LSP and Python: flake8 settings are not honored

[synic]

Description

LSP and Python: flake8 settings are not honored

Reproduction guide 🪲

• Start Emacs

• Create a new directory, something like pythonlsptest

• In the directory, type git init

• Create a .flake8 configuration with the following contents:

  [flake8]
  ignore = D100,D101,D102,D103,D104,D105,D106,D107,W503,E203
  application-import-names = pythonlsptest
  max-line-length = 88
  import-order-style = google

• Create a python file with a function in it:

  def test():
      print('test')

Observed behaviour: 👀 💔

Emacs ignores the flake8 configuration. Errors that are set to be ignored
(for example, D100, D103) are shown in flyckeck.

I have tried telling LSP where the configuration file is using .dir-locals.el:

((python-mode
  (eval . (python-black-on-save-mode))
  (fill-column . 88)
  (auto-fill-mode . -1)
  (flycheck-flake8rc . "/pythonlsptest/.flake8")
  (lsp-pylsp-plugins-flake8-config . "/pythonlsptest/.flake8")
 ))

However, this appears to have no effect.

Expected behaviour: ❤️ 😄

The flake8 configuration should be honored like it is in company-mode

System Info 💻

• OS: gnu/linux
• Emacs: 27.1
• Spacemacs: 0.300.0
• Spacemacs branch: develop (rev. 500335a)
• Graphic display: t
• Distribution: spacemacs
• Editing style: vim
• Completion: helm
• Layers:

(auto-completion colors csv dap django emacs-lisp git go helm html ipython-notebook javascript lua markdown major-modes nginx org osx perl5 python rust spacemacs-layouts spell-checking swift syntax-checking sql yaml vimscript
                 (c-c++ :variables c-c++-enable-clang-support t)
                 (lsp :variables lsp-headerline-breadcrumb-enable nil)
                 (shell :variables shell-default-height 30 shell-default-position 'bottom)
                 (typescript :variables typescript-backend 'lsp typescript-fmt-tool 'prettier typescript-fmt-on-save t)
                 (version-control :variables version-control-diff-tool 'diff-hl))

• System configuration features: XPM JPEG TIFF GIF PNG RSVG CAIRO SOUND GPM DBUS GSETTINGS GLIB NOTIFY INOTIFY ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE HARFBUZZ M17N_FLT LIBOTF ZLIB TOOLKIT_SCROLL_BARS GTK3 X11 XDBE XIM MODULES THREADS LIBSYSTEMD JSON PDUMPER LCMS2 GMP

Backtrace 🐾

<<BACKTRACE IF RELEVANT>>

[lebensterben]

try M-x flycheck-select-checker and choose python-flake8

[synic]

@lebensterben This does work, thanks! How do I get it to automatically select python-flake8?

I've got this setup in my .dir-locals.el:

((python-mode
  (eval . (python-black-on-save-mode))
  (fill-column . 88)
  (auto-fill-mode . -1)
  (flycheck--automatically-disabled-checkers . '(python-pylint lsp python-pycompile))
  (flycheck--automatically-enabled-checkers . '(python-flake8))
  (flycheck-add-next-checker 'python-flake8 'lsp)
))

but it sure doesn't want to disable lsp as a checker

[lebensterben]

set flycheck-checker

[synic]

It doesn't work, for some reason lsp gets enabled by default, even with the following:

((python-mode
  (eval . (python-black-on-save-mode))
  (fill-column . 88)
  (auto-fill-mode . -1)
  (flycheck-flake8rc . "/home/synic/Projects/defiq-coinprice-lambda/.flake8")
  (lsp-pylsp-plugins-flake8-config . "/home/synic/Projects/defiq-coinprice-lambda/.flake8")
  (flycheck-checker . 'python-flake8)
))

I've got this in my spacemacs config as well:

  (add-hook 'python-mode-hook
            (lambda ()
              ;; Enable fill column indicator
              ;; (display-fill-column-indicator-mode)
              (display-fill-column-indicator-mode)
              ;; Turn on line numbering
              ;; (linum-mode t)
              (setq fill-column 79)
              ;; set in-block indentation scale
              (setq python-indent-def-block-scale 1)
              ;; Set tab-width to 4
              (setq tab-width 4
                    evil-shift-width 4)
              (setq flycheck-checker 'python-flake8)
              ;; Enable automatic line wrapping at fill column
              (auto-fill-mode t)))

When I check the flycheck setup, is shows lsp as "explicitly selected"

[lebensterben]

lsp blackend is enabled whenever lsp layer is enabled. you have to explicitly set python layer variable to disable it.

this is not a bug and I'm transferring it to discussion.

[synic]

How do you do that? I don't mind LSP and it works fine after setting the checker to python-flake8, but there doesn't seem to be a way to set it up in configuration. I have to open the file and then run (setq flycheck-checker 'python-flake8)

[swinkels]

Hope I understood your question correctly: if you set variable lsp-diagnostics-provider to :none, lsp-mode will not replace the standard flycheck checkers.

I used the Customize interface to set that value: I selected 4 = Use neither flymake nor lsp, saved the settings for future sessions and restarted Emacs. After the restart, the flycheck buffer was populated using the standard Python flycheck checkers, e.g.

 File    Line Col Level    ID     Message (Checker)
 fabfil... 70  27 error           "DeployEvent" has no attribute "path_to_workspace" (python-mypy)
 fabfil... 71  35 error           "DeployEvent" has no attribute "path_to_virtualenv" (python-mypy)

Note the (python-mypy) instead of (lsp) as providing the input.

At the moment I prefer to use the standard Python flycheck checkers as issues with them are much to debug than issues in an lsp server. But maybe I just need to get a bit of confidence in the lsp server - by the way, I use pylsp.

Here's the output to my flycheck-verify-setup:

Syntax checkers for buffer fabfile.py in python-mode:

First checker to run:

  python-flake8
    - may enable:         yes
    - executable:         Found at /home/zzfrd/repos/git/my-app/.tox/py38-dev/bin/python3
    - configuration file: Not found
    - `flake8' module:    Found at "/home/zzfrd/repos/git/my-app/.tox/py38-dev/lib64/python3.8/site-packages/flake8/__init__.py"
    - next checkers:      python-pylint, python-mypy

Checkers that may run as part of the first checker's chain:

  python-mypy
    - may enable:         yes
    - may run:            t
    - executable:         Found at /home/zzfrd/repos/git/my-app/.tox/py38-dev/bin/mypy
    - configuration file: Found at "/home/zzfrd/repos/git/my-app/mypy.ini"

Checkers that could run if selected:

# etc...

[lebensterben]

For choosing lsp vs. non-lsp backend, read python layer documentation.

Also see @swinkels 's comment for a more detailed workaround.