Subject: Re: bug#13949: 24.3.50; `fill-paragraph' should not always put the buffer as modified

From: Andreas Röhler <[email-masked]>
Date: Thu, 14 Mar 2013 19:34:40 +0100

Am 14.03.2013 18:53, schrieb Eli Zaretskii:
>> From: Stefan Monnier <[email-masked]>
>> Cc: Eli Zaretskii <[email-masked]>,  [email-masked]
>> 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.
>
>
>
>

If fill-paragraph is at stake only, store paragraph in a string at beginning and
compare the result should be enough to reset the modify flag if justified.

Andreas