F821 undefined name gives wrong line number (alwasy line 1) when variable is in an f-string

[asottile]

In GitLab by @samuelcolvin on Feb 22, 2017, 06:07

setup:

➤  flake8 --bug-report
{
  "dependencies": [
    {
      "dependency": "setuptools",
      "version": "34.2.0"
    }
  ],
  "platform": {
    "python_implementation": "CPython",
    "python_version": "3.6.0+",
    "system": "Linux"
  },
  "plugins": [
    {
      "plugin": "mccabe",
      "version": "0.6.1"
    },
    {
      "plugin": "pycodestyle",
      "version": "2.3.1"
    },
    {
      "plugin": "pyflakes",
      "version": "1.5.0"
    }
  ],
  "version": "3.3.0"
}

foobar.py:

a = 'this is a test'
b = f'this is a good fstring: {a}'
c = f'this is a bad fstring: {abc}'

➤  flake8 foobar.py 
foobar.py:1:2: F821 undefined name 'abc'

You would expect the error to say line 3 not line 1.

[asottile]

In GitLab by @samuelcolvin on Feb 22, 2017, 06:10

sorry, realised this should have been posted to pyflakes.

[asottile]

In GitLab by @samuelcolvin on Feb 22, 2017, 06:10

closed

[asottile]

In GitLab by @samuelcolvin on Feb 22, 2017, 06:18

Error in pyflakes it slightly different, I'm now a bit confused about whether this should be posted here or on the pyflakes' launchpad.

I'll leave it open here, let me know if you want me to close here and resubmit elsewhere.

[asottile]

In GitLab by @samuelcolvin on Feb 22, 2017, 06:18

reopened

[asottile]

In GitLab by @sigmavirus24 on Feb 22, 2017, 06:27

So https://bugs.launchpad.net/pyflakes/+bug/1666811 was reported this morning. PyFlakes doesn't report columns so the error may be slightly dissimilar. That said, this is definitely a bug in pyflakes.

[asottile]

In GitLab by @samuelcolvin on Feb 22, 2017, 06:29

Thanks, sorry for missing that. I'm guessing you want the issue left open until it's fixed upstream?

[asottile]

In GitLab by @blueyed on Feb 15, 2018, 16:18

According to https://bugs.launchpad.net/pyflakes/+bug/1666811/comments/3 this is fixed/improved with Python 3.6.3.

[asottile]

In GitLab by @sigmavirus24 on Oct 20, 2018, 10:17

http://flake8.pycqa.org/en/latest/internal/contributing.html#filing-a-bug

[asottile]

In GitLab by @sigmavirus24 on Oct 20, 2018, 10:17

closed

[asottile]

In GitLab by @asottile on Oct 2, 2020, 16:37

changed the description