tarball: Try to get archive format before unpacking it

By default shutil.unpack_archive will try to match the archive format
from its extension but it does not do it in a case insensitive way.
Thus trying to extract a file named "archive.ZIP" will fail.

So try to detect archive format in a case insensitive way by processing
the data returned by shutil.get_unpack_formats prior unpacking.

swh/core/tarball.py

@@ -90,11 +90,16 @@ def uncompress(tarpath: str, dest: str):
     """
     try:
         os.makedirs(dest, exist_ok=True)
-        shutil.unpack_archive(tarpath, extract_dir=dest)
+        format = None
+        for format_, exts, _ in shutil.get_unpack_formats():
+            if any([tarpath.lower().endswith(ext.lower()) for ext in exts]):
+                format = format_
+                break
+        shutil.unpack_archive(tarpath, extract_dir=dest, format=format)
     except shutil.ReadError as e:
         raise ValueError(f"Problem during unpacking {tarpath}. Reason: {e}")
     except NotImplementedError:
-        if tarpath.endswith(".zip"):
+        if tarpath.lower().endswith(".zip"):
             _unpack_zip(tarpath, dest)
         else:
             raise

swh/core/tests/test_tarball.py

@@ -222,3 +222,21 @@ def test_unpcompress_zip_imploded(tmp_path, datadir):
     tarball.uncompress(zippath, extract_dir)
 
     assert len(os.listdir(extract_dir)) > 0
+
+
+def test_uncompress_upper_archive_extension(tmp_path, datadir):
+    """Copy test archives in a temporary directory but turn their names
+    to uppercase, then check they can be successfully extracted.
+    """
+    archives_path = os.path.join(datadir, "archives")
+    archive_files = [
+        f
+        for f in os.listdir(archives_path)
+        if os.path.isfile(os.path.join(archives_path, f))
+    ]
+    for archive_file in archive_files:
+        archive_file_upper = os.path.join(tmp_path, archive_file.upper())
+        extract_dir = os.path.join(tmp_path, archive_file)
+        shutil.copy(os.path.join(archives_path, archive_file), archive_file_upper)
+        tarball.uncompress(archive_file_upper, extract_dir)
+        assert len(os.listdir(extract_dir)) > 0