dir2config: switch to includes instead of ad-hoc defaults

cmd/dkl-dir2config/git.go

@@ -0,0 +1,38 @@
+package main
+
+import (
+	"io"
+	"sort"
+
+	"github.com/go-git/go-git/v5/plumbing/object"
+)
+
+type gitFS struct{ *object.Tree }
+
+func (fs gitFS) Open(path string) (r io.ReadCloser, err error) {
+	f, err := fs.Tree.File(path)
+	if err != nil {
+		return
+	}
+	return f.Reader()
+}
+
+func (fs gitFS) List(path string) (entries []string, err error) {
+	tree, err := fs.Tree.Tree(path)
+	if err != nil {
+		return
+	}
+
+	entries = make([]string, 0, len(tree.Entries))
+
+	for _, ent := range tree.Entries {
+		if !ent.Mode.IsFile() {
+			continue
+		}
+
+		entries = append(entries, ent.Name)
+	}
+
+	sort.Strings(entries)
+	return
+}