Support org lint

[RlckAstley]

Adding a pull request to support org-lint. The code was originally written several years ago by @czikus and proposed by @zoechi, see #1757

CI/CD and make specs fails with (seq-difference flycheck-checkers checkers) to be 'equal' to 'nil', but instead it was '(org-lint)' which does not match because: (different-types (org-lint) nil). See: https://github.com/RlckAstley/flycheck/actions/runs/6067151846

I'm having a hard time understanding why this is happening. From what I can tell, my style and definition matches spec. I've spent a few hours trying to figure this out, but need to move on. Will try to get on gitter, but seems a bit dead. Also, I'm on liberachat #emacs under RickAstley. Apologies for a premature pull, but I need some help and am a noob.

Also, make check has some odd errors on emacs 25.3 and I'm getting whitespace errors for python related checkers on 28.3 -- not stuff I've touched.

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[cpitclaudel]

I'm having a hard time understanding why this is happening. From what I can tell, my style and definition matches spec. I've spent a few hours trying to figure this out, but need to move on

Sorry for the delay. All checkers that are defined should also appear in the list flycheck-checkers. I think this is what this test is complaining about.

[RlckAstley]

I'm having a hard time understanding why this is happening. From what I can tell, my style and definition matches spec. I've spent a few hours trying to figure this out, but need to move on

Sorry for the delay. All checkers that are defined should also appear in the list flycheck-checkers. I think this is what this test is complaining about.

Hey cpitclaudel, no prob. Sorry for the noobish pull, I'll check on this and see.

[bbatsov]

@RlckAstley Any updates here?

[suhail-singh]

@bbatsov I have been using a modified variant of the code for a while (see
below). Please note the addition of org-export-global-macros to
flycheck-org-lint-variables and the addition of the advice to limit the false
positives. I wouldn't be surprised if flycheck-org-lint-variables needs to be
modified further by users (depending on the specific org-lint checks that are
triggered) and perhaps it should be defined with a flycheck-def-option-var
instead. Note, too, the default value of flycheck-org-lint-load-path that is
specified below and its effect on the arguments passed to Emacs.

(require 'flycheck)

(add-to-list 'flycheck-checkers 'org-lint)

(defconst flycheck-org-lint-form
  (flycheck-prepare-emacs-lisp-form
    (require 'org)
    (require 'org-attach)
    (advice-add 'org-macro-initialize-templates :around
                (lambda (fun &optional default)
                  "Ensure `org-lint' knows about global macros."
                  (require 'ox)
                  (if (and ;; (not noninteractive)
                       ;; (eql this-command 'org-lint)
                       (not default))
                      (funcall fun org-export-global-macros)
                    (funcall fun default))))
    (let ((source (car command-line-args-left))
          (process-default-directory default-directory))
      (with-temp-buffer
        (insert-file-contents source 'visit)
        (setq buffer-file-name source)
        (setq default-directory process-default-directory)
        (delay-mode-hooks (org-mode))
        (setq delayed-mode-hooks nil)
        (dolist (err (org-lint))
          (let ((inf (cl-second err)))
            (princ (elt inf 0))
            (princ ": ")
            (princ (elt inf 2))
            (terpri)))))))

(defconst flycheck-org-lint-variables
  '(org-directory
    org-export-global-macros
    org-id-locations
    org-id-locations-file
    org-attach-id-dir
    org-attach-use-inheritance
    org-attach-id-to-path-function-list)
  "Variables inherited by the `org-lint' subprocess.")

(defun flycheck-org-lint-variables-form ()
  "Make `org-lint' availables available."
  (flycheck-sexp-to-string
   `(progn
      (require 'org-attach)
      ,@(seq-map (lambda (opt) `(setq-default ,opt ',(symbol-value opt)))
                 (seq-filter #'boundp flycheck-org-lint-variables)))))

;;;; options
(flycheck-def-option-var flycheck-org-lint-load-path 'inherit org-lint
  "Load path to use in the Org Lint syntax checker.

When set to `inherit', use the `load-path' of the current Emacs
session during syntax checking.

When set to a list of strings, add each directory in this list to
the `load-path' before invoking the byte compiler.  Relative
paths in this list are expanded against the `default-directory'
of the buffer to check.

When nil, do not explicitly set the `load-path' during syntax
checking.  The syntax check only uses the built-in `load-path' of
Emacs in this case.

Note that changing this variable can lead to wrong results of the
syntax check, e.g. if an unexpected version of a required library
is used."
  :type '(choice (const :tag "Inherit current `load-path'" inherit)
                 (repeat :tag "Load path" directory))
  :risky t
  :package-version '(flycheck . "35.0"))
;;;; org-lint checker
(flycheck-define-checker org-lint
  "Org buffer checker using `org-lint'.

See URL `https://orgmode.org/'."
  :command ("emacs" (eval
                     (let ((args (pcase flycheck-org-lint-load-path
                                   (`inherit `("--batch"
                                               "-u" ,(getenv "USER")))
                                   (p flycheck-emacs-args))))
                       args))
            (eval
             (let ((path (pcase flycheck-org-lint-load-path
                           (`inherit load-path)
                           (p (seq-map #'expand-file-name p)))))
               (flycheck-prepend-with-option "--directory" path)))
            (option "--eval" flycheck-emacs-lisp-package-user-dir nil
                    flycheck-option-emacs-lisp-package-user-dir)
            (option "--eval" flycheck-emacs-lisp-initialize-packages nil
                    flycheck-option-emacs-lisp-package-initialize)
            "--eval" (eval (flycheck-org-lint-variables-form))
            "--eval" (eval flycheck-org-lint-form)
            ;; seems `org-lint' works fine with source (cf. source-inplace)
            "--" source)
  :error-patterns
  ((error line-start line ": " (message) line-end))
  :modes (org-mode)
  :next-checkers (proselint))

;;; End:
(provide 'flycheck-org-lint)
;;; flycheck-org-lint.el ends here