Why does my Flycheck syntax checker not activate automatically?

Question

I wrote a Flycheck frontend for LDC. It installs into Emacs fine, and I remember to require it, but for some reason, it doesn't automatically enable itself when I open a file in d-mode. What did I miss?

Edit: As per request, here are the relevant parts of my init file:

;;D
(autoload 'd-mode "d-mode" "Major mode for editing D code." t)
(add-to-list 'auto-mode-alist '("\\.d[i]?\\'" . d-mode))

;;Flycheck
(require 'flycheck-ldc)
(add-hook 'after-init-hook #'global-flycheck-mode)
(setq-default flycheck-disabled-checkers '(c/c++-clang))

Edit 2: As per request, here is the result of C-c ! v in a d-mode buffer:

Syntax checkers for buffer logic.d in d-mode:

  d-dmd
    - predicate:  nil
    - executable: Not found

Flycheck Mode is enabled.

The following syntax checkers are not registered:

  - d-ldc

 Try adding these syntax checkers to `flycheck-checkers'.

That's impossible to say with as little information as you have given. Please edit your question and add the relevant parts of your init file. Specifically, show your D-Mode and Flycheck setup. — , Apr 24 '15 at 09:18
I have some foggy memory that flycheck keeps a list of major modes where it should be enabled. Don't remember what the variable name. You would probably find it if you looked into its sources. — wvxvw, Apr 24 '15 at 12:34
Do you actually turn flycheck on in your d-mode buffers? For instance, automatically with (add-hook 'd-mode-hook 'flycheck-mode) — deprecated, Apr 27 '15 at 04:42
I just noticed that you enable global-flycheck-mode, so my suggestion in the previous comment should not be necessary. — deprecated, Apr 27 '15 at 13:36
Please type C-c ! v in a D Mode buffer, and add the contents of the buffer which pops up to your question. Feel free to use a screenshot if that's convenient for you. — , Apr 29 '15 at 19:22

score 3 · Answer 1 · answered May 04 '15 at 06:39

3

Flycheck does not find syntax checkers automagically. It's not enough to just define a syntax checker, you also need to register it, by adding it to flycheck-checkers, as Flycheck told you.

(add-to-list 'flycheck-checkers 'd-ldc)

For more information please consult the Flycheck manual which guides you through the whole process of defining a new syntax checker.

answered May 04 '15 at 06:39

My source clearly indicates that I do exactly this (line 62 to be exact). – Koz Ross May 04 '15 at 08:26
I'm sorry, but the output clearly indicates that you did not successfully register the checker. Flycheck doesn't lie—there must be something wrong in your code. Did you check for possible typos? – May 04 '15 at 10:20

score 1 · Answer 2 · answered Apr 27 '15 at 21:54

For malabar-mode, which is enabled in java and groovy buffers, I also added:

(flycheck-define-generic-checker 'jvm-mode-malabar
  "Integrate flycheck with the malabar JVM service."
  :start #'malabar-flycheck-command
  :modes '(java-mode groovy-mode)
)

(add-to-list 'flycheck-checkers 'jvm-mode-malabar)

Why does my Flycheck syntax checker not activate automatically?

2 Answers2