external_repo: fix bug in path resolution (#3350)

dvc/external_repo.py

@@ -84,7 +84,7 @@ class ExternalRepo(Repo):
 
         try:
             if out and out.use_cache:
-                self._pull_cached(out, path, to_info)
+                self._pull_cached(out, path_info, to_info)
                 return
 
             # Check if it is handled by Git (it can't have an absolute path)
@@ -95,11 +95,10 @@ class ExternalRepo(Repo):
         except FileNotFoundError:
             raise PathMissingError(path, self.url)
 
-    def _pull_cached(self, out, src, dest):
+    def _pull_cached(self, out, path_info, dest):
         with self.state:
             tmp = PathInfo(tmp_fname(dest))
-            target = (out.path_info.parent / src).relative_to(out.path_info)
-            src = tmp / target
+            src = tmp / path_info.relative_to(out.path_info)
 
             out.path_info = tmp
 

tests/func/test_external_repo.py

@@ -1,3 +1,5 @@
+import os
+
 from mock import patch
 from dvc.compat import fspath
 
@@ -71,3 +73,18 @@ def test_known_sha(erepo_dir):
     # No clone, no pull, copies a repo, checks out the known sha
     with external_repo(url, prev_rev) as repo:
         pass
+
+
+def test_pull_subdir_file(tmp_dir, erepo_dir):
+    with erepo_dir.chdir():
+        subdir = erepo_dir / "subdir"
+        subdir.mkdir()
+        (subdir / "file").write_text("contents")
+        erepo_dir.dvc_add(subdir / "file", commit="create file")
+
+    dest = tmp_dir / "file"
+    with external_repo(fspath(erepo_dir)) as repo:
+        repo.pull_to(os.path.join("subdir", "file"), dest)
+
+    assert dest.is_file()
+    assert dest.read_text() == "contents"