Only run task once for #53

hash.go

@@ -0,0 +1,28 @@
+package task
+
+import (
+	"fmt"
+
+	"github.com/go-task/task/v3/internal/hash"
+	"github.com/go-task/task/v3/taskfile"
+)
+
+func (e *Executor) GetHash(t *taskfile.Task) (string, error) {
+	r := t.Run
+	if r == "" {
+		r = e.Taskfile.Run
+	}
+
+	var h hash.HashFunc
+	switch r {
+	case "always":
+		h = hash.Empty
+	case "once":
+		h = hash.Name
+	case "when_changed":
+		h = hash.Hash
+	default:
+		return "", fmt.Errorf(`task: invalid run "%s"`, r)
+	}
+	return h(t)
+}