Error Codes

NPipeline error codes follow the pattern NPxxxx where the first two digits indicate the category.

NP01xx - Core Pipeline Errors

Code	Name	Description
NP0101	PipelineRequiresAtLeastOneNode	A pipeline must have at least one node. Add at least one source, transform, or sink.
NP0102	NodeMissingInputConnection	A non-source node has no input connection. Connect an upstream node to it.
NP0103	CyclicDependencyDetected	The pipeline graph contains a cycle. NPipeline requires a directed acyclic graph (DAG).
NP0104	NodeAlreadyAdded	A node with this ID has already been added to the builder. Use a unique ID.
NP0105	NodeNameNotUnique	A node with this name already exists. Choose a different name.

NP02xx - Type System Errors

Code	Name	Description
NP0201	TypeMismatchInConnection	Output type of the source node doesn't match input type of the target node.
NP0202	InputDataStreamWrongType	The input data stream is not of the expected type. Check node type parameters.
NP0203	CannotRegisterMappingsAfterExecution	Mapping registrations must happen before pipeline execution begins.
NP0204	RecordTypeHasNoPublicConstructor	The target record type has no public constructors. Add a public constructor.
NP0205	InvalidMemberAccessExpression	The member selector expression is invalid. Use a simple property accessor.
NP0206	MemberNotWritable	The target member is read-only. Use a writable property or constructor parameter.
NP0207	SetterCreationFailed	Failed to create a setter for the specified member via reflection.
NP0208	ValueTupleConstructorNotFound	Could not find the expected ValueTuple constructor.
NP0210	CannotConcatenateStreamsTypeMismatch	Cannot concatenate data streams of different types.

NP03xx - Node Execution Errors

Code	Name	Description
NP0301	NodeKindNotSupported	The node kind is not supported or its execution delegate was not bound.
NP0302	OutputNotFoundForSourceNode	Could not locate the output data stream for a source node.
NP0303	PipelineExecutionFailedAtNode	Execution failed at a specific node. Check the NodeId in the exception.
NP0304	PipelineExecutionFailed	The pipeline execution failed. Check the inner exception for details.
NP0305	ItemFailedAfterMaxRetries	An item failed to process after all retry attempts were exhausted.
NP0306	ErrorHandlingFailed	The error handler itself threw an exception.
NP0307	LineageCardinalityMismatch	The number of lineage inputs doesn't match the number of outputs. Internal framework error.
NP0308	FailedToExtractItemsFromInMemoryDataStream	Could not extract items from an InMemoryDataStream. Internal framework error.
NP0310	CircuitBreakerTripped	The circuit breaker tripped after the configured threshold of consecutive failures.
NP0311	RetryLimitExhausted	All retry attempts were exhausted.

NP04xx - Configuration and Setup Errors

Code	Name	Description
NP0401	ExecutionStrategyCannotBeSetForNonTransformNode	Execution strategies can only be applied to transform nodes.
NP0402	NodeNotFoundInBuilder	The referenced node was not found in the pipeline builder.
NP0403	ResilienceCannotBeAppliedToNonTransformNode	Resilience policies can only be applied to transform nodes.
NP0404	InvalidErrorHandlerType	The error handler type doesn't implement the required interface.
NP0405	PreConfiguredInstanceAlreadyAdded	A pre-configured instance for this node has already been registered.
NP0406	PreConfiguredInstanceNodeNotFound	The node for the pre-configured instance was not found in the builder.
NP0407	MergeStrategyNotSupported	The specified merge strategy is not supported.
NP0408	NodeActivationFailed	Could not instantiate the node type. Check constructors and DI registrations.
NP0411	JoinNodeRequiresTwoKeySelectorAttributes	Join nodes require exactly two [KeySelector] attribute declarations.
NP0412	UnbatchingNodeNotSupported	UnbatchingNode cannot be executed directly; use the unbatching execution strategy.
NP0413	BatchingNodeNotSupported	BatchingNode doesn't support per-item transformation; use the batching execution strategy.
NP0414	CustomMergeNodeMissingInterface	The custom merge node is missing the required interface implementation.
NP0415	UnbatchingExecutionStrategyMissingDeadLetterHandler	The unbatching strategy requires a dead letter handler when resilience is enabled.
NP0416	LineageAdapterMissing	Internal: lineage adapter not configured.
NP0417	SourceNodeLineageUnwrapMissing	Internal: source node lineage unwrap delegate not configured.
NP0418	SinkNodeLineageUnwrapMissing	Internal: sink node lineage unwrap delegate not configured.
NP0419	MissingTypeMetadata	Internal: node is missing type metadata.
NP0420	TimeWindowAssignerCannotBeNull	The time window assigner cannot be null for time-windowed operations.

NP05xx - Resource Management Errors

Code	Name	Description
NP0501	ContextDisposalFailed	One or more errors occurred while disposing pipeline context resources.
NP0502	DeadLetterQueueCapacityExceeded	The dead letter queue has reached its capacity limit.
NP0503	MaterializationCapExceeded	The materialization cap was exceeded. Increase MaxMaterializedItems or reduce data volume.
NP0504	BatchSizeMustBeGreaterThanZero	Batch size must be a positive integer.

Next Steps

• Build-Time Analyzers - build-time diagnostic rules
• Common Issues - symptom-based troubleshooting