Module plan_validation 

Pure validation functions for plan execution.

Shared between SQLite PlanExecutor and Neo4j Neo4jPlanExecutor. All functions are stateless — no database access.

Functions

detect_circular_dependencies

Detect circular dependencies using Tarjan’s SCC algorithm.

tarjan_scc

Tarjan’s algorithm for finding strongly connected components.

validate_batch_single_doing

Validate that at most one task in the batch has status=‘doing’.

validate_dependencies

Validate that all dependency references exist within the plan.