RepoTree: preserve relative paths in copytree() (#4133)

dvc/repo/tree.py

@@ -428,11 +428,12 @@ class RepoTree(BaseTree):
 
         for root, _, files in self.walk(top):
             root = PathInfo(root)
-            makedirs(dest, exist_ok=True)
+            dest_dir = dest / root.relative_to(top)
+            makedirs(dest_dir, exist_ok=True)
             for fname in files:
                 src = root / fname
                 with self.open(src, mode="rb") as fobj:
-                    copy_fobj_to_file(fobj, dest / fname)
+                    copy_fobj_to_file(fobj, dest_dir / fname)
 
     @property
     def hash_jobs(self):

tests/func/test_get.py

@@ -55,7 +55,9 @@ def test_get_git_dir(tmp_dir, erepo):
     src = "some_directory"
     dst = "some_directory_imported"
 
-    erepo.scm_gen({src: {"file.txt": "hello"}}, commit="add a regular dir")
+    erepo.scm_gen(
+        {src: {"dir": {"file.txt": "hello"}}}, commit="add a regular dir"
+    )
 
     Repo.get(os.fspath(erepo), src, dst)