dotnet/orleans · error · InvalidOperationException

Cannot get events from a half-baked {nameof(AdoNetBatchConta

Error message

Cannot get events from a half-baked {nameof(AdoNetBatchContainer)}

What it means

Thrown by AdoNetBatchContainer.GetEvents<T>() when SequenceToken is null. A container built via the public constructor (used for sending) has no sequence token; only containers materialized from a stored message via FromMessage get a SequenceToken assigned. Calling GetEvents on a send-side container is invalid because there is no offset to anchor the events to.

Source

Thrown at src/AdoNet/Orleans.Streaming.AdoNet/AdoNetBatchContainer.cs:52

    [Id(3)]
    public EventSequenceTokenV2 SequenceToken { get; internal set; } = null!;

    /// <summary>
    /// Holds the receipt for message confirmation.
    /// </summary>
    [Id(4)]
    public int Dequeued { get; internal set; }

    #endregion Serialized State

    #region Interface

    StreamSequenceToken IBatchContainer.SequenceToken => SequenceToken;

    public IEnumerable<Tuple<T, StreamSequenceToken>> GetEvents<T>()
    {
        return SequenceToken is null
            ? throw new InvalidOperationException($"Cannot get events from a half-baked {nameof(AdoNetBatchContainer)}")
            : Events
                .OfType<T>()
                .Select((e, i) => Tuple.Create<T, StreamSequenceToken>(e, SequenceToken.CreateSequenceTokenForEvent(i)));
    }

    public bool ImportRequestContext()
    {
        if (RequestContext is not null)
        {
            RequestContextExtensions.Import(RequestContext);
            return true;
        }

        return false;
    }

    #endregion Interface

View on GitHub (pinned to fca799fa70)

Solutions

Only call GetEvents on containers obtained from the ADO.NET stream receiver (built via FromMessage, which sets SequenceToken).
In tests, set container.SequenceToken = new EventSequenceTokenV2(...) before calling GetEvents.
Do not reuse send-side containers (from ToMessagePayload) for event enumeration.

Example fix

// before (test/misuse)
var container = new AdoNetBatchContainer(streamId, events, null);
foreach (var ev in container.GetEvents<MyEvent>()) { } // SequenceToken null -> error

// after
container.SequenceToken = new EventSequenceTokenV2(0);
foreach (var ev in container.GetEvents<MyEvent>()) { }

Defensive patterns

Strategy: type-guard

Type guard

// Only enumerate events from receive-side containers (token set).
static bool IsReadyForEvents(AdoNetBatchContainer c) => c.SequenceToken is not null;

Try / catch

try { foreach (var e in container.GetEvents<T>()) { /* ... */ } }
catch (InvalidOperationException ex) when (ex.Message.Contains("half-baked"))
{
    // container was not materialized via FromMessage; log and skip.
}

Prevention

Treat AdoNetBatchContainer as receive-only for GetEvents; obtain it from the stream receiver.
In tests, always set SequenceToken before GetEvents.
Never reuse a send-side container (from ToMessagePayload) for enumeration.

When it happens

Trigger: GetEvents<T>() is invoked on an AdoNetBatchContainer whose SequenceToken was never set — i.e., one created by ToMessagePayload/new AdoNetBatchContainer rather than deserialized and stamped via FromMessage.

Common situations: Custom streaming code or tests that construct an AdoNetBatchContainer directly and call GetEvents; reflection/serialization round-trips that bypass FromMessage; misuse of an internal type outside its receive path.

Related errors

AI-assisted analysis of dotnet/orleans@fca799fa70 (2026-08-13). Data as JSON: /api/errors/1997d6dac1c58f9a. Report an issue: GitHub.