Make tree.walk() output deterministic

dvc/utils/__init__.py

@@ -296,6 +296,11 @@ def dvc_walk(top, dvcignore, topdown=True, onerror=None, followlinks=False):
     for root, dirs, files in os.walk(
         top, topdown=topdown, onerror=onerror, followlinks=followlinks
     ):
+        # Dirs are returned in arbitrary order on different platforms. Force a
+        # specific order so that we can make deterministic assumptions on the
+        # directory order.
+        # https://stackoverflow.com/a/54773660/2966951
+        dirs.sort()
 
         if dvcignore:
             dirs[:], files[:] = dvcignore(root, dirs, files)

tests/func/test_tree.py

@@ -118,13 +118,13 @@ class TestWalkInNoSCM(AssertWalkEqualMixin, TestDir):
                     ["lib", "data_dir"],
                     ["code.py", "bar", "тест", "foo"],
                 ),
-                (join(self._root_dir, "lib"), [], ["file.txt"]),
                 (join(self._root_dir, "data_dir"), ["data_sub_dir"], ["data"]),
                 (
                     join(self._root_dir, "data_dir", "data_sub_dir"),
                     [],
                     ["data_sub"],
                 ),
+                (join(self._root_dir, "lib"), [], ["file.txt"]),
             ],
         )
 
@@ -155,13 +155,13 @@ class TestWalkInGit(AssertWalkEqualMixin, TestGit):
                     ["lib", "data_dir"],
                     ["bar", "тест", "code.py", "foo"],
                 ),
-                (join(self._root_dir, "lib"), [], ["file.txt"]),
                 (join(self._root_dir, "data_dir"), ["data_sub_dir"], ["data"]),
                 (
                     join(self._root_dir, "data_dir", "data_sub_dir"),
                     [],
                     ["data_sub"],
                 ),
+                (join(self._root_dir, "lib"), [], ["file.txt"]),
             ],
         )
         self.assertWalkEqual(