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Re: [PATCH] t4062: stop using repetition in regex




Am 09.08.2017 um 00:26 schrieb Junio C Hamano:
> Junio C Hamano <gitster@xxxxxxxxx> writes:
> 
>> So I find Dscho's concern quite valid, even though I do believe you
>> when you say the code somehow segfaults.  I just can not tell
>> how/why it would segfault, though---it is possible that regexec()
>> implementation is stupid and does not realize that it can return early
>> reporting success without looking at the rest of the buffer, but
>> somehow I find it unlikely.
>>
>> Puzzled.
>>
>>> You get different results?  How is that possible?  The search string is
>>> NUL-terminated in each case, while the point of the test is that the
>>> file contents isn't, right?
> 
> Intellectual curiosity tells me we may want to find out why it
> fails, but in the meantime, I think replacing the test with "0$" to
> force the scanner to find either the end of line or the end of the
> buffer may be a good workaround.  We do not have to care how many of
> random bytes are in front of the last "0" in order to ensure that
> the regexec_buf() does not overstep to 4097th byte, while seeing
> that regexec() that does not know how long the haystack is has to do
> so, no?

Our regexec() calls strlen() (see my other reply).

Using "0$" looks like the best option to me.

René