diff options
| -rwxr-xr-x | Lib/tarfile.py | 7 | ||||
| -rw-r--r-- | Lib/test/test_tarfile.py | 12 | ||||
| -rw-r--r-- | Lib/test/testtar.tar.xz | bin | 0 -> 172 bytes | |||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2021-03-13-14-02-07.bpo-8978.CRxG-O.rst | 2 |
4 files changed, 19 insertions, 2 deletions
diff --git a/Lib/tarfile.py b/Lib/tarfile.py index 395c0f1d300..18d415adf54 100755 --- a/Lib/tarfile.py +++ b/Lib/tarfile.py @@ -1604,17 +1604,20 @@ class TarFile(object): # Find out which *open() is appropriate for opening the file. def not_compressed(comptype): return cls.OPEN_METH[comptype] == 'taropen' + error_msgs = [] for comptype in sorted(cls.OPEN_METH, key=not_compressed): func = getattr(cls, cls.OPEN_METH[comptype]) if fileobj is not None: saved_pos = fileobj.tell() try: return func(name, "r", fileobj, **kwargs) - except (ReadError, CompressionError): + except (ReadError, CompressionError) as e: + error_msgs.append(f'- method {comptype}: {e!r}') if fileobj is not None: fileobj.seek(saved_pos) continue - raise ReadError("file could not be opened successfully") + error_msgs_summary = '\n'.join(error_msgs) + raise ReadError(f"file could not be opened successfully:\n{error_msgs_summary}") elif ":" in mode: filemode, comptype = mode.split(":", 1) diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py index 77ad8305c31..817e6f17997 100644 --- a/Lib/test/test_tarfile.py +++ b/Lib/test/test_tarfile.py @@ -2283,6 +2283,18 @@ class MiscTest(unittest.TestCase): 'SubsequentHeaderError', 'ExFileObject', 'main'} support.check__all__(self, tarfile, not_exported=not_exported) + def test_useful_error_message_when_modules_missing(self): + fname = os.path.join(os.path.dirname(__file__), 'testtar.tar.xz') + with self.assertRaises(tarfile.ReadError) as excinfo: + error = tarfile.CompressionError('lzma module is not available'), + with unittest.mock.patch.object(tarfile.TarFile, 'xzopen', side_effect=error): + tarfile.open(fname) + + self.assertIn( + "\n- method xz: CompressionError('lzma module is not available')\n", + str(excinfo.exception), + ) + class CommandLineTest(unittest.TestCase): diff --git a/Lib/test/testtar.tar.xz b/Lib/test/testtar.tar.xz Binary files differnew file mode 100644 index 00000000000..512fa149e6c --- /dev/null +++ b/Lib/test/testtar.tar.xz diff --git a/Misc/NEWS.d/next/Library/2021-03-13-14-02-07.bpo-8978.CRxG-O.rst b/Misc/NEWS.d/next/Library/2021-03-13-14-02-07.bpo-8978.CRxG-O.rst new file mode 100644 index 00000000000..2da8874dc7f --- /dev/null +++ b/Misc/NEWS.d/next/Library/2021-03-13-14-02-07.bpo-8978.CRxG-O.rst @@ -0,0 +1,2 @@ +Improve error message for :func:`tarfile.open` when :mod:`lzma` / :mod:`bz2` +are unavailable. Patch by Anthony Sottile. |