bug#20323: 25.0.50; Emacs's .dir-locals.el should set indent-tabs-mode to nil for emacs-lisp-mode and c-mode

[Dmitry Gutov <dgutov@yandex.ru>]

On 04/16/2015 11:15 PM, Glenn Morris wrote:
>
> I've long since done what seems to me to be the sensible thing:
>
>    use a mode-hook to set indent-tabs-mode to whatever the (pre-existing)
>    file I'm editing seems to use.
>
> I won't claim it's always right (for those files where the indentation
> is mixed), but it's worked pretty well for me.

That sounds like a great approach, but not for this case.

> The fact that indent-tabs-mode has been added to dir-locals now breaks
> this, since dir-locals take precedence over mode hooks (bug#1986).

Why is that a problem? If dir-locals take precedence, then the result 
will be that your commits won't use tabs, except in certain subprojects 
like gnus or erc, which have set file-local vars differently.

That's the original intent behind this proposal: to converge all .el 
files to one indentation style, eventually.

> So for me, this change increases the likelihood of me committing stuff
> that does not match the existing indentation style. Ie, adding it to
> dir-locals without untabifying every file (something which has already
> been rejected) has made things worse IMO.

You seen to consider the presence of different indentation styles in any 
specific file to be the main problem. I disagree: most files already 
contain both styles, and having different styles within the project is 
not much better.