When running with a file that had only root access permissions, running diffoscope as a regular user fails. This was seen in a live image for the file `/etc/.pwd.lock` Minimal case to reproduce the issue: As root: * `touch a b` * `chmod go= a b` As a regular user * `diffoscope a b` <details><summary>The result</summary> ``` Traceback (most recent call last): File "/usr/bin/diffoscope", line 36, in <module> main() File "/usr/lib/python3/dist-packages/diffoscope/main.py", line 767, in main sys.exit(run_diffoscope(parsed_args)) ^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3/dist-packages/diffoscope/main.py", line 718, in run_diffoscope difference = compare_root_paths(path1, path2) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3/dist-packages/diffoscope/comparators/utils/compare.py", line 66, in compare_root_paths file1 = specialize(FilesystemFile(path1, container=container1)) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3/dist-packages/diffoscope/comparators/utils/specialize.py", line 75, in specialize if try_recognize(file, cls, cls.recognizes): ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3/dist-packages/diffoscope/comparators/utils/specialize.py", line 35, in try_recognize if not recognizes(file): ^^^^^^^^^^^^^^^^ File "/usr/lib/python3/dist-packages/diffoscope/comparators/debian.py", line 253, in recognizes if not super().recognizes(file): ^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3/dist-packages/diffoscope/comparators/utils/file.py", line 176, in recognizes file.magic_file_type, ^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3/dist-packages/diffoscope/comparators/utils/file.py", line 325, in magic_file_type self._magic_file_type = File.guess_file_type(self.path) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3/dist-packages/diffoscope/comparators/utils/file.py", line 108, in guess_file_type return maybe_decode(cls._mimedb.from_file(path)) ^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/usr/lib/python3/dist-packages/magic/__init__.py", line 112, in from_file with _real_open(filename): ^^^^^^^^^^^^^^^^^^^^ PermissionError: [Errno 13] Permission denied: 'a' ``` </details>