JSONDecodeError on Python 3.10

[robd003]

• I am on the latest Poetry version.

• I have searched the issues of this repo and believe that this is not a duplicate.

• If an exception occurs when executing a command, I executed it again in debug mode (-vvv option).

• OS version and name: macOS 11.4

• Poetry version: 1.1.6

• Link of a Gist with the contents of your pyproject.toml file: https://gist.github.com/robd003/9147c6ec95678bd578b6da828f1b3840

Issue

Poetry crashes whenever it evaluates a package for installation. Running poetry install will return JSONDecodeError 100% of the time.

$ poetry install
Installing dependencies from lock file

Package operations: 16 installs, 0 updates, 0 removals

  • Installing sanic-routing (0.6.2): Failed

  JSONDecodeError

  Expecting value: line 1 column 1 (char 0)

  at /usr/local/Cellar/python@3.10/3.10.0b3/Frameworks/Python.framework/Versions/3.10/lib/python3.10/json/decoder.py:355 in raw_decode
      351│         """
      352│         try:
      353│             obj, end = self.scan_once(s, idx)
      354│         except StopIteration as err:
    → 355│             raise JSONDecodeError("Expecting value", s, err.value) from None
      356│         return obj, end
      357│ 

[robd003]

I've tried removing the entire pypoetry cache directory and still having the same issue

[robd003]

Just tried the 1.2.0a1 release and it's working fine.

[robd003]

The 1.1.7 update pushed out today still has the same problem on Python 3.10

[hoefling]

Reproducible with 3.10 on Linux & Windows as well.

[hoefling]

BTW disabling poetry's experimental new installer may be a workaround for now:

$ poetry config experimental.new-installer false

[seandstewart]

I can confirm that the issue is resolved by @hoefling's suggestion.

BTW disabling poetry's experimental new installer may be a workaround for now:

$ poetry config experimental.new-installer false

[dmerejkowsky]

I can confirm I can reproduce with version 1.1.8 here. Poke @python-poetry/triage

[dmerejkowsky]

And this is fixed in 1.2.0a2. I guess we can close this ?

[remram44]

I am glad I found this issue. I wouldn't have known how to even debug this, since Poetry eats the whole traceback I only shows this JSONDecodeError.

Is there a way to print the traceback?

[BSVogler]

Anyone got this on 3.9.7? I get

 • Installing pycparser (2.20): Failed

  JSONDecodeError

  Expecting value: line 1 column 1 (char 0)

  at /usr/local/Cellar/python@3.9/3.9.7/Frameworks/Python.framework/Versions/3.9/lib/python3.9/json/decoder.py:355 in raw_decode

[ksamuel]

Same here, with a project with both 3.9 and 3.10 env. Removing the 3.10 env solve the problem. However, 3.10 will be released in 2 days, so I don't think we should be surprise there are still things that don't work yet.

[jodal]

Reproduced with Poetry 1.1.10 installed on Python 3.9.5 (Ubuntu 21.04 system Python) using pipx.

poetry install started failing immediately when I switched project from Python 3.9.7 to 3.10.0rc2, which is due for final release tomorrow.

Works:

pyenv local 3.9.7
poetry env use $(pyenv which python)
poetry install

Fails:

pyenv local 3.10.0rc2
poetry env use $(pyenv which python)
poetry install

Poetry eats most of the stack trace. I see the following repeated once for each dependency:

  • Installing urllib3 (1.26.7): Failed

  JSONDecodeError

  Expecting value: line 1 column 1 (char 0)

  at /usr/lib/python3.9/json/decoder.py:355 in raw_decode
      351│         """
      352│         try:
      353│             obj, end = self.scan_once(s, idx)
      354│         except StopIteration as err:
    → 355│             raise JSONDecodeError("Expecting value", s, err.value) from None
      356│         return obj, end
      357│ 

Removing the Poetry cache with rm -r ~/.cache/pypoetry/cache/ or m -r ~/.cache/pypoetry/ does not improve the situation.

Disabling the experimental installer with poetry config experimental.new-installer false does resolve the issue, so that at least serves as an indication of what part of Poetry is failing.

[laoshaw]

same issue with python 3.10-rc2 while 3.10 is supposed to be released today. python 3.9 worked well.

with 3.10-rc2, poetry config experimental.new-installer false can make this error disappear.

