feat(dependencies): add GetAllEventsDependingOnProbe

Add a new method to the Manager that retrieves all events depending on a
specified probe, including both direct and transitive dependents.
This functionality is accompanied by comprehensive unit tests to cover
various success and error scenarios.

Co-authored-by: Raphael Campos <[email protected]>

Author: geyslan

pkg/events/dependencies/manager.go

@@ -97,6 +97,50 @@ func (m *Manager) GetProbe(handle probes.Handle) (*ProbeNode, error) {
 	return probeNode, nil
 }
 
+// GetAllEventsDependingOnProbe returns all events that transitively depend on the given probe.
+// This includes direct dependents and all events that depend on those dependents recursively.
+func (m *Manager) GetAllEventsDependingOnProbe(handle probes.Handle) ([]events.ID, error) {
+	m.mu.RLock()
+	defer m.mu.RUnlock()
+
+	probeNode := m.getProbe(handle)
+	if probeNode == nil {
+		return nil, ErrNodeNotFound
+	}
+
+	return m.collectAllEventDependents(probeNode.GetDependents()), nil
+}
+
+// collectAllEventDependents computes the transitive closure of event dependents via depth-first traversal.
+func (m *Manager) collectAllEventDependents(startEvents []events.ID) []events.ID {
+	visited := make(map[events.ID]struct{}, len(startEvents))
+	result := make([]events.ID, 0, len(startEvents))
+
+	var collect func(events.ID)
+	collect = func(id events.ID) {
+		if _, seen := visited[id]; seen {
+			return
+		}
+
+		visited[id] = struct{}{}
+		result = append(result, id)
+
+		// Get the event node and recursively process all dependents
+		if node := m.getEventNode(id); node != nil {
+			for _, dep := range node.GetDependents() {
+				collect(dep)
+			}
+		}
+	}
+
+	// Start collection from each initial event
+	for _, id := range startEvents {
+		collect(id)
+	}
+
+	return result
+}
+
 // SelectEvent adds the given event to the management tree with default dependencies
 // and marks it as explicitly selected.
 // It also recursively adds all events that this event depends on (its dependencies) to the tree.