bug#49624: closed (compilation message end-column function off-by-one bug)

[GNU bug Tracking System]

Your message dated Fri, 23 Jul 2021 15:24:55 +0200
with message-id <71FBE546-8821-497D-83A9-A6E4CF0BBBA3@acm.org>
and subject line Re: bug#49624: compilation message end-column function 
off-by-one bug
has caused the debbugs.gnu.org bug report #49624,
regarding compilation message end-column function off-by-one bug
to be marked as done.

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49624: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=49624
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--- Begin Message --- Subject: compilation message end-column function off-by-one bug Date: Sun, 18 Jul 2021 21:00:41 +0200

Compilation message patterns (in compilation-regexp-alist and -alist) can 
indicate starting and ending line and column numbers, either by supplying 
regexp match numbers or functions that return the respective line/column 
numbers when called. In other words, the integer N can be understood as a 
shorthand for the function

(lambda () (and (match-beginning N) (string-to-number (match-string N))))

except that isn't true for the ending column where there is a difference of 1; 
an END-COL function returning 13 means that the error's last column is 12.

There does not seem to be a good justification for this nor is it documented so 
it's probably just a bug; proposed patch attached below. Does it warrant a 
mention in etc/NEWS?

0001-Fix-off-by-one-error-in-compilation-rule-end-column-.patch
Description: Binary data

--- End Message ---

> --- Begin Message ---
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> Subject: 
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> Re: bug#49624: compilation message end-column function off-by-one bug
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> Date: 
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> Fri, 23 Jul 2021 15:24:55 +0200
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> 19 juli 2021 kl. 23.43 skrev Juri Linkov <juri@linkov.net>:
>
> >> Not even 9dc3a46a444a46e00ed3287a3174d73ed9511dac where the funcall for col 
> >> and end-col originated?
> >> In any case, no worry -- I'll deal with it.
> > 
> > My apologies.  This commit is so old that I even don't recognize it.
> > I need to study this code again since I don't remember this part
> > of compile.el.
>
> Thank you, but it's not that important. Let's not overthink it -- I'm treating 
> it as the bug it is and have pushed the obvious fix to master.
>
>
>
> --- End Message ---