From da927ad5fe9b1d910d59b1df79b62cc4e7c5996d Mon Sep 17 00:00:00 2001
From: Valentin Maerten <maerten.valentin@gmail.com>
Date: Fri, 26 Dec 2025 21:00:02 +0100
Subject: [PATCH] feat(graph): add Root() helper method

Add Root() method to TaskfileGraph to get the root vertex (entrypoint
Taskfile). This will be used for lazy variable resolution.

Note: Tasks already have Location.Taskfile which can be used to find
their source Taskfile in the graph, so GetVertexByNamespace is not
needed.
---
 taskfile/ast/graph.go | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/taskfile/ast/graph.go b/taskfile/ast/graph.go
index cb30093d..b6c27438 100644
--- a/taskfile/ast/graph.go
+++ b/taskfile/ast/graph.go
@@ -45,6 +45,18 @@ func (tfg *TaskfileGraph) Visualize(filename string) error {
 	return draw.DOT(tfg.Graph, f)
 }
 
+// Root returns the root vertex of the graph (the entrypoint Taskfile).
+func (tfg *TaskfileGraph) Root() (*TaskfileVertex, error) {
+	hashes, err := graph.TopologicalSort(tfg.Graph)
+	if err != nil {
+		return nil, err
+	}
+	if len(hashes) == 0 {
+		return nil, fmt.Errorf("task: graph has no vertices")
+	}
+	return tfg.Vertex(hashes[0])
+}
+
 func (tfg *TaskfileGraph) Merge() (*Taskfile, error) {
 	hashes, err := graph.TopologicalSort(tfg.Graph)
 	if err != nil {