From: Junio C Hamano <gitster@pobox.com>
Date: Fri, 22 Mar 2013 22:32:21 GMT
Subject: Re: [PATCH] Avoid false positives in label detection in cpp diff hunk header regex.
Message-ID: <7vhak35ami.fsf@alter.siamese.dyndns.org>
In-Reply-To: <514CD34F.70107@kdbg.org>

Johannes Sixt <j6t@kdbg.org> writes:

> Am 22.03.2013 16:02, schrieb Junio C Hamano:
>> Vadim Zeitlin <vz-git@zeitlins.org> writes:
>> 
>>> A C++ method start such as
>>>
>>>         void
>>>         foo::bar()
>>>
>>> wasn't recognized by cpp diff driver as it mistakenly included "foo::bar" as a
>>> label. However the colon in a label can't be followed by another colon, so
>>> recognize this case specially to correctly detect C++ methods using this style.
>
> Much appreciated!
>
>>>  PATTERNS("cpp",
>>>          /* Jump targets or access declarations */
>>> -        "!^[ \t]*[A-Za-z_][A-Za-z_0-9]*:.*$\n"
>>> +        "!^[ \t]*[A-Za-z_][A-Za-z_0-9]*:([^:].*$|$)\n"
>> 
>> Hmm.  Wouldn't "find a word (possibly after indentation), colon and
>> then either a non-colon or end of line" be sufficient and simpler?
>> iow, something like...
>> 
>>        "!^[ \t]*[A-Za-z_][A-Za-z_0-9]*:([^:]|$)"
>
> Yes, indeed. We don't need to match more than necessary in a negative
> pattern. The \n must still remain, though.

... because \n is not for matching against the text, but merely to
separate the regular expressions, right?

I also wonder if 

	label :

should also be caught, or is it too weird format to be worth
supporting?