cycle_detection

README

Cycle Detection Example

This example demonstrates how gioc detects circular dependencies both at build-time and at runtime.

What it demonstrates

• Build-time validation with c.Validate() – catches cycles before any resolution
• Runtime detection – panics with a clear cycle path if Validate() was skipped
• A valid dependency chain for comparison

Code explanation

Circular dependency

ServiceA -> ServiceB -> ServiceA  (cycle!)

ServiceA's constructor takes *ServiceB, and ServiceB's constructor takes *ServiceA. This creates an unresolvable cycle.

Build-time detection (recommended)

Call c.Validate() after all registrations. It performs a DFS on the dependency graph and reports cycles as an error – no panic, no partial initialization.

Runtime detection (fallback)

If Validate() is not called, the container tracks the resolution path during Resolve. When a type appears twice in the path, it panics with the full cycle path.

Valid chain

Database -> Repository -> Service  (no cycle)

This resolves successfully, demonstrating that non-cyclic graphs work as expected.

Output

=== Build-time Validation ===
Validation caught the problem:
  gioc: validation failed:
  circular dependency: *main.ServiceA -> *main.ServiceB -> *main.ServiceA

=== Runtime Detection ===
Runtime panic: gioc: circular dependency detected: *main.ServiceA -> *main.ServiceB -> *main.ServiceA

=== Valid Dependency Chain ===
Service resolved: &{repo:0x...}
Database connection: localhost:5432