Possible UnicodeError caused by missing encoding="utf-8"

[methane]

tox/src/tox/config/__init__.py

Lines 304 to 306 in 555f3f1

	def get_py_project_toml(path):
	with open(str(path)) as file_handler:
	config_data = toml.load(file_handler)

toml must be encoded by UTF-8. Please add encoding="utf-8" here.
It may cause UnicodeDecodeError when pyproject.toml contains non-ASCII character and locale encoding is not UTF-8 (e.g. Windows).

tox/src/tox/util/stdlib.py

Lines 52 to 55 in 555f3f1

	with TemporaryFile("wt") as file:
	with redirect_stdout(file):
	with redirect_stderr(file):
	yield

On Windows, stdout is UTF-8 encoded when it is console (e.g. _WinConsoleIO), but the default encoding of TemporaryFile() is legacy encoding. So UTF-8 is better encoding for this purpose.

This is not a real bug because this function is used only here:

tox/src/tox/session/__init__.py

Line 54 in cfe38bb

with suppress_output():

[domdfcoding]

I have encountered this issue "in the wild" with a pyproject.toml file containing UTF-8 characters.

The traceback is:

Traceback (most recent call last):
  File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\tox\__main__.py", line 4, in <module>
    tox.cmdline()
  File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\tox\session\__init__.py", line 44, in cmdline
    main(args)
  File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\tox\session\__init__.py", line 65, in main
    config = load_config(args)
  File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\tox\session\__init__.py", line 81, in load_config
    config = parseconfig(args)
  File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\tox\config\__init__.py", line 274, in parseconfig
    toml_content = get_py_project_toml(config_file)
  File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\tox\config\__init__.py", line 306, in get_py_project_toml
    config_data = toml.load(file_handler)
  File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\site-packages\toml\decoder.py", line 156, in load
    return loads(f.read(), _dict, decoder)
  File "C:\hostedtoolcache\windows\Python\3.6.8\x64\lib\encodings\cp1252.py", line 23, in decode
    return codecs.charmap_decode(input,self.errors,decoding_table)[0]
UnicodeDecodeError: 'charmap' codec can't decode byte 0x90 in position 219: character maps to <undefined>