Compiler options such as -MMD confuse header path reload

[harveyt]

I fixed this by pruning such options as follows:

  (defun company-irony-c-headers--clean-compiler-options (options)
    (cond ((null options)
       nil)
      ((or (string-equal "-MF" (car options))
           (string-equal "-MT" (car options))
           (string-equal "-MQ" (car options)))
       (company-irony-c-headers--clean-compiler-options (cddr options)))
      ((string-prefix-p "-M" (car options))
       (company-irony-c-headers--clean-compiler-options (cdr options)))
      (t
       (cons (car options)
         (company-irony-c-headers--clean-compiler-options (cdr options))))))

  (defun company-irony-c-headers--user-compiler-options ()
    "Get compiler options."
    (company-irony-c-headers--clean-compiler-options irony--compile-options))

[hotpxl]

I don't quite like the idea of add specific filtering options since it will eventually put burden on maintenance. But if this is a prevalent problem with compiler options, I could add a customizable filter function, and it will default to id but you could set it if you want. How does that sound to you?

[harveyt]

It was easy enough to override the function as shown above, so I don't mind personally - reporting it here may just be useful if anyone else sees this problem.

I found bear which uses compilation databases/flags filter out just these flags:

https://github.com/rizsotto/Bear/blob/master/bear/main.py.in

Feel free to do what makes sense to you. I'm just glad you wrote this and saved me time.