.NET 5.0, Preview 4. Enum_Constraint repeats three times. Update-Database fails

[henrikdahl8240]

Update-Database fails with the information:

PM> Update-Database -Context XXX_DbContext -Project XXX.Migrations -StartupProject XXX
Build started...
Build succeeded.
fail: Microsoft.EntityFrameworkCore.Database.Command[20102]
      Failed executing DbCommand (18ms) [Parameters=[], CommandType='Text', CommandTimeout='600']
      ALTER TABLE [L].[MyTable] ADD CONSTRAINT [CK_MyTable_MyColumn_Enum_Constraint] CHECK ([MyColumn] IN(0, 1, 2));
Failed executing DbCommand (18ms) [Parameters=[], CommandType='Text', CommandTimeout='600']
ALTER TABLE [L].[MyTable] ADD CONSTRAINT [CK_MyTable_MyColumn_Enum_Constraint] CHECK ([MyColumn] IN(0, 1, 2));
Microsoft.Data.SqlClient.SqlException (0x80131904): There is already an object named 'CK_MyTable_MyColumn_Enum_Constraint' in the database.
Could not create constraint or index. See previous errors.
   at Microsoft.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at Microsoft.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction)
   at Microsoft.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose)
   at Microsoft.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady)
   at Microsoft.Data.SqlClient.SqlCommand.RunExecuteNonQueryTds(String methodName, Boolean isAsync, Int32 timeout, Boolean asyncWrite)
   at Microsoft.Data.SqlClient.SqlCommand.InternalExecuteNonQuery(TaskCompletionSource`1 completion, Boolean sendToPipe, Int32 timeout, Boolean& usedCache, Boolean asyncWrite, Boolean inRetry, String methodName)
   at Microsoft.Data.SqlClient.SqlCommand.ExecuteNonQuery()
   at Microsoft.EntityFrameworkCore.Storage.RelationalCommand.ExecuteNonQuery(RelationalCommandParameterObject parameterObject)
   at Microsoft.EntityFrameworkCore.Migrations.MigrationCommand.ExecuteNonQuery(IRelationalConnection connection, IReadOnlyDictionary`2 parameterValues)
   at Microsoft.EntityFrameworkCore.Migrations.Internal.MigrationCommandExecutor.ExecuteNonQuery(IEnumerable`1 migrationCommands, IRelationalConnection connection)
   at Microsoft.EntityFrameworkCore.Migrations.Internal.Migrator.Migrate(String targetMigration)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.UpdateDatabase(String targetMigration, String connectionString, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.UpdateDatabaseImpl(String targetMigration, String connectionString, String contextType)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.UpdateDatabase.<>c__DisplayClass0_0.<.ctor>b__0()
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.OperationBase.Execute(Action action)
ClientConnectionId:d4f9b048-76a6-4274-8abb-97bca4430e91
Error Number:2714,State:5,Class:16
There is already an object named 'CK_MyTable_MyColumn_Enum_Constraint' in the database.
Could not create constraint or index. See previous errors.
PM> 

Using Script-Migrations I can observe, that there are three occurrences of:
ALTER TABLE [MySchema].[MyTable] ADD CONSTRAINT [CK_MyTable_MyColumn_Enum_Constraint] CHECK ([MyColumn] IN(0, 1, 2));

I have tried to check approximately 10 different ALTER TABLE [MySchema].[MyTable] ADD CONSTRAINT [CK_..._..._Enum_Constraint] CHECK ([.] IN(...)); statements.They were all repeated 3 times each.

Is there an error in EF Core 5.0 Preview 4 that these ...Enum_Constraint constraints are simply repeated three times and I just need to wait for Preview 5.

[henrikdahl8240]

I have noticed, that there are also situations, where the creation of the constraint is not being repeated.

[roji]

@henrikdahl8240 in that case, can you please post a small, runnable code sample which triggers the repetition?

[henrikdahl8240]

@roji In order to continue, I decided to remove the migrations added by former versions, simply by removing the files and folders in the Migrations folder. Afterwards I got stuck by #21010 (comment).
Therefore I don't know, if there are still generated multiple definitions. If the problems persist after I overcome the too long name of constraint issue, I will obviously aim to post such a small sample as you request.

[ajcvickers]

Duplicate of #18958. Note however that automatic generation of these constraints has been removed from 5.0 and moved to an external package--see #20897.