From c1306bb5b8ff4e5db1da360f98db869f3656487e Mon Sep 17 00:00:00 2001
From: Nicholas Devenish <ndevenish@gmail.com>
Date: Wed, 5 Nov 2025 11:02:05 +0000
Subject: [PATCH] Make the pathlib ValueError a warning

---
 dials_data/download.py | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/dials_data/download.py b/dials_data/download.py
index 9b205a23..3deac95b 100644
--- a/dials_data/download.py
+++ b/dials_data/download.py
@@ -7,6 +7,7 @@
 import hashlib
 import os
 import tarfile
+import warnings
 import zipfile
 from pathlib import Path
 from typing import Any
@@ -309,9 +310,10 @@ def __call__(self, test_data: str, **kwargs):
                  if the dataset is not available.
         """
         if "pathlib" in kwargs:
-            raise ValueError(
-                "The pathlib parameter has been removed. The "
-                "DataFetcher always returns pathlib.Path() objects now."
+            warnings.warn(
+                "pathlib argument is deprecated: Using Pathlib is now the default (and only) option.",
+                UserWarning,
+                stacklevel=2,
             )
         if test_data not in self._cache:
             self._cache[test_data] = self._attempt_fetch(test_data)