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Deprecate codecs.open() #133036
Description
Discussion: https://discuss.python.org/t/deprecating-codecs-open/88135/
codecs.open() is used a lot because it was recommended in Python 2.
But open() (or io.open()) is recommended since Python 3.
It is a time to deprecate codecs.open().
Since it is still widely used, we won't schedule its removal.
Activity
pythongh-133036: deprecate codecs.open
gh-133036: Deprecate codecs.open (#133038)
ngoldbaum commented on Aug 7, 2025
I don't know if this deserves a better clarification in the deprecation notice, but I hit a corner case that took me a few minutes to understand today. Perhaps commenting here will help someone else.
I tried replacing codecs.open with open in a spot in pandas and hit this error:
> with open(as_json, "wb", encoding="utf8") as f: ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ E ValueError: binary mode doesn't take an encoding argumentI fixed it by replacing "wb" with "w". It seems codecs.open is a little more permissive here than open.