langgraph 0.3.15

Summary of Changes

• Added more efficient channel availability checks through new is_available() method on all channel types #3890
• Simplified branch mechanism in StateGraph with unified channel naming #3891
• Improved performance in Pregel task creation and execution #3893

Detailed Changes

langgraph.channels.base.BaseChannel

• Added new is_available() method to check if a channel has values without having to catch exceptions #3890

All Channel Types

• Refactored all channel implementations to use a MISSING sentinel value instead of attribute errors for tracking empty state #3890
• Added efficient is_available() implementations to:
  • AnyValue
  • BinaryOperatorAggregate
  • DynamicBarrierValue
  • EphemeralValue
  • LastValue
  • NamedBarrierValue
  • Topic
  • UntrackedValue

langgraph.graph.state.StateGraph

• Simplified branch mechanism by using a single universal channel pattern branch:to:{node} instead of complex channel names #3891
• Improved efficiency by creating a single branch channel for each node rather than one for each potential branch destination #3891

langgraph.pregel.algo

• Improved performance by adding dedicated checkpoint_null_version() and _triggers() helper functions #3893
• Enhanced task creation efficiency by using binascii.unhexlify instead of UUID parsing #3893
• Optimized memory usage with single tuple constant for push triggers instead of creating new lists #3893
• Updated to use the new channel is_available() method instead of exception handling #3890

langgraph.pregel.io

• Removed return_exception parameter from read_channel() as it's no longer needed with the new availability checking #3890
• Updated branch channel name handling to use the simplified naming convention #3891

langgraph.types

• Changed PregelExecutableTask.triggers type from list[str] to more flexible Sequence[str] for better performance #3893