use flymake-eslint-executable to access eslint indirectly (#26)

[aecepoglu]

This is a NON-backward-compatible work that replaces flymake-eslint-executable-name and flymake-eslint-executable-args with a single list-type argument: flymake-eslint-executable .

This way we are able to:

1. call eslint through npx (Allow running ESLint using npx #26)
2. call eslint in node_modules/.bin (Prefer locally installed eslint when looking for the executable #29)
3. have one fewer variable to worry about

I've also replaced the existence check with a --version call. I have not really considered its implications though.

Also listed some example values for flymake-eslint-executable in its docs.

Please edit the work as you please so we can get this merged and the issue sorted. Allowing flymake-eslint-executable-name to be a list could be a backward-compatible version of this PR.

[DamienCassou]

There are some conflicts on this PR.

[aecepoglu]

Sorted.

[aecepoglu]

typo

[aecepoglu]

"also" redundant.

[aguynamedben]

Update:

I think my pain was due to Eglot + flymake-eslint. This is working now, inspired by schmir/.emacs.d@f72fcee. Eglot is overly-aggressive and takes over flymake backends, so we have to tell it to not completely take over flymake, then turn on Elgot's flymake backend and flymake-eslint, see joaotavora/eglot#268

;; The Emacs Client for LSP servers
(use-package eglot
  ;; https://github.com/schmir/.emacs.d/commit/f72fcee017aaba3319d1d6e43289210457a91234
  :config
  (defun my/setup-eglot-flymake-backend ()
    "Enable eglot's flymake backend manually."
    (add-hook 'flymake-diagnostic-functions #'eglot-flymake-backend nil t))

  (with-eval-after-load 'eglot
    (setopt eglot-autoshutdown t)
    ;; let me manage flymake on my own
    (add-to-list 'eglot-stay-out-of 'flymake)))

;; Flymake is an Emacs minor mode for on-the-fly syntax checking.
(use-package flymake
  :bind
  (("M-n" . flymake-goto-next-error)
   ("M-p" . flymake-goto-prev-error)))

(use-package flymake-eslint
  :straight (flymake-eslint :type git :host github :repo "aecepoglu/flymake-eslint" :commit "0dec52c2f059b17250e32cb3548c8ed4ac198951")
  :custom
  (flymake-eslint-executable '("npx" "eslint")))

(use-package typescript-ts-mode
  :ensure nil
  :mode
  ("\\.ts\\'" . typescript-ts-mode)
  ("\\.tsx\\'" . tsx-ts-mode)
  :hook
  (typescript-ts-mode . eglot-ensure)
  (typescript-ts-mode . flymake-mode)
  (typescript-ts-mode . my/setup-eglot-flymake-backend)
  (typescript-ts-mode . flymake-eslint-enable)
  (typescript-ts-mode . prettier-js-mode)
  (typescript-ts-mode . copilot-mode))

---

Original Question:
@aecepoglu Thank you for contributing this change, as I've spent hours trying to get flymake-eslint to work as I wish.

Can you give an example of using this with use-package?

I'm trying this:

(use-package flymake-eslint
  :straight (flymake-eslint :type git :host github :repo "aecepoglu/flymake-eslint" :commit "0dec52c2f059b17250e32cb3548c8ed4ac198951")
  :custom
  (flymake-eslint-executable '("npx" "eslint")))

(use-package typescript-ts-mode
  :ensure nil
  :mode
  ("\\.ts\\'" . typescript-ts-mode)
  ("\\.tsx\\'" . tsx-ts-mode)
  :hook
  (typescript-ts-mode . eglot-ensure)
  (typescript-ts-mode . flymake-eslint-enable)
  (typescript-ts-mode . prettier-js-mode)
  (typescript-ts-mode . copilot-mode)
  (tsx-ts-mode . eglot-ensure)
  (tsx-ts-mode . flymake-eslint-enable)
  (tsx-ts-mode . prettier-js-mode)
  (tsx-ts-mode . copilot-mode))

And when I first open a TypeScript file I get

error in process sentinel: Can’t find state for flymake-eslint--checker in ‘flymake--state’ [2 times]

in the echo area and Message buffer, but in the same buffer if I run M-x flymake-eslint-enable again, it starts working.

[aguynamedben]

This branch is working well for me and makes flymake-eslint a lot easier to configure. 👏

[orzechowskid]

completely removing this symbol will cause this package to break for any user who has assigned a value to it.

I suggest continuing to support it for now but apply the define-obsolete-variable-alias macro to tell users they should prefer flymake-eslint-executable instead.

[aecepoglu]

That is true. I welcome you to edit the code as you see fit to respect the older symbols.

[aecepoglu]

@aguynamedben I enable/disable flymake manually so I haven't noticed anything. Your use-package setup seems right though.

I'll keep an eye out for errors I see.