@craft-ts

Appearance

No dependency cycles ​

assertNoDependencyCycles checks directed depends-on edges between services, components and computeds:

ts
export function keepTheDependencyGraphAcyclic(graph: ArchitectureGraph) {
  assertNoDependencyCycles(graph.graph);
}

What it prevents ​

The obvious cycle is two services that construct each other:

text
Left → Right → Left

In source, it often appears as a harmless pair of yield* calls. At runtime it can fail as a recursive construction, an incomplete service or a provider that only breaks when a route is first visited.

The rule also catches a self-dependency and cycles involving computed values.

Shared dependencies are not cycles ​

This is valid:

text
AdminPage  → Auth
Checkout   → Auth

Both branches depend on a shared kernel; there is no path back from Auth to either branch. provides, contains, loads and renders are structural edges and are not treated as dependency cycles.

How to break a real cycle ​

Usually one side should depend on a smaller contract:

  • extract a read-only service from the two large services;
  • move shared policy into a third service;
  • pass a value as an input instead of resolving the owning service;
  • move a derived value into the consumer instead of publishing it back.

Do not silence a cycle by adding an allow list: this assertion has no such escape hatch because a cycle changes construction semantics.

See also ​