Hi, all.
I am rewriting PEP 597 to introduce a new EncodingWarning, which subclass of DeprecationWarning and used to warn about future default encoding change. But I don't think we can change the default encoding of `io.TextIOWrapper` and built-in `open()` anytime soon. It is disruptive change. It may take 10 or more years.
To ease the pain caused by "default encoding is not UTF-8 (almost) only on Windows" (*), I came up with another idea. This idea is not mutually exclusive with PEP 597, but I want to include it in the PEP because both ideas use EncodingWarning.
(*) Imagine that a new Python user writes a text file with notepad.exe (default encoding is UTF-8 without BOM already) or VS Code, and try to read it in Jupyter Notebook. They will see UnicodeDecodeError. They might not know about what encoding yet.
## 1. Add `io.open_text()`, builtin `open_text()`, and `pathlib.Path.open_text()`.
All functions are same to `io.open()` or `Path.open()`, except:
* Default encoding is "utf-8". * "b" is not allowed in the mode option.
These functions have two benefits:
* `open_text(filename)` is shorter than `open(filename, encoding="utf-8")`. Its easy to type especially with autocompletion. * Type annotation for returned value is simple than `open`. It is always TextIOWrapper.
## 2. Change the default encoding of `pathlib.Path.read_text()`.
For convenience and consistency with `Path.open_text()`, change the default encoding of `Path.read_text()` to "utf-8" with regular deprecation period.
* Python 3.10: `Path.read_text()` emits EncodingWarning when the encoding option is omitted. * Python 3.13: `Path.read_text()` change the default encoding to "utf-8".
If PEP 597 is accepted, users can pass `encoding="locale"` instead of `encoding=locale.getpreferredencoding(False)` when they need to use locale encoding.
We might change more places where the default encoding is used. But it should be done slowly and carefully.
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How do you think about this idea? Is this worth enough to add a new built-in function?
Regards,