api: fix get_url() when CWD is a subdirectory of the repo

dvc/repo/__init__.py

@@ -387,15 +387,24 @@ def get_data_index_entry(
         path: str,
         workspace: str = "repo",
     ) -> tuple["DataIndex", "DataIndexEntry"]:
+        abspath = path
+        if not os.path.isabs(abspath):
+            # `path` is interpreted as relative to the root of the repo, not
+            # the current working directory (which may be a subdirectory of
+            # the repo). See #11029.
+            abspath = self.fs.join(self.root_dir, abspath)
         if self.subrepos:
-            fs_path = self.dvcfs.from_os_path(path)
+            # `from_os_path` returns a path relative to the repo root. Anchor
+            # it at the filesystem root so it is not re-resolved against the
+            # filesystem's current working directory.
+            fs_path = self.dvcfs.from_os_path(abspath)
             fs = self.dvcfs.fs
-            key = fs._get_key_from_relative(fs_path)
+            key = fs._get_key_from_relative(fs.root_marker + fs_path)
             subrepo, _, key = fs._get_subrepo_info(key)
             index = subrepo.index.data[workspace]
         else:
             index = self.index.data[workspace]
-            key = self.fs.relparts(path, self.root_dir)
+            key = self.fs.relparts(abspath, self.root_dir)
 
         try:
             return index, index[key]

tests/func/api/test_data.py

@@ -250,6 +250,22 @@ def test_get_url_granular(tmp_dir, dvc, cloud):
     assert api.get_url(os.path.join("dir", "nested", "file")) == expected_url
 
 
+def test_get_url_from_subdir(tmp_dir, dvc, local_cloud):
+    tmp_dir.add_remote(config=local_cloud.config)
+    tmp_dir.dvc_gen({"foo": "foo", "subdir": {"bar": "bar"}})
+
+    expected_url = (
+        local_cloud / "files" / "md5" / "ac" / "bd18db4cc2f85cedef654fccc4a4d8"
+    ).url
+
+    # A relative path is relative to the root of the repo, even when the
+    # current working directory is a subdirectory of the repo (#11029).
+    subdir = tmp_dir / "subdir"
+    with subdir.chdir():
+        assert api.get_url("foo") == expected_url
+        assert api.get_url("foo", repo=os.fspath(tmp_dir)) == expected_url
+
+
 def test_get_url_subrepos(tmp_dir, scm, local_cloud):
     subrepo = tmp_dir / "subrepo"
     make_subrepo(subrepo, scm, config=local_cloud.config)