feat: XDG taskrc config (#2380)

Co-authored-by: Valentin Maerten <maerten.valentin@gmail.com>

taskrc/taskrc.go

@@ -1,6 +1,63 @@
 package taskrc
 
+import (
+	"os"
+	"path/filepath"
+	"slices"
+
+	"github.com/go-task/task/v3/internal/fsext"
+	"github.com/go-task/task/v3/taskrc/ast"
+)
+
 var defaultTaskRCs = []string{
 	".taskrc.yml",
 	".taskrc.yaml",
 }
+
+// GetConfig loads and merges local and global Task configuration files
+func GetConfig(dir string) (*ast.TaskRC, error) {
+	var config *ast.TaskRC
+	reader := NewReader()
+
+	// Read the XDG config file
+	if xdgConfigHome := os.Getenv("XDG_CONFIG_HOME"); xdgConfigHome != "" {
+		xdgConfigNode, err := NewNode("", filepath.Join(xdgConfigHome, "task"))
+		if err == nil && xdgConfigNode != nil {
+			config, err = reader.Read(xdgConfigNode)
+			if err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	// Find all the nodes from the given directory up to the users home directory
+	entrypoints, err := fsext.SearchAll("", dir, defaultTaskRCs)
+	if err != nil {
+		return nil, err
+	}
+
+	// Reverse the entrypoints since we want the child files to override parent ones
+	slices.Reverse(entrypoints)
+
+	// Loop over the nodes, and merge them into the main config
+	for _, entrypoint := range entrypoints {
+		node, err := NewNode("", entrypoint)
+		if err != nil {
+			return nil, err
+		}
+		localConfig, err := reader.Read(node)
+		if err != nil {
+			return nil, err
+		}
+		if localConfig == nil {
+			continue
+		}
+		if config == nil {
+			config = localConfig
+			continue
+		}
+		config.Merge(localConfig)
+	}
+
+	return config, nil
+}