feat: node refactor (#1316)

* refactor: node reader interface

* refactor: rewrite Taskfile() as anon recursive func

* chore: NewNodeFromIncludedTaskfile

* chore: changelog

taskfile/read/node_file.go

@@ -0,0 +1,70 @@
+package read
+
+import (
+	"os"
+	"path/filepath"
+
+	"gopkg.in/yaml.v3"
+
+	"github.com/go-task/task/v3/errors"
+	"github.com/go-task/task/v3/internal/filepathext"
+	"github.com/go-task/task/v3/taskfile"
+)
+
+// A FileNode is a node that reads a taskfile from the local filesystem.
+type FileNode struct {
+	BaseNode
+	Dir        string
+	Entrypoint string
+}
+
+func NewFileNode(parent Node, path string, optional bool) (*FileNode, error) {
+	path, err := exists(path)
+	if err != nil {
+		return nil, err
+	}
+
+	return &FileNode{
+		BaseNode: BaseNode{
+			parent:   parent,
+			optional: optional,
+		},
+		Dir:        filepath.Dir(path),
+		Entrypoint: filepath.Base(path),
+	}, nil
+}
+
+func (node *FileNode) Location() string {
+	return filepathext.SmartJoin(node.Dir, node.Entrypoint)
+}
+
+func (node *FileNode) Read() (*taskfile.Taskfile, error) {
+	if node.Dir == "" {
+		d, err := os.Getwd()
+		if err != nil {
+			return nil, err
+		}
+		node.Dir = d
+	}
+
+	path, err := existsWalk(node.Location())
+	if err != nil {
+		return nil, err
+	}
+	node.Dir = filepath.Dir(path)
+	node.Entrypoint = filepath.Base(path)
+
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	var t taskfile.Taskfile
+	if err := yaml.NewDecoder(f).Decode(&t); err != nil {
+		return nil, &errors.TaskfileInvalidError{URI: filepathext.TryAbsToRel(path), Err: err}
+	}
+
+	t.Location = path
+	return &t, nil
+}