feat: merger

taskfile/ast/graph.go

@@ -1,10 +1,14 @@
 package ast
 
 import (
+	"fmt"
 	"os"
 
 	"github.com/dominikbraun/graph"
 	"github.com/dominikbraun/graph/draw"
+	"golang.org/x/sync/errgroup"
+
+	"github.com/go-task/task/v3/internal/filepathext"
 )
 
 type TaskfileGraph struct {
@@ -31,11 +35,118 @@ func NewTaskfileGraph() *TaskfileGraph {
 	}
 }
 
-func (r *TaskfileGraph) Visualize(filename string) error {
+func (tfg *TaskfileGraph) Visualize(filename string) error {
 	f, err := os.Create(filename)
 	if err != nil {
 		return err
 	}
 	defer f.Close()
-	return draw.DOT(r.Graph, f)
+	return draw.DOT(tfg.Graph, f)
+}
+
+func (tfg *TaskfileGraph) Merge() (*Taskfile, error) {
+	hashes, err := graph.TopologicalSort(tfg.Graph)
+	if err != nil {
+		return nil, err
+	}
+
+	predecessorMap, err := tfg.PredecessorMap()
+	if err != nil {
+		return nil, err
+	}
+
+	for i := len(hashes) - 1; i >= 0; i-- {
+		hash := hashes[i]
+
+		// Get the current vertex
+		vertex, err := tfg.Vertex(hash)
+		if err != nil {
+			return nil, err
+		}
+
+		// Create an error group to wait for all the included Taskfiles to be merged with all its parents
+		var g errgroup.Group
+
+		// Loop over each adjacent edge
+		for _, edge := range predecessorMap[hash] {
+
+			// TODO: Enable goroutines
+			// Start a goroutine to process each included Taskfile
+			// g.Go(
+			err := func() error {
+				// Get the child vertex
+				predecessorVertex, err := tfg.Vertex(edge.Source)
+				if err != nil {
+					return err
+				}
+
+				// Get the merge options
+				include, ok := edge.Properties.Data.(*Include)
+				if !ok {
+					return fmt.Errorf("task: Failed to get merge options")
+				}
+
+				// Handle advanced imports
+				// i.e. where additional data is given when a Taskfile is included
+				if include.AdvancedImport {
+					predecessorVertex.Taskfile.Vars.Range(func(k string, v Var) error {
+						o := v
+						o.Dir = include.Dir
+						predecessorVertex.Taskfile.Vars.Set(k, o)
+						return nil
+					})
+					predecessorVertex.Taskfile.Env.Range(func(k string, v Var) error {
+						o := v
+						o.Dir = include.Dir
+						predecessorVertex.Taskfile.Env.Set(k, o)
+						return nil
+					})
+					for _, task := range vertex.Taskfile.Tasks.Values() {
+						task.Dir = filepathext.SmartJoin(include.Dir, task.Dir)
+						if task.IncludeVars == nil {
+							task.IncludeVars = &Vars{}
+						}
+						task.IncludeVars.Merge(include.Vars)
+						task.IncludedTaskfileVars = vertex.Taskfile.Vars
+					}
+				}
+
+				// Merge the included Taskfile into the parent Taskfile
+				if err := predecessorVertex.Taskfile.Merge(
+					vertex.Taskfile,
+					include,
+				); err != nil {
+					return err
+				}
+
+				return nil
+			}()
+			if err != nil {
+				return nil, err
+			}
+			// )
+		}
+
+		// Wait for all the go routines to finish
+		if err := g.Wait(); err != nil {
+			return nil, err
+		}
+	}
+
+	// Get the root vertex
+	rootVertex, err := tfg.Vertex(hashes[0])
+	if err != nil {
+		return nil, err
+	}
+
+	rootVertex.Taskfile.Tasks.Range(func(name string, task *Task) error {
+		if task == nil {
+			task = &Task{}
+			rootVertex.Taskfile.Tasks.Set(name, task)
+		}
+		task.Task = name
+		return nil
+	})
+
+	return rootVertex.Taskfile, nil
 }