Object target, Object[] arguments, Signature sig, Boolean constructor, Boolean wrapExceptions)
   at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
   at System.RuntimeType.CreateInstanceImpl(BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture)
   at System.Activator.CreateInstance(Type type, BindingFlags bindingAttr, Binder binder, Object[] args, CultureInfo culture, Object[] activationAttributes)
   at System.Activator.CreateInstance(Type type, Object[] args)
   at DarkRift.Server.PluginFactory.Create[T](Type type, PluginBaseLoadData loadData, PluginLoadData backupLoadData) in C:\Users\scotm\Desktop\Unity\DarkRift 2.10.1 Sources\DarkRift.Server\PluginFactory.cs:line 249
   at DarkRift.Server.PluginManagerBase`1.LoadPlugin(String name, Type type, PluginBaseLoadData pluginLoadData, PluginLoadData backupLoadData, Boolean createResourceDirectory) in C:\Users\scotm\Desktop\Unity\DarkRift 2.10.1 Sources\DarkRift.Server\PluginManagerBase.cs:line 62
   at DarkRift.Server.ExtendedPluginManagerBase`1.LoadPlugin(String name, Type type, PluginBaseLoadData pluginLoadData, PluginLoadData backupLoadData, Boolean createResourceDirectory) in C:\Users\scotm\Desktop\Unity\DarkRift 2.10.1 Sources\DarkRift.Server\ExtendedPluginManagerBase.cs:line 55
   at DarkRift.Server.PluginManager.LoadPlugins(PluginsSettings settings) in C:\Users\scotm\Desktop\Unity\DarkRift 2.10.1 Sources\DarkRift.Server\PluginManager.cs:line 103
   at DarkRift.Server.DarkRiftServer..ctor(ServerSpawnData spawnData, ClusterSpawnData clusterSpawnData) in C:\Users\scotm\Desktop\Unity\DarkRift 2.10.1 Sources\DarkRift.Server\DarkRiftServer.cs:line 355
   at DarkRift.Server.DarkRiftServer..ctor(ServerSpawnData spawnData) in C:\Users\scotm\Desktop\Unity\DarkRift 2.10.1 Sources\DarkRift.Server\DarkRiftServer.cs:line 189
   at DarkRift.Server.Console.Program.Main(String[] args) in C:\Users\scotm\Desktop\Unity\DarkRift 2.10.1 Sources\DarkRift.Server.Console\Program.cs:line 124

How to repeat:
Write any code that relies on using MySql.Data.MySqlClient namespace that targets .NET 5.0
[17 Aug 3:32] Scot McPherson
Closing this issue, it seems it's a peculiarity with chained loading of libraries in .NET Core, and has nothing to do with MySQL.

Essentially, I have a base app which accepts plugin DLLs. When one write a plugin that relies on an external DLL, the base app can't find it. The bug belongs to that server project, not to MySQL Projects.