wolf <wolf@wolfsden.cz> writes:

> Reproduction steps:
> 1. Have org-mode and yaml-mode installed.
> 2. C-x C-f /tmp/x.org RET
> 3. Type in:
>
> #+begin_src yaml
>   a:
>     b:
>       c:
> 	d:
> #+end_src
>
> After each line, press RET to go to the next one.  RET is bound to org-return.
> Notice that when you press RET after `c:', emacs will insert a TAB character,
> instead of expected 8 spaces.

Confirmed.
This is caused by `org-src--contents-for-write-back' not adjusting
blank line indentation in some cases.

The attached diff will fix the issue, but git log reveals that the whole
thing is fragile - we adjusted code in this area multiple times with
a number of tricky special cases:

https://git.savannah.gnu.org/cgit/emacs/org-mode.git/commit/?id=e1c49af76
https://git.savannah.gnu.org/cgit/emacs/org-mode.git/commit/?id=70e65a202
https://git.savannah.gnu.org/cgit/emacs/org-mode.git/commit/?id=ee0fd1ec3
https://git.savannah.gnu.org/cgit/emacs/org-mode.git/commit/?id=70e65a202
https://git.savannah.gnu.org/cgit/emacs/org-mode.git/commit/?id=857ae366b
https://git.savannah.gnu.org/cgit/emacs/org-mode.git/commit/?id=91236a3db

https://orgmode.org/list/0f961d3b-a4ef-fbbf-ab16-7ff1af8b2070@gmail.com
https://orgmode.org/list/5DCBAF63-0E88-44AC-B892-1260F37E7E00@manicmind.earth

CCing Bastien and Sébastien, the authors of the previous commits in this
area.

I feel that the whole approach we use now with preserve-fl, use-tabs?,
and preserve-blank-line is overcomplicated. Maybe someone can explain
why we need all these special cases? The code does not reveal a whole lot.