completed phase 2b

internal/domain/ci/dag.go

@@ -0,0 +1,78 @@
+package ci
+
+import "fmt"
+
+// dagNode holds a job name and its resolved dependencies.
+type dagNode struct {
+	name  string
+	needs []string
+}
+
+// TopoSort returns the job names in a valid topological execution order.
+// Returns an error if the dependency graph has cycles or references unknown jobs.
+func TopoSort(jobs map[string]WorkflowJob) ([]string, error) {
+	nodes := make(map[string]*dagNode, len(jobs))
+	for name, job := range jobs {
+		nodes[name] = &dagNode{name: name, needs: []string(job.Needs)}
+	}
+	// Validate all dependencies exist.
+	for _, node := range nodes {
+		for _, dep := range node.needs {
+			if _, ok := nodes[dep]; !ok {
+				return nil, fmt.Errorf("job %q depends on unknown job %q", node.name, dep)
+			}
+		}
+	}
+
+	var order []string
+	visited := make(map[string]bool, len(nodes))
+	inStack := make(map[string]bool, len(nodes))
+
+	var visit func(name string) error
+	visit = func(name string) error {
+		if inStack[name] {
+			return fmt.Errorf("cycle detected at job %q", name)
+		}
+		if visited[name] {
+			return nil
+		}
+		inStack[name] = true
+		for _, dep := range nodes[name].needs {
+			if err := visit(dep); err != nil {
+				return err
+			}
+		}
+		inStack[name] = false
+		visited[name] = true
+		order = append(order, name)
+		return nil
+	}
+
+	for name := range nodes {
+		if err := visit(name); err != nil {
+			return nil, err
+		}
+	}
+	return order, nil
+}
+
+// ReadyJobs returns the names of jobs whose dependencies are all in completedJobs.
+func ReadyJobs(jobs map[string]WorkflowJob, completedJobs map[string]bool, enqueuedJobs map[string]bool) []string {
+	var ready []string
+	for name, job := range jobs {
+		if enqueuedJobs[name] {
+			continue
+		}
+		allDone := true
+		for _, dep := range job.Needs {
+			if !completedJobs[dep] {
+				allDone = false
+				break
+			}
+		}
+		if allDone {
+			ready = append(ready, name)
+		}
+	}
+	return ready
+}