msgspec.json.decode parsing a float value

[Oakington]

Description

msgspec==0.18.6 python 3.8.10 Very odd behavior. Parsing of a stringified JSON with a float value results in the following

` import json import msgspec x = '{"a": 3322.1755149730398}' msgspec.json.decode(x)

{'a': 9.871031767461413e-178}

json.loads(x)

{'a': 3322.1755149730398} `

[jcrist]

Thanks for opening this. I'm unable to reproduce the issue, I suspect this is platform specific. Here's what I see on an x86 linux machine:

In [1]: import msgspec

In [2]: msg = '{"a": 3322.1755149730398}'

In [3]: msgspec.json.decode(msg)
Out[3]: {'a': 3322.1755149730398}

Can you provide some extra platform information (OS, hardware, etc...)? The following script should output some relevant info:

import platform
import sys

uname = platform.uname()

print(f"python: {platform.python_version()}")
for attr in ["machine", "processor", "system", "release"]:
    print(f"{attr}: {getattr(uname, attr)}")
print(f"libc: {platform.libc_ver()}")
print(f"byteorder: {sys.byteorder}")

[Oakington]

python: 3.8.10 machine: AMD64 processor: Intel64 Family 6 Model 165 Stepping 2, GenuineIntel system: Windows release: 10 libc: ('', '') byteorder: little

[jack-mcivor]

I have a similar-ish computer available and can't recreate the issue. Interested

>>> import json
>>> import msgspec
>>> x = '{"a": 3322.1755149730398}'
>>> msgspec.json.decode(x)
{'a': 3322.1755149730398}

python: 3.8.10
machine: AMD64
processor: Intel64 Family 6 Model 141 Stepping 1, GenuineIntel
system: Windows
release: 10
libc: ('', '')
byteorder: little

[jcrist]

Hmmm, we do test on a platform that should be similar enough to this one to catch errors. A few more questions:

• How did you install msgspec? Did you install it with pip from pypi? Using conda? Something else?
• Do you know if you used a prebuilt wheel for your platform (as available on pypi or through conda), or did you compile it yourself from source?

[Oakington]

Installed via pip. I don't know if it was a prebuilt as I just updated my venv to 3.11, upgraded pip wheel and setuptools, re-installed msgspec and it's now working.....Very strange. Let me see if I can go back and get specific builtins versions....Will update shortly.

[Oakington]

OK, reproduced with the following details. Let me know if there's anything else I can provide to track this down.

python Python 3.8.10 (tags/v3.8.10:3d8993a, May 3 2021, 11:34:34) [MSC v.1928 32 bit (Intel)] on win32 py -m pip --version pip 21.1.1 from C:\Users\<name>\Documents\deployment scripts\venv\lib\site-packages\pip (python 3.8) easy_install --version setuptools 47.1.0 from c:\program files (x86)\python37-32\lib\site-packages (Python 3.7) dist-info/WHEEL:

Wheel-Version: 1.0
Generator: bdist_wheel (0.43.0)
Root-Is-Purelib: false
Tag: cp38-cp38-win32

dist-info/RECORD:

