bug#36861: 27.0.50; display-fill-column-indicator-mode in log-edit-mode

[Ergus]

Dfci was not designed to be used in this way, and the mode initialization actually sets the character, but in the future it could make many other dynamic tests/checks if needed. So I don't think we should modify it to work the other way you suggest, because for menit is not general enough. But I will follow the Eli's suggestions in this aspects more than my own opinion. 
Any way, if you want to use the mode in this way (for now) you can/need to set the display-fill-column-indicator-character to your desired value and it should work as it is now. But I can't promise that it will work the same way in the future.
But again, probably Eli will suggest a better solution for your use case.

On August 4, 2019 9:39:06 PM GMT+02:00, Juri Linkov <juri@linkov.net> wrote:

 Hi, sorry, I don't understand actually why is so complex this provided code
 in the email. The initialization for display-fill-column-indicator makes
 some checks to set the default character as described in the documentation,
 so no extra code is needed for that in the user side.
 In the initialization I see in this mail, they just set the column's value
 to 78 which can be done also using the variable fill-column for the whole
 major mode too. And actually dfci will recognize it by default and other
 functionalities too so in the general scenario is better to use that one.

 (setq fill-column 78)
 (display-fill-column-indicator t)

 Should work no matters the order. Maybe as you were setting the mode's
 variable instead of calling the function with the same name; the mode
 was not properly initialized.

The problem is that is when the need is to enable dfci, it is simpler
to avoid eval to enable this mode because dfci works fine without using
dfci-mode, i.e. when only variables are set in Local Variables:

  ;;; Local Variables:
  ;;; display-fill-column-indicator: t
  ;;; display-fill-column-indicator-column: 78
  ;;; End:

or in .dir-locals.el:

  (display-fill-column-indicator . t)
  (display-fill-column-indicator-column . 78)

But the display-fill-column-indicator-character can't be set
in Local Variables because its value depends on the current display:
either U+2502 or ?| if the font does not support Unicode characters.

Do you think it would be possible to set the default value of
display-fill-column-indicator-character without calling
display-fill-column-indicator-mode?

-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.