bug#27639: 25.2; Fix syntax for minor mode enabling in dir locals in manual

[Stefan Kangas]

tags 27639 + wontfix
close 27639
thanks

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Kaushal Modi <kaushal.modi@gmail.com>
>> Date: Tue, 11 Jul 2017 16:57:32 +0000
>> Cc: 27639@debbugs.gnu.org
>> 
>>  indent-tabs-mode is the mode variable, so setting it to t is not a
>>  mistake.
>> 
>> The mistake (as explained in the Reddit post) was setting a 'custom-mode' to 
>> t and expecting that that would
>> rightaway enable that 'custom-mode' minor mode.
>
> There's no variable by that name, so it's little surprise that it
> didn't work.
>
>>  But why do you think we should only advertise one method, but not the
>>  other? 
>> 
>> From (emacs) Minor Modes
>> 
>> =====
>> Most minor modes also have a "mode variable", with the same name as
>> the mode command. Its value is non-‘nil’ if the mode is enabled, and
>> ‘nil’ if it is disabled. In general, you should not try to enable or
>> disable the mode by changing the value of the mode variable directly in
>> Lisp; you should run the mode command instead. 
>
> That's unrelated to file-local variables, IMO.
>
>> In any case, as a user, I find it clearer to understand that you must never 
>> enable minor modes by just setting
>> their var; you should call that minor mode fn instead.
>
> And I object to the "never" part.  This is Emacs: we should teach
> users to know and understand what they are doing, not follow recipes
> prepared by others like a kind of cookbook.  If the mode variable is a
> simple variable, and setting it is all that it takes to turn on or off
> the mode, why should we tell users it's wrong?
>
>> Also, if a user uses the (mode . minor) convention instead of (minor-mode . 
>> t), they do not have to worry
>> about declaring them safe.
>
> Let them find that out by themselves, and see if they care.  Who
> knows, we might even find a few bugs that way -- perhaps some mode
> variable should have a safe-local-variable property that we failed to
> specify.
>
> IOW, I think it's wrong to try to save users from themselves.  We
> should provide clear documentation which explains the pros and cons,
> and then let the users decide based on knowledge, not on blindly
> following advice that makes some of the methods "magic".
>
> OK, that's my opinion.  What do others think?

I agree with you Eli, and since no one else has commented in the last
2 years, I'm closing this bug report as wontfix.

Best regards,
Stefan Kangas