Diagnostics Suite

The :diagnostics module contains long-running safety and performance checks for the Summon runtime and backend integrations.

What is covered?

• Callback leak detection – verifies that hydration callbacks are cleared after every render.
• Router isolation – ensures router instances and renderers remain thread-local.
• Reactive blocking guard – installs BlockHound to fail tests when blocking APIs are invoked on Reactor threads.
• Hydration stress tests – runs repeated concurrent hydrated renders to surface race conditions.
• Renderer benchmarks – optional JMH benchmarks that capture the steady-state cost of server rendering.

Running the suite

# Run the diagnostic tests (JUnit 5 + BlockHound)
./gradlew :diagnostics:test

# Run the JMH micro-benchmarks
./gradlew :diagnostics:jmh

The benchmarking step is disabled by default; invoke the jmh task explicitly when you need throughput metrics.

The diagnostics module depends on :summon-core, so any runtime change will automatically flow into the safety and performance checks above.