JSONDecodeError on Python 3.10

• 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│ 

[hoefling]

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

$ poetry config experimental.new-installer false

[hoefling]

Reproducible with 3.10 on Linux & Windows as well.