msgspec-0.18.6.dist-info/INSTALLER,sha256=zuuue4knoyJ-UwPPXg8fezS7VCrXJQrAP7zeNuwvFQg,4
msgspec-0.18.6.dist-info/LICENSE,sha256=b96LZyOIXoUIgI9lrDcv65fT7uLqsrkdNNeWt1t6xzQ,1498
msgspec-0.18.6.dist-info/METADATA,sha256=g0eKS6M3Jb387PXe1j1Z60C6LZnUW5d1cCuHc72k9-k,7082
msgspec-0.18.6.dist-info/RECORD,,
msgspec-0.18.6.dist-info/REQUESTED,sha256=47DEQpj8HBSa-_TImW-5JCeuQeRkm5NMpJWZG3hSuFU,0
msgspec-0.18.6.dist-info/WHEEL,sha256=57hb2VMKfzdcZEFKIri3BxIFhvran9ahu4uVnDJqFIU,96
msgspec-0.18.6.dist-info/top_level.txt,sha256=8Ysnxa29QLhdPtjPGjyc1hmx3nOmKeu_OAk2682ZdvU,8
msgspec/__init__.py,sha256=4QmZjYKuUQHkpu3H1x4ts2Sg5qcdtiDeo9Gajv4CwPs,1156
msgspec/__init__.pyi,sha256=aUYA7Kox-fxletfoPoVU_HZod3D5lJxzpjLQtZFV2lM,6081
msgspec/__pycache__/__init__.cpython-38.pyc,,
msgspec/__pycache__/_json_schema.cpython-38.pyc,,
msgspec/__pycache__/_utils.cpython-38.pyc,,
msgspec/__pycache__/_version.cpython-38.pyc,,
msgspec/__pycache__/inspect.cpython-38.pyc,,
msgspec/__pycache__/json.cpython-38.pyc,,
msgspec/__pycache__/msgpack.cpython-38.pyc,,
msgspec/__pycache__/structs.cpython-38.pyc,,
msgspec/__pycache__/toml.cpython-38.pyc,,
msgspec/__pycache__/yaml.cpython-38.pyc,,
msgspec/_core.cp38-win32.pyd,sha256=KPEtoqCgZa_KJEFZTmChEcG3Ln676j394LhdYNTKH84,291328
msgspec/_json_schema.py,sha256=bKTi8sOiBuNyEUGJhrjnX4rUhYdjK09MtcDgU8mEo1E,16658
msgspec/_utils.py,sha256=HCvPg_NzLvFpx5SlwnC9SwoYt2UQhldruxG_Ss7RgQA,9048
msgspec/_version.py,sha256=a2wg-8U8xWqU9IRC7WiyOCpBPUcpPFYKTgfQEYpqbZ0,519
msgspec/inspect.py,sha256=uHY4bwjrfNE4UP6rU1PwaZ3-QeyClw-5hpWyXIuFhq4,28896
msgspec/json.py,sha256=kIzpm2NHszkAfAbNcemxq_hUHKt3qxH29yABKH0MnTs,212
msgspec/json.pyi,sha256=-TbORmV1rciB3vMPed-8OPF7Au1_e2fF1iMEQFiAkzY,2995
msgspec/msgpack.py,sha256=JSRLcEqpyCgwy_wD1loF3qHN_ytnCQLc8RX33uATbCU,154
msgspec/msgpack.pyi,sha256=_NpTS8XnjP4ELvqeY-qYWRrsAJi5cvPad7DYICGM3Dw,2566
msgspec/py.typed,sha256=47DEQpj8HBSa-_TImW-5JCeuQeRkm5NMpJWZG3hSuFU,0
msgspec/structs.py,sha256=owU3O3w8yi4_lQYAHIRwM0Hre0Oo_puNbz4SM0GP0ew,2942
msgspec/structs.pyi,sha256=6ob7yIjD6QwMUn_vJHC0CgWgt3CtgRAU2AOUq_1EPGU,902
msgspec/toml.py,sha256=f0Vte-oW3WK5avMFHf22WuqoccaaVGGKFu98m43wu9Q,5389
msgspec/yaml.py,sha256=LT2T0HW-FtHq_wGBD3sGtpgXspN6N5SmesV1BHrSvPs,5260

[jack-mcivor]

Ah that's 32-bit Python on a 64-bit system I think? I won't be able to help more but for completeness, my Python installation was 64 bit.

[jcrist]

Yeah, and we don't ship 32-bit windows wheels, so that definitely was compiled on your machine. Not surprised there's compatibility bugs. Were you intentionally using a 32 bit python version, or is that just incidental? I'd been viewing 32-bit windows builds as a platform with low enough usage that it wasn't worth supporting (conda-forge, for example, doesn't ship any win32 builds). If I'm mistaken here we could (with some effort) probably squash these bugs and start building wheels for that platform as needed.

[Oakington]

No, it's not needed. It was an older install that I used for one off scripts. Anything in PROD is x64. Might be worth a warning somewhere? Not sure what's best. Just threw me off and I wouldn't have caught it if I wasn't looking at that specific value in the payload.

I really appreciate this library. It's so fast that I'm refactoring a lot of my APIs to use it as well as proselytizing to my coworkers that are using other parsing libs. So thank you for all your efforts!

[jcrist]

Thanks for the kind words, and glad you've figured out the issue. I've added a check for this in #696 that should prevent anyone else from trying to build msgspec on 32-bit windows in the future.