Walrus operator support

[asottile]

In GitLab by @pawelrubin19 on Nov 27, 2019, 13:16

flake8 crashes when checking python programs that use walrus operator.

python script:

n = 0
while n := n + 1 < 10:
    print("I love flake8")

flake8 output:

"pyflakes" failed during execution due to "'FlakesChecker' object has no attribute 'NAMEDEXPR'"
Run flake8 with greater verbosity to see more details
simple.py:2:9: E701 multiple statements on one line (colon)
simple.py:2:9: E231 missing whitespace after ':'

flake8 installation

I've installed flake8 within pipenv environment

$ pipen install --dev flake8

output of flake8 --bug-report

{
  "dependencies": [
    {
      "dependency": "entrypoints",
      "version": "0.3"
    }
  ],
  "platform": {
    "python_implementation": "CPython",
    "python_version": "3.8.0",
    "system": "Linux"
  },
  "plugins": [
    {
      "is_local": false,
      "plugin": "mccabe",
      "version": "0.6.1"
    },
    {
      "is_local": false,
      "plugin": "pycodestyle",
      "version": "2.5.0"
    },
    {
      "is_local": false,
      "plugin": "pyflakes",
      "version": "2.1.1"
    }
  ],
  "version": "3.7.9"
}

[asottile]

In GitLab by @asottile on Nov 27, 2019, 13:23

flake8 is just a linter framework and does not implement any checks of its own -- you're looking for the plugins pyflakes (which has already fixed the crash) and/or pycodestyle (which has also fixed the spurious warnings)

there's also several dupes of this issue already in all three of the issue trackers 😆

[asottile]

In GitLab by @asottile on Nov 27, 2019, 13:23

closed

[asottile]

In GitLab by @imrehg on Apr 22, 2020, 02:52

Just FYI, duplicate of #595
Also the relevant tool here is pycodestyle (fix should be on current master that is likely going to be 2.6.0, I believe)