bug#27818: 26.0.50; *occur* buffer misses one match

[Andreas Schwab]

On Jul 25 2017, Dani Moncayo <dmoncayo@gmail.com> wrote:

> Recipe from "emacs -Q":
>
> 1.  Create a new buffer and put there these four lines:
> ---begin-of-buffer---------
> w1    # word 1
> w2    # word 2
> w3    # word 3
> w4    # word 4
> ---end-of-buffer---------
>
> 2. Search for the following regexp:
> "[^[:alnum:]]\(w2\|w3\)[^[:alnum:]]" (without the quotes)
>
> 3.  End the search and type "C-M-s M-p RET M-s o" to launch an *occur* buffer.
>
> The search actually has 2 matches but the *occur* buffer shows only one of 
> them:

The occur engine only considers non-overlapping matches and extends each
match to complete lines.

> ---begin-of-buffer---------
> 1 match for "[^[:alnum:]]\(w2\|w3\)[^[:alnum:]]" in buffer: foo
>       1:w1    # word 1
>        :w2    # word 2
> ---end-of-buffer---------

Note how the first [^[:alnum:]] matches the newline preceding w2, thus
the match includes also line 1.  The next match would start at the
newline in line 2, but that would overlap with the first match.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
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