Description

assignee = None
closed_at = None
created_at = <Date 2020-09-24.16:44:20.041>
labels = ['type-bug', '3.8', '3.9', '3.10', 'extension-modules', 'library']
title = 'Inconsistent errors for JSON-encoding NaNs with allow_nan=False'
updated_at = <Date 2020-09-24.17:05:07.621>
user = 'https://github.com/earwig'

activity = <Date 2020-09-24.17:05:07.621>
actor = 'serhiy.storchaka'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Extension Modules', 'Library (Lib)']
creation = <Date 2020-09-24.16:44:20.041>
creator = 'earwig'
dependencies = []
files = []
hgrepos = []
issue_num = 41852
keywords = []
message_count = 1.0
messages = ['377450']
nosy_count = 2.0
nosy_names = ['serhiy.storchaka', 'earwig']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue41852'
versions = ['Python 3.8', 'Python 3.9', 'Python 3.10']

Activity

1. earwig commented on Sep 24, 2020

   

   earwigmannequin

   on Sep 24, 2020

   MannequinAuthor

   More actions

   json.dump vs. json.dumps have inconsistent error messages when encoding NaN with allow_nan=False:

   >>> json.dumps(float('nan'), allow_nan=False)
   ValueError: Out of range float values are not JSON compliant
   >>> json.dump(float('nan'), sys.stdout, allow_nan=False)
   ValueError: Out of range float values are not JSON compliant: nan

   json.dump's error includes the value (which is useful); json.dumps's does not.

   json.dumps uses this C implementation:

   cpython/Modules/_json.c

   Line 1340 in d67de0a

   static PyObject *

   
   json.dump uses this Python implementation:

   cpython/Lib/json/encoder.py

   Line 223 in d67de0a

   def floatstr(o, allow_nan=self.allow_nan,

   (Separately, is it expected that only one uses the C implementation? This seems it could have unexpected performance implications - without testing, I would've expected json.dump to take the "faster" path since it doesn't need to hold the entire encoded string in memory.)
2. earwig

   added

   3.8 (EOL)end of lifeend of life

   3.9 (EOL)end of lifeend of life

   3.10 (EOL)end of lifeend of life

   extension-modulesC modules in the Modules dirC modules in the Modules dir

   stdlibStandard Library Python modules in the Lib/ directoryStandard Library Python modules in the Lib/ directory

   type-bugAn unexpected behavior, bug, or errorAn unexpected behavior, bug, or error

   on Sep 24, 2020
3. ezio-melotti

   transferred this issue fromon Apr 10, 2022
4. serhiy-storchaka

   added this to @serhiy-storchaka's project python-jsonon May 8, 2022
5. serhiy-storchaka

   added this to JSON issueson May 19, 2022
6. WillAyd

   added a commit that references this issue on Nov 6, 2022

   pythongh-86018 Inconsistent errors for JSON-encoding NaNs with allow_…

   17901af
7. nineteendo commented on Jun 30, 2024

   

   nineteendo

   on Jun 30, 2024

   Contributor

   More actions

   This seems to be fixed:

   >>> json.dumps(float('nan'), allow_nan=False)
   Traceback (most recent call last):
     File "<stdin>", line 1, in <module>
     File "C:\Users\wanne\AppData\Local\Programs\Python\Python312\Lib\json\__init__.py", line 238, in dumps
       **kw).encode(obj)
             ^^^^^^^^^^^
     File "C:\Users\wanne\AppData\Local\Programs\Python\Python312\Lib\json\encoder.py", line 200, in encode
       chunks = self.iterencode(o, _one_shot=True)
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
     File "C:\Users\wanne\AppData\Local\Programs\Python\Python312\Lib\json\encoder.py", line 258, in iterencode
       return _iterencode(o, 0)
              ^^^^^^^^^^^^^^^^^
   ValueError: Out of range float values are not JSON compliant: nan
8. picnixz commented on Sep 7, 2024

   

   picnixz

   on Sep 7, 2024

   Member

   More actions

   It was reported in a separate issue #99925 and resolved by #99926. I think this one was just forgotten. I'll close it as completed, even though it's a duplicate (well technically, the other is a duplicate...)

   Reacted by Nice Zombies
9. picnixz

   closed this as completedon Sep 7, 2024
10. github-project-automation

    moved this to Done in JSON issueson Sep 7, 2024
11. github-project-automation

    moved this to Done in @serhiy-storchaka's project python-jsonon Sep 7, 2024

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