MySQL Bugs: #116381: System.NullReferenceException after upgrade to net8

Bug #116381	System.NullReferenceException after upgrade to net8
Submitted:	16 Oct 2024 16:39	Modified:	17 Oct 2024 8:42
Reporter:	Neil Scales	Email Updates:
Status:	Unsupported	Impact on me:	None
Category:	Connector / NET	Severity:	S3 (Non-critical)
Version:	8.0.10	OS:	Any
Assigned to:		CPU Architecture:	Any
Tags:	C#, DDL, migration, NET

Description:
I get the exception below after upgrading to .net8 from net 6.  This is during a migration, doesn't matter if I drop the schema.
I have around 300 tables, so have no idea which table is causing the problem.

Message: 
System.NullReferenceException : Object reference not set to an instance of an object.

  Stack Trace: 
RelationalTypeMappingSource.FindCollectionMapping(RelationalTypeMappingInfo info, Type modelType, Type providerType, CoreTypeMapping elementMapping)
<>c.<FindMappingWithConversion>b__8_0(ValueTuple`4 k, RelationalTypeMappingSource self)
ConcurrentDictionary`2.GetOrAdd[TArg](TKey key, Func`3 valueFactory, TArg factoryArgument)
RelationalTypeMappingSource.FindMappingWithConversion(RelationalTypeMappingInfo mappingInfo, Type providerClrType, ValueConverter customConverter)
RelationalTypeMappingSource.FindMappingWithConversion(RelationalTypeMappingInfo mappingInfo, IReadOnlyList`1 principals)
RelationalTypeMappingSource.FindMapping(IProperty property)
<>c.<get_TypeMapping>b__94_0(IProperty property)
NonCapturingLazyInitializer.EnsureInitialized[TParam,TValue](TValue& target, TParam param, Func`2 valueFactory)
Property.get_TypeMapping()
IReadOnlyProperty.FindTypeMapping()
RelationalPropertyExtensions.FindRelationalTypeMapping(IReadOnlyProperty property)
RelationalPropertyExtensions.GetColumnType(IReadOnlyProperty property)
RelationalPropertyExtensions.GetColumnType(IProperty property)
RelationalModel.CreateDefaultColumnMapping(ITypeBase typeBase, ITypeBase mappedType, TableBase defaultTable, TableMappingBase`1 tableMapping, Boolean isTph, Boolean isTpc)
RelationalModel.AddDefaultMappings(RelationalModel databaseModel, IEntityType entityType, IRelationalTypeMappingSource relationalTypeMappingSource)
RelationalModel.Create(IModel model, IRelationalAnnotationProvider relationalAnnotationProvider, IRelationalTypeMappingSource relationalTypeMappingSource, Boolean designTime)
RelationalModel.Add(IModel model, IRelationalAnnotationProvider relationalAnnotationProvider, IRelationalTypeMappingSource relationalTypeMappingSource, Boolean designTime)
RelationalModelRuntimeInitializer.InitializeModel(IModel model, Boolean designTime, Boolean prevalidation)
ModelRuntimeInitializer.Initialize(IModel model, Boolean designTime, IDiagnosticsLogger`1 validationLogger)
Migrator.FinalizeModel(IModel model)
Migrator.GenerateUpSql(Migration migration, MigrationsSqlGenerationOptions options)
MySQLMigrator.GenerateUpSql(Migration migration, MigrationsSqlGenerationOptions options)
<>c__DisplayClass16_2.<GetMigrationCommandLists>b__2()
Migrator.Migrate(String targetMigration)
RelationalDatabaseFacadeExtensions.Migrate(DatabaseFacade databaseFacade)

Any pointers on how to narrow down the issue would be useful.

How to repeat:
.

HI Mr. Scales,

Thank you for your bug report.

However, 8.0.10 is a VERY old release, both for our Server and C/NET.

Can you first try to upgrade your MySQL server to 8.0.40. Before you do, please take a backup.

Then switch to C/NET 8.0.40 and try again.

If you have problems with 8.0.40, on both client and server sides, please let us know.
 
Unsupported.

8.0.10 is the latest entity framework core package.

I've also update the MySql specific packages to the latest versions:

  "MySql.Data" Version="9.1.0"
  "MySql.EntityFrameworkCore" Version="8.0.8"

I still get the same stack trace.

Hi Mr. Scales,

It turns out this is not true.

Even Connector/NET 9.1.0 is EntityFrameworkCore release.

https://dev.mysql.com/doc/connector-net/en/connector-net-entity-framework.html

Please, upgrade your C/NET too .....

Then, if you get the same problem with MySQL Server 8.0.40 and C/NET 8.0.40, then send us your program so that we can try to repeat it ......