Struct DeadlockDetector 

pub struct DeadlockDetector;

Deadlock detector for workflow analysis.

Provides static analysis of workflow structure to detect:

• Dependency cycles (hard error - prevents execution)
• Resource deadlock patterns (warning - execution continues)
• Long dependency chains (warning - execution continues)

Implementations

impl DeadlockDetector

pub fn new() -> Self

Creates a new deadlock detector.

pub fn detect_dependency_cycles( &self, workflow: &Workflow, ) -> Result<(), DeadlockError>

Detects dependency cycles in the workflow DAG.

Uses Tarjan’s strongly connected components algorithm to find cycles. A cycle indicates tasks that directly or indirectly depend on each other, making execution impossible.

Arguments

• workflow - The workflow to analyze

Returns

• Ok(()) if no cycles detected
• Err(DeadlockError::DependencyCycle) with cycle path if cycle found

Example

let detector = DeadlockDetector::new();
if let Err(e) = detector.detect_dependency_cycles(&workflow) {
    println!("Cycle detected: {:?}", e);
}

pub fn detect_resource_deadlocks( &self, workflow: &Workflow, ) -> Result<Vec<DeadlockWarning>, DeadlockError>

Analyzes workflow for potential resource deadlocks.

This is a heuristic analysis that generates warnings for:

1. Tasks that might share resources (no direct access in our model)
2. Long chains of dependent tasks (timeout risk)
3. Tasks with no timeout (hang risk)

Note: This function does NOT prevent execution - warnings are informational.

Arguments

• workflow - The workflow to analyze

Returns

Vector of deadlock warnings (may be empty)

Example

let detector = DeadlockDetector::new();
let warnings = detector.detect_resource_deadlocks(&workflow)?;
for warning in warnings {
    println!("Warning: {}", warning.description());
}

pub fn validate_workflow( &self, workflow: &Workflow, ) -> Result<Vec<DeadlockWarning>, DeadlockError>

Validates that a workflow is deadlock-free.

This is a convenience method that combines cycle detection and resource deadlock analysis.

Arguments

• workflow - The workflow to validate

Returns

• Ok(Vec<DeadlockWarning>) - Warnings (may be empty) if no hard errors
• Err(DeadlockError::DependencyCycle) - If cycle detected

Example

let detector = DeadlockDetector::new();
match detector.validate_workflow(&workflow) {
    Ok(warnings) => {
        for warning in warnings {
            println!("Warning: {}", warning.description());
        }
        // Execute workflow
    }
    Err(e) => {
        eprintln!("Cannot execute: {}", e);
    }
}

Trait Implementations

impl Default for DeadlockDetector

fn default() -> Self

Returns the “default value” for a type.