Efcore: Can't remove migration after adding

[glatzert]

dotnet ef migrations remove
after
dotnet ef migrations add

throws the following exception.

Exception message:
Login failed for user 'DOMAIN\myUserName'.
Stack trace:
System.Data.SqlClient.SqlException (0x80131904): Login failed for user 'DOMAIN\myUserName'.
   at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, Boolean redirectedUserInstance, SqlConnectionString userConnectionOptions, SessionData reconnectSessionData, Boolean applyTransientFaultHandling)
   at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, DbConnectionPoolKey poolKey, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection, DbConnectionOptions userOptions)
   at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnectionPool pool, DbConnection owningObject, DbConnectionOptions options, DbConnectionPoolKey poolKey, DbConnectionOptions userOptions)
   at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
   at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject, DbConnectionOptions userOptions, DbConnectionInternal oldConnection)
   at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, UInt32 waitForMultipleObjectsTimeout, Boolean allowCreate, Boolean onlyOneCheckConnection, DbConnectionOptions userOptions, DbConnectionInternal& connection)
   at System.Data.ProviderBase.DbConnectionPool.TryGetConnection(DbConnection owningObject, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal& connection)
   at System.Data.ProviderBase.DbConnectionFactory.TryGetConnection(DbConnection owningConnection, TaskCompletionSource`1 retry, DbConnectionOptions userOptions, DbConnectionInternal oldConnection, DbConnectionInternal& connection)
   at System.Data.ProviderBase.DbConnectionInternal.TryOpenConnectionInternal(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
   at System.Data.ProviderBase.DbConnectionClosed.TryOpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory, TaskCompletionSource`1 retry, DbConnectionOptions userOptions)
   at System.Data.SqlClient.SqlConnection.TryOpen(TaskCompletionSource`1 retry)
   at System.Data.SqlClient.SqlConnection.Open()
   at Microsoft.EntityFrameworkCore.Storage.RelationalConnection.Open(Boolean errorsExpected)
   at Microsoft.EntityFrameworkCore.Storage.Internal.SqlServerDatabaseCreator.<>c__DisplayClass18_0.<Exists>b__0(DateTime giveUp)
   at Microsoft.EntityFrameworkCore.ExecutionStrategyExtensions.<>c__DisplayClass12_0`2.<Execute>b__0(DbContext c, TState s)
   at Microsoft.EntityFrameworkCore.Storage.Internal.SqlServerExecutionStrategy.Execute[TState,TResult](TState state, Func`3 operation, Func`3 verifySucceeded)
   at Microsoft.EntityFrameworkCore.ExecutionStrategyExtensions.Execute[TState,TResult](IExecutionStrategy strategy, Func`2 operation, Func`2 verifySucceeded, TState state)
   at Microsoft.EntityFrameworkCore.ExecutionStrategyExtensions.Execute[TState,TResult](IExecutionStrategy strategy, TState state, Func`2 operation)
   at Microsoft.EntityFrameworkCore.Storage.Internal.SqlServerDatabaseCreator.Exists(Boolean retryOnNotExists)
   at Microsoft.EntityFrameworkCore.Storage.Internal.SqlServerDatabaseCreator.Exists()
   at Microsoft.EntityFrameworkCore.Migrations.HistoryRepository.Exists()
   at Microsoft.EntityFrameworkCore.Migrations.HistoryRepository.GetAppliedMigrations()
   at Microsoft.EntityFrameworkCore.Migrations.Design.MigrationsScaffolder.RemoveMigration(String projectDir, String rootNamespace, Boolean force)
   at Microsoft.EntityFrameworkCore.Design.Internal.MigrationsOperations.RemoveMigration(String contextType, Boolean force)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.RemoveMigrationImpl(String contextType, Boolean force)
   at Microsoft.EntityFrameworkCore.Design.OperationExecutor.RemoveMigration.<>c__DisplayClass0_1.<.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)
ClientConnectionId:b1cba61c-c324-413d-a208-b08d0ea890c1
Error Number:18456,State:1,Class:14

Since I was able to _create_ the Migration, I'd assume to be able to remove it again as well.

Steps to reproduce

• Add Migration for database, where you have no Access rights.
• Remove Migration again

Further technical details

EF Core version: 2.0.1
Database Provider: Microsoft.EntityFrameworkCore.SqlServer
Operating system: Win10-x64
IDE: cmd.exe

[smitpatel]

Add migration does not need connection to database since it is only computing difference between current model & model from last migration (stored in modelsnapshot).
Whereas remove migration needs connection to database because it needs to verify that you are not reverting a migration which is already been applied to database. If the migration is already being applied to database then you first need to "unapply" the migration on database first before removing. This is necessary. If we remove a migration which is already applied to database then your database is out of sync with migrations causing failures in any subsequent operation.

[ajcvickers]

To add to what @smitpatel said above, there is also a "force" command line option that can be used to force the remove even if the database cannot be reached.

[glatzert]

Thanks for making the decision clear and mentioning the force Switch :)