bug#76167: 31.0.50; view-mode un-expected jump-overs

[Tomas Nordin]

Hello

View-mode has less like features like View-search-regexp-forward (/) and
View-search-last-regexp-forward (n). Using them I do some un-expected
observations. Here is a repro:

$ echo 1 word > words
$ echo 2 >> words
$ for n in $(seq 3 6); do echo $n word >> words; done
$ emacs -Q words
M-x view-mode
/ word
n                               ; until on line 6
p                               ; as far up as possible

The observation is that searching backwards jumps over every second
search hit when matches occur on consecutive lines.

Now do

/ !drow

And play with n and p. The bang tells to match every line that does
not match the regex. Again every second expected match is "jumped"
over. In this case also when searching forward. (Expected is that
every line is a search hit).

Maybe not many people use view-mode and it's less-like search
features, and so this was never complained about.

I find that the attached patch solves the problem. What do you think?

In GNU Emacs 31.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version
 3.24.38, cairo version 1.16.0) of 2025-02-09 built on fliptop2
Repository revision: 7e60ceeccbca1b9f67297ad7e9f11fd498b28d4d
Repository branch: master
Windowing system distributor 'The X.Org Foundation', version 11.0.12101007
System Description: Debian GNU/Linux 12 (bookworm)

0001-Start-search-from-beginning-or-end-of-line.patch
Description: Text Data