Feature or enhancement

Regular file objects returned by the open() building have name and name and mode attributes. Some code may use these optional attributes for different purposes, for example to distinguish readable files from writable files, binary files from text files, or just for formatting the repr or error messages. For example:

• cpython/Lib/tarfile.py

  Line 1666 in 5a83292

  if (name is None and hasattr(fileobj, "name") and

• cpython/Lib/tarfile.py

  Line 1669 in 5a83292

  if hasattr(fileobj, "mode"):

• cpython/Lib/socket.py

  Line 455 in 5a83292

  if 'b' not in getattr(file, 'mode', 'b'):

• cpython/Lib/gzip.py

  Line 201 in 5a83292

  mode = getattr(fileobj, 'mode', 'rb')

• cpython/Lib/asyncio/base_events.py

  Line 982 in 5a83292

  if 'b' not in getattr(file, 'mode', 'b'):

• cpython/Lib/wave.py

  Line 654 in 5a83292

  if hasattr(f, 'mode'):

There are several file-like objects in compressing modules gzip, bz2 and lama and archiving modules zipfile and tarfile. They usually implement the raw or buffered file protocols from io, but not always have name and mode attributes, and when they have, they not always have common semantic.

GzipFile, unlike to BZ2File and LZMAFile, has name and mode attributes, but mode is an integer, that confuses tarfile (see #62775).

ZipExtFile has the mode attribute which is always 'r'. It is a legacy from Python 2, when it could also be 'U' or 'rU' for files with universal newlines. But this mode was removed long time ago, and since it is a binary file, its mode should be 'rb'.

See also #68446, #91373, #91374. I opened this issue because consider it all the parts of larger image.

Linked PRs

• gh-115961: Improve tests for compressed file-like objects #115963
• [3.12] gh-115961: Improve tests for compressed file-like objects (GH-115963) #116032
• gh-115961: Add name and mode attributes for compressed file-like objects #116036
• [3.11] gh-115961: Improve tests for compressed file-like objects (GH-115963) #116039