Dmitry Potapov <dpotapov@xxxxxxxxx> writes:
> On Thu, Jan 03, 2008 at 01:27:27PM -0800, Junio C Hamano wrote:
>> ... I had an
>> impression that we try to stick to a subset of BRE (namely, no
>> \{m,n\}, [::], [==], nor [..]).
>
> I was not aware about this policy, and I am not aware about
> existing any grep that does not grok the expressions I used
> above. So, I thought they are commonly accepted, but I might
> be wrong.
Well I might be wrong too, as I did not vet all the existing use
of grep in our code. That's why I said I had "an impression".
Now I have ("git grep 'grep ' -- 'git-*.sh'"), and it seems to
be that we do stick to a narrow subset of BRE.
* We do not use \{m,n\};
* We do not use -E;
* We do not use ? nor + (which are \{0,1\} and \{1,\}
respectively in BRE) but that goes without saying as these
are ERE elements not BRE (note that \? and \+ you wrote are
not even part of BRE -- making them accessible from BRE is a
GNU extension).
IOW, our scripts' use of grep is very 80'sh ;-)
I do not mind using things that are available in POSIX BRE, but
let's not rely on GNU extension that may cause issues to other
people.
Other things I noticed while looking at "t/*.sh":
* t/t3600-rm.sh and t/5401-update-hooks.sh have unnecessary
uses of egrep that can instead be grep;
* t/t3800-mktag.sh uses egrep but I think it can be grep; also,
I think the use of temporary file expect.pat is unnecessary.
* t/t5510-fetch.sh does use '^[0-9a-f]\{40\} '.
* t/t7001-mv.sh uses -E only to use '.+' when it can just as
easily say '..*' instead.
* t/t7600-merge.sh has two occurrences of (GNU extended) " \+"
that should be " *" for portability. An alternative is to
use grep -E and say " +" instead, but then the other plus
sign on the same line needs to be quoted.
Other than the one in 5510 I consider them log hanging fruits
for janitors.
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