07.04.21 19:13, Victor Stinner пише:
I'm +0 on removing again the flag, but I would prefer to not endorse the responsibility. I am already responsible for enough incompatible changes in Python 3.10 :-D
Some context on this "U" open mode. The flag is accepted by many functions opening files. It is deprecated (emit DeprecationWarning) for 9 years (Python 3.3, 2012).
It was silently deprecated before 3.3 (perhaps it was no-op since 3.0).
I added DeprecationWarning with intention to remove this option in all functions accepting it. The only non-trivial support of the "U" mode was left in ZipFile.open(), and it was broken since beginning.