Python setup: why no line-too-long warnings with pyright
reddit / emacs

----------------------------------------------------------------------
frymye · 2022-10-24 17:06

Hello. I've recently been trying to set up emacs to play nicely with
python. The number of options is a bit overwhelming, but a lot of
signs are pointing towards using lsp with pyright and lsp-ui. So
that's what I've been doing, along with using pyvenv to choose my
virtual environments. But I've noticed that I don't get any warnings
if my lines are too long. I'm not sure why this is? Does it have to do
with my settings, or is this not something lsp/pyright should catch?

----------------------------------------------------------------------
pathemata · 2022-10-24 19:19

You want a style checker called flake8.
I use it with flymake (together with pyright via eglot).

Maybe you can set it up with flycheck (I think flycheck this is the
default with lsp-mode).

----------------------------------------------------------------------
frymye · 2022-10-24 19:34

This is part of what's confusing me. When I verify my flycheck setup,
it looks like I can use either lsp or flake8 as my checker, but not
both? Aren't these doing different things?

----------------------------------------------------------------------
lianacrossk7n · 2022-10-24 20:05

you can use both via checker chain
(https://www.flycheck.org/en/latest/user/syntax-
checkers.html#configuring-checker-chains) but there's a workaround
needed for lsp

[https://github.com/flycheck/flycheck/issues/1762#issuecomment-
750458442](https://github.com/flycheck/flycheck/issues/1762#issuecomme
nt-750458442)

For posterity:

yyoncho:

>As a side note, I think that we will be fine with a solution using
advices in case you don't agree on the obarray change, here it is a
bit more concise version.

    (defvar-local my/flycheck-local-cache nil)

    (defun my/flycheck-checker-get (fn checker property)
      (or (alist-get property (alist-get checker my/flycheck-local-
cache))
          (funcall fn checker property)))

    (advice-add 'flycheck-checker-get :around 'my/flycheck-checker-
get)

    (add-hook 'lsp-managed-mode-hook
              (lambda ()
                (when (derived-mode-p 'sh-mode)
                  (setq my/flycheck-local-cache '((lsp . ((next-
checkers . (sh-posix-bash)))))))))

----------------------------------------------------------------------
frymye · 2022-10-24 20:23

Do I understand correctly that eglot is an alternative to lsp that
won't require such workarounds?

----------------------------------------------------------------------
lianacrossk7n · 2022-10-24 20:32

eglot is an alternative to lsp but it requires a similar workaround:

https://github.com/joaotavora/eglot/issues/268
> Sometimes, in python-mode, this leads to duplicated diagnostics. So,
by default, Eglot uses only the eglot-flymake-backend and supresses
the others.

I use something like:
```
(setq python-flymake-command '("flake8" "-"))
(add-hook 'eglot-managed-mode-hook
  (lambda ()
    (when (derived-mode-p 'python-mode)
      (add-hook 'flymake-diagnostic-functions 'python-flymake nil
t))))
```

----------------------------------------------------------------------
lianacrossk7n · 2022-10-24 20:44

Also as pathemata mentioned: lsp-mode uses flycheck (3rd party) and
eglot uses flymake (built in)

I haven't tried using both at the same time but letting the lsp client
use it's default and you configure extra checkers with the other one
might a workaround that isn't a workaround.

----------------------------------------------------------------------
frymye · 2022-10-25 09:25

I couldn't actually get this to work with the lsp checker. I see
flake8 as second in the chain but I don't seem to actually be getting
flake8 warnings. But the python-pyright checker seems to be working
with flake8 as second in the chain.

So now I'm confused about the difference between lsp and python-
pyright. Both are using pyright in my case.

----------------------------------------------------------------------
lianacrossk7n · 2022-10-27 18:25

I don't use flycheck and I'm not sure how to troubleshoot it.

A new thread to garner help from flycheck users might be something to
consider.