Changing default encoding of Python?

Starting with PyDev 3.4.1, the default encoding is not being changed anymore. See this ticket for details.

For earlier versions a solution is to make sure PyDev does not run with UTF-8 as the default encoding. Under Eclipse, run dialog settings ("run configurations", if I remember correctly); you can choose the default encoding on the common tab. Change it to US-ASCII if you want to have these errors 'early' (in other words: in your PyDev environment). Also see an original blog post for this workaround.

You could change the encoding of your entire operating system. On Ubuntu you can do this with

sudo apt install locales 
sudo locale-gen en_US en_US.UTF-8    
sudo dpkg-reconfigure locales

set default encoding of OS to be UTF-8. Eg., on ubuntu edit file /etc/default/locale and set:

LANG=en_US.UTF-8
LANGUAGE=en_US.UTF-8
LC_ALL=en_US.UTF-8

If you only want stable UTF-8 support on file read/write without same declarations everywhere, here are two solutions:

1. Patch io module at runtime (danger operation at your own risk)

import pathlib as pathlib
import tempfile

import chardet


def patchIOWithUtf8Default():
    import builtins
    import importlib.util
    import sys
    spec = importlib.util.find_spec("io")
    module = importlib.util.module_from_spec(spec)
    exec(compile(spec.loader.get_source(spec.name) + """
    def open(*args, **kwargs):
        args = list(args)
        mode = kwargs.get('mode', (args + [''])[1])
        if (len(args) < 4 and 'b' not in mode) or 'encoding' in kwargs:
            kwargs['encoding'] = 'utf8'
        elif len(args) >= 4 and args[3] is None:
            args[3] = 'utf8'
        return _io.open(*args, **kwargs)
    """, module.__spec__.origin, "exec"), module.__dict__)
    sys.modules[module.__name__] = module
    builtins.open = __import__("io").open
    importlib.reload(importlib.import_module("pathlib"))


def main():
    patchIOWithUtf8Default()
    filename = tempfile.mktemp()
    text = "Common\n常\nSense\n识\n天地玄黄"
    print("Original text:", repr(text))
    pathlib.Path(filename).write_text(text)
    encoding = chardet.detect(open(filename, mode="rb").read())["encoding"]
    print("Written encoding by pathlib:", encoding)
    print("Written text by pathlib:", repr(open(filename, newline="", encoding=encoding).read()))


if __name__ == '__main__':
    main()

Sample output:

Original text: 'Common\n常\nSense\n识\n天地玄黄'
Written encoding by pathlib: utf-8
Written text by pathlib: 'Common\r\n常\r\nSense\r\n识\r\n天地玄黄'

2. Use 3rd library as pathlib wrapper

https://github.com/baijifeilong/IceSpringPathLib

pip install IceSpringPathLib

import pathlib
import tempfile

import chardet

import IceSpringPathLib

tempfile.mktemp()
filename = tempfile.mktemp()
text = "Common\n常\nSense\n识\n天地玄黄"
print("Original text:", repr(text))

pathlib.Path(filename).write_text(text)
encoding = chardet.detect(open(filename, mode="rb").read())["encoding"]
print("\nWritten text by pathlib:", repr(open(filename, newline="", encoding=encoding).read()))
print("Written encoding by pathlib:", encoding)

IceSpringPathLib.Path(filename).write_text(text)
encoding = chardet.detect(open(filename, mode="rb").read())["encoding"]
print("\nWritten text by IceSpringPathLib:", repr(open(filename, newline="", encoding=encoding).read()))
print("Written encoding by IceSpringPathLib:", encoding)

Sample output:

Original text: 'Common\n常\nSense\n识\n天地玄黄'

Written text by pathlib: 'Common\r\n常\r\nSense\r\n识\r\n天地玄黄'
Written encoding by pathlib: GB2312

Written text by IceSpringPathLib: 'Common\n常\nSense\n识\n天地玄黄'
Written encoding by IceSpringPathLib: utf-8