[BUG] PersistentAgentsClient.Messages.CreateMessageAsync fails with `InvalidCastException`

[crickman]

Library name and version

Azure.AI.Agents.Persistent 1.2.0-beta.4

Describe the bug

PersistentAgentsClient.Messages.CreateMessageAsync fails when providing an enumeration of MessageInputContentBlock.

Can be easily reproduced with an existing unit-test: Sample_PersistentAgents_ImageFileInputs.ImageFileInMessageExampleAsync

Is this test not running in your pipeline?

Expected behavior

Creates a message

Actual behavior

Throws exception due to a failed serialization

System.InvalidCastException: 
   at System.Text.Json.JsonSerializer.UnboxOnWrite[T](Object value)
   at System.Text.Json.Serialization.Metadata.JsonTypeInfo`1.SerializeAsObject(Utf8JsonWriter writer, Object rootValue)
   at System.Text.Json.JsonSerializer.WriteStringAsObject(Object value, JsonTypeInfo jsonTypeInfo)
   at Azure.AI.Agents.Persistent.ThreadMessages.CreateMessageAsync(String threadId, MessageRole role, IEnumerable`1 contentBlocks, IEnumerable`1 attachments, IReadOnlyDictionary`2 metadata, CancellationToken cancellationToken)

Reproduction Steps

Run your unit-test: Sample_PersistentAgents_ImageFileInputs.ImageFileInMessageExampleAsync

Environment

.NET 9.0

[nick863]

The Fix has merged, the next release (1.2.0-beta.5) will contain the fix. The issue is caused by the regression in the version 1.2.0-beta.4. The version 1.2.0-beta.3 should not contain this problem.

[crickman]

@nick863 - Amazing, appriate the quick fix!

[nick863]

The new version of Azure.AI.Agents.Persistent was released. Please upgrade using the next command.

dotnet add package Azure.AI.Agents.Persistent --version 1.2.0-beta.5