locale.nl_langinfo() can't decode THOUSEP monetary value

[serhiy-storchaka]

BPO	25812
Nosy	@malemburg, @loewis, @warsaw, @vstinner, @bitdancer, @serhiy-storchaka, @nnja

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/nnja'
closed_at = None
created_at = <Date 2015-12-05.21:19:05.273>
labels = ['3.8', 'type-bug', 'library']
title = "locale.nl_langinfo() can't decode value"
updated_at = <Date 2019-01-09.11:53:37.581>
user = 'https://github.com/serhiy-storchaka'

bugs.python.org fields:

activity = <Date 2019-01-09.11:53:37.581>
actor = 'vstinner'
assignee = 'nnja'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2015-12-05.21:19:05.273>
creator = 'serhiy.storchaka'
dependencies = []
files = []
hgrepos = []
issue_num = 25812
keywords = []
message_count = 4.0
messages = ['255979', '267017', '267192', '333308']
nosy_count = 7.0
nosy_names = ['lemburg', 'loewis', 'barry', 'vstinner', 'r.david.murray', 'serhiy.storchaka', 'nnja']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue25812'
versions = ['Python 3.8']

Linked PRs

• gh-69998: Fix decoding error in locale.nl_langinfo() #124963

[serhiy-storchaka]

>>> import locale
>>> locale.setlocale(locale.LC_NUMERIC, 'uk_UA')
'uk_UA'
>>> locale.getlocale(locale.LC_NUMERIC)
('uk_UA', 'KOI8-U')
>>> locale.nl_langinfo(locale.THOUSEP)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
UnicodeDecodeError: 'locale' codec can't decode byte 0x9a in position 0: Invalid or incomplete multibyte or wide character

Looks as locale.nl_langinfo() always uses the UTF-8 encoding (or may be locale.getpreferredencoding()).

[nnja]

Adding the test below to test__locale.py will reproduce the issue under the following conditions:

• The locale uk_UA is installed on your system.

• 'uk_UA': (',', '\xa0') is added to the known_numerics dictionary in this test file

  @unittest.skipUnless(nl_langinfo, "nl_langinfo is not available")
  def test_lc_numeric_not_char_nl_langinfo(self):
  # Test nl_langinfo against known values/
  # It should still work if there's a mismatch between
  # String & Numeric Locales
  tested = False
  for loc in candidate_locales:
  try:
  setlocale(LC_NUMERIC, loc)
  except Error:
  continue
  for li, lc in ((RADIXCHAR, "decimal_point"),
  (THOUSEP, "thousands_sep")):
  if self.numeric_tester('nl_langinfo', nl_langinfo(li), lc, loc):
  tested = True
  if not tested:
  self.skipTest('no suitable locales')

[bitdancer]

Thanks, Nina. We do have support in test.support for running a test with a specific locale (run_with_locale), so this could be turned into a unit test patch if you or someone else is willing to do that.

[vstinner]

Since this bug has been reported, locale.localeconv() has been fixed in bpo-31900 to temporarily set LC_CTYPE to LC_NUMERIC to decode numeric fields of localeconv() from the proper encoding. I guess that a similar fix can be applied to locale.nl_langinfo(): set LC_CTYPE to LC_NUMERIC if the parameter is a numeric field.

I only knew locale.nl_langinfo(locale.CODESET). I didn't know that this function accepted other arguments :-)

I even wrote an article about these locale bugs :-)
#5191

See also bpo-35697: "decimal: formatter error if LC_NUMERIC uses a different encoding than LC_CTYPE".

[serhiy-storchaka]

Thank you for suggestion @vstinner. #124963 applies the same solution to locale.nl_langinfo().

[serhiy-storchaka]

The changes for localeconv() were not backported, so this one won't be either.