[playpauseandstop]

Hi all,

Wanted to update you that given error should gone with latest poetry==1.1.11 release.

With given release you don’t need to disable experimental new installer to install your dependencies with poetry at 3.10.0rc2 or 3.10.0.

[ksamuel]

Confirmed for me, fresh stable 3.10 works with latest poetry.

Be careful when upgrading, there are packages that don't have a wheel yet, and you'll need to compile them while in 3.9, you didn't need to.

For me, you can close the ticket.

[emersonmx]

I use rm -rf ~/.cache/pypoetry/cache/.

[finswimmer]

Hello everyone,

as others already mention this issue is solved by a new version of cachecontrol.

If you install poetry by the install-poetry.py scrip, the new version is installed automatically.

If you use the deprecated get-poetry.py script, it is not possible to update the cachecontrol version. get-poetry.py vendores the dependencies based on poetry's lock file. get-poetry.py installs poetry 1.1 which still supports python2. The current version of cachecontrol doesn't support python2 anymore, thus we cannot update the locked version in the 1.1 branch.

TL;DR;: Install poetry with the install-poetry.py to resolve this issue.

fin swimmer

[jcowles]

fresh install with install-poetry.py, deleting poetry.lock, and latest version of cachecontrol did not fix the issue for me, FYI

[jcowles]

The problem for me is that something was spewing "Cannot find the file specified" when launching python. Poetry initializes by running python and printing "sys.path" and then attempts to decode this using the json parser.

The JSON parser fails (loads) because the json string starts with "Cannot find the file specified", and of course that's not valid json.

Still a total mystery what is spewing that string though

[edmondop]

Installed poetry using pip on Windows on 3.9.6, cannot get poetry install to work :( Tried all suggesitons in this post, with no luck

[clintonroy]

Installed poetry using pip on Windows on 3.9.6, cannot get poetry install to work :( Tried all suggesitons in this post, with no luck

This bug is closed. If you have a new bug, please create a new bug report, with all the details requested (inputs, outputs, errors, exactly what commands you ran).

[sandys]

is this bug fixed ? im running a fresh conda install on Windows WSL Ubuntu with Conda and Python 3.10 just now. I had the exact same issue. Only thing that worked was poetry config experimental.new-installer false

[jamesowers-roo]

If anyone else gets here: my issue was not solved by changing config, nor by a complete reinstall of poetry.

Solution: Simply delete and recreate my currently activated virtual environment.

Explanation: as @jcowles suggests above, my currently activated virtual environment python was semi-borked. It was, unbeknownst to me, dishing out a nice error message (but still actually functioning fine somehow):

% python
Error processing line 1 of /Users/james/miniconda/envs/mamod/lib/python3.7/site-packages/distutils-precedence.pth:

  Traceback (most recent call last):
    File "/Users/james/miniconda/envs/mamod/lib/python3.7/site.py", line 168, in addpackage
      exec(line)
    File "<string>", line 1, in <module>
  ModuleNotFoundError: No module named '_distutils_hack'

Remainder of file ignored
Python 3.7.13 (default, Mar 28 2022, 07:24:34)
[Clang 12.0.0 ] :: Anaconda, Inc. on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>>

This looks to be related to pypa/setuptools#2957. Presumably I had broken my venv via various installations.

So my advice if you get a JSONDecodeError with poetry is to simply execute python, and see if you get a weird error and, if so, just trash and recreate your venv.

@clintonroy - we could raise a feature request for poetry to handle the JSON parsing more gracefully? I believe this is done within this file: https://github.com/python-poetry/poetry/blob/ae03bdcdecbb00f2691dbd0f78c08fc010e87779/src/poetry/utils/env.py

[operte]

I just had the same issue. I tried first deleting the virtual environment (as per @jamesowers-roo), but that didn't fix it.

What worked was the solution from @hoefling:

BTW disabling poetry's experimental new installer may be a workaround for now:

$ poetry config experimental.new-installer false

[neersighted]

The JSONDecodeError discussed here is very specifically related to cache-control. Other JSONDecodeErrors are likely caused by broken systems/virtual environments and are more general (not Windows) versions of #6664.

[github-actions]

This issue has been automatically locked since there has not been any recent activity after it was closed. Please open a new issue for related bugs.