From: Stefan Monnier <monnier@iro.umontreal.ca>
Cc: Eli Zaretskii <eliz@gnu.org>, 13949@debbugs.gnu.org
Date: Thu, 14 Mar 2013 09:38:08 -0400
Well, since the `fill-paragraph' command at step #4 leaved the buffer
with the same contents, flagging the buffer as modified was
unnecessary in this case.
AFAIK there are two ways to go about it:
- compare the sha1 of the paragraph before and after filling and reset
buffer-modified-p if it shows the text hasn't changed.
This has the disadvantage of scanning the entire buffer, which might
increase paging and memory pressure in general.
- change fill.el so that filling paragraph doesn't just "unfill whole
paragraph + fill whole paragraph" but instead goes line by line, and
only modifies the text where there's a need to.
But it sounds like Dani wants this behavior not only for
fill-paragraph, but for any command that can potentially modify the
buffer, but actually doesn't. This would require to compute sha1
before and after every command that might change the buffer.