Fix imagefolder with one image (#6556)

* fix imagefolder with one image

* better typing

* fix flaky test

Author: lhoestq

src/datasets/load.py

@@ -491,7 +491,7 @@ def _load_importable_file(
 
 def infer_module_for_data_files_list(
     data_files_list: DataFilesList, download_config: Optional[DownloadConfig] = None
-) -> Optional[Tuple[str, str]]:
+) -> Tuple[Optional[str], dict]:
     """Infer module (and builder kwargs) from list of data files.
 
     It picks the module based on the most common file extension.
@@ -507,18 +507,18 @@ def infer_module_for_data_files_list(
             - dict of builder kwargs
     """
     extensions_counter = Counter(
-        "." + suffix.lower()
+        ("." + suffix.lower(), xbasename(filepath) in ("metadata.jsonl", "metadata.csv"))
         for filepath in data_files_list[: config.DATA_FILES_MAX_NUMBER_FOR_MODULE_INFERENCE]
         for suffix in xbasename(filepath).split(".")[1:]
     )
     if extensions_counter:
 
-        def sort_key(ext_count: Tuple[str, int]) -> Tuple[int, bool]:
-            """Sort by count and set ".parquet" as the favorite in case of a draw"""
-            ext, count = ext_count
-            return (count, ext == ".parquet", ext)
+        def sort_key(ext_count: Tuple[Tuple[str, bool], int]) -> Tuple[int, bool]:
+            """Sort by count and set ".parquet" as the favorite in case of a draw, and ignore metadata files"""
+            (ext, is_metadata), count = ext_count
+            return (not is_metadata, count, ext == ".parquet", ext)
 
-        for ext, _ in sorted(extensions_counter.items(), key=sort_key, reverse=True):
+        for (ext, _), _ in sorted(extensions_counter.items(), key=sort_key, reverse=True):
             if ext in _EXTENSION_TO_MODULE:
                 return _EXTENSION_TO_MODULE[ext]
             elif ext == ".zip":
@@ -528,7 +528,7 @@ def sort_key(ext_count: Tuple[str, int]) -> Tuple[int, bool]:
 
 def infer_module_for_data_files_list_in_archives(
     data_files_list: DataFilesList, download_config: Optional[DownloadConfig] = None
-) -> Optional[Tuple[str, str]]:
+) -> Tuple[Optional[str], dict]:
     """Infer module (and builder kwargs) from list of archive data files.
 
     Args:

src/datasets/packaged_modules/__init__.py

@@ -1,6 +1,6 @@
 import inspect
 import re
-from typing import Dict, List
+from typing import Dict, List, Tuple
 
 from huggingface_hub.utils import insecure_hashlib
 
@@ -44,7 +44,7 @@ def _hash_python_lines(lines: List[str]) -> str:
 }
 
 # Used to infer the module to use based on the data files extensions
-_EXTENSION_TO_MODULE = {
+_EXTENSION_TO_MODULE: Dict[str, Tuple[str, dict]] = {
     ".csv": ("csv", {}),
     ".tsv": ("csv", {"sep": "\t"}),
     ".json": ("json", {}),

tests/test_arrow_dataset.py

@@ -3995,8 +3995,8 @@ def test_build_local_temp_path(uri_or_path):
     path_relative_to_tmp_dir = Path(local_temp_path).relative_to(Path(tempfile.gettempdir())).as_posix()
 
     assert (
-        "hdfs" not in path_relative_to_tmp_dir
-        and "s3" not in path_relative_to_tmp_dir
+        "hdfs://" not in path_relative_to_tmp_dir
+        and "s3://" not in path_relative_to_tmp_dir
         and not local_temp_path.startswith(extracted_path_without_anchor)
         and local_temp_path.endswith(extracted_path_without_anchor)
     ), f"Local temp path: {local_temp_path}"