Subject: bug#18109: 24.4.50; `compilation-error-regexp-alist-alist': wrong regexp for Maven

From: Filipp Gunbin <[email-masked]>
Date: Thu, 10 Dec 2020 16:12:25 +0300

On 09/12/2020 19:41 +0100, Mattias Engdegård wrote:

> Quite possible, but the very emission of formalised messages to
> stdout/stderr means that this mode of usage is still acknowledged as
> somewhat common and useful.

Yes, sure.

>> - did we have really that much problems caused by bad
>> performance of compilation regexps?  Because if we did, then maybe we
>> should look at other approaches, like trying to detect the compiler
>> used, and narrow the set of regexps based on it.
>
> This is hard to do in any practical way, not the least because a
> single message buffer may consist of the combined output of dozens of
> different tools -- compilers, linters, build tools, spell checkers,
> testing, stack traces, packaging, and so on. Not to mention the
> practical difficulty of going from the string 'make' to 'GCC version
> 11.2'.
>
> That things work reasonably anyway is very much thanks to the
> prevalence of a few fairly common formats, such as GNU (file:line:
> message).

Yes, btw I see that "gnu" regexp sometimes captures messages which I
expect to be captured by "javac" regexp.  This is not that unexpected,
given the occasional similarity between formats...  I'll look into that
later.

>>  It's natural to expect
>> that many different people would edit these regexps when something
>> doesn't work for them, and expecting that you will always come and fix
>> the things up would not be very fair to you :-)
>
> Very considerate, thank you! There seems to be a fairly good flow of
> reports when something doesn't work. (A more modern and inviting
> bug-reporting system would probably help but that is a completely
> different matter.)
>
> I'm pushing the proposed tightening of gradle-kotlin because the
> principle is right, and even if the Java world internally prefer APIs
> for composing tools, a tighter regexp in Emacs helps performance and
> accuracy for other patterns. Loose regexps form a sort of tragedy of
> the commons.
>
> It seems that we also have forgotten to close the bug; doing that
> now. Thank you again for the insightful comments!

Thank you for careful work.

Filipp