director: hold huggingface_hub below 2 (httpx renamed)

kaggle/notebook_director.py

@@ -15,13 +15,19 @@ def sh(cmd: str) -> None:
 
 
 def main() -> None:
-    # One resolver pass: transformers 5 expects a newer huggingface_hub than the
-    # image ships, and installing them separately leaves `httpx` missing from
-    # huggingface_hub.utils.
-    sh("pip install -q --upgrade 'transformers>=5' 'huggingface_hub>=1.0' accelerate")
-
-    import transformers
-    print("transformers", transformers.__version__, flush=True)
+    # transformers 5 imports `httpx` from huggingface_hub.utils. huggingface_hub
+    # 2.x renamed that to httpx2 and the import fails, so hold hub below 2.
+    sh("pip install -q --upgrade 'transformers>=5' 'huggingface_hub>=1.31,<2' accelerate")
+
+    check = subprocess.run(
+        [sys.executable, "-c",
+         "import transformers, huggingface_hub as h;"
+         "print('transformers', transformers.__version__, 'hub', h.__version__);"
+         "from huggingface_hub.utils import httpx; print('httpx ok')"],
+        capture_output=True, text=True)
+    print(check.stdout.strip() or check.stderr[-600:], flush=True)
+    if check.returncode != 0:
+        raise SystemExit("director environment is broken")
 
     from huggingface_hub import snapshot_download