Date: Wed, 27 May 2020 23:26:16 -0700 From: Chris <bsd-lists@BSDforge.com> To: Baptiste Daroussin <bapt@FreeBSD.org> Cc: Yuri Pankov <ypankov@fastmail.com>, <freebsd-hackers@freebsd.org>, Fehmi Noyan ISI <fnoyanisi@yahoo.com> Subject: Re: diff(1) -N behaviour - Bug 233402 Message-ID: <3df104a8139d5252b3426ae1600bfc86@udns.ultimatedns.net> In-Reply-To: <20200527090652.dubjpd2y2n5yfbta@ivaldir.net>
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On Wed, 27 May 2020 11:06:52 +0200 Baptiste Daroussin bapt@FreeBSD=2Eorg said > On Wed, May 27, 2020 at 08:52:38PM +1200, Fehmi Noyan ISI via freebsd-hac= kers > wrote: > >=20 > >=20 > > > On 23/05/2020, at 11:47 PM, Yuri Pankov <ypankov@fastmail=2Ecom> wrote: > > >=20 > > > Fehmi Noyan ISI via freebsd-hackers wrote: > > >>> On 23/05/2020, at 11:21 PM, Yuri Pankov <ypankov@fastmail=2Ecom> wrot= e: > > >>>=20 > > >>> Fehmi Noyan ISI via freebsd-hackers wrote: > > >>>> Hiya > > >>>> Apparently, after we switched from GNU diff to BSD diff, the -N fl= ag no > > longer assumes absent files as empty=2E > > >>>> There is a bug report about GNU diff compatibility but when I look= at > > diff(1) man page, I see that not treating absent files as empty is inte= ntional > > rather than a missing functionality=2E > > >>>> If this is not the case, I can work on patch to match to GNU diff > > behaviour, otherwise, this bug report can be closed I think=2E > > >>>> What=E2=80=99s your take on this? > > >>>> -N --new-file > > >>>> If a file is found in only one directory, act as if it was fou= nd > > >>>> in the other directory too but was of zero size=2E > > >>>> man for GNU diff > > >>>> -N, --new-file > > >>>> treat absent files as empty > > >>>=20 > > >>> I think both descriptions say the same, i=2Ee=2E "zero size" =3D=3D "em= pty=E2=80=9D? > > >> Maybe it=E2=80=99s my interpretation, but if you do not supply the s= econd > > argument to diff(1), it complains > > >> $ echo =E2=80=9Ctest=E2=80=9D > a=2Etxt > > >> $ diff -N a=2Etxt nofile > > >> diff: nofile: No such file or directory > > >> $ > > >> GNU diff assumes an empty file for the missing second file and makes= the > > comparison > > >> $ echo =E2=80=9Ctest=E2=80=9D > a=2Etxt > > >> $ diff -N a=2Etxt nofile > > >> 1d0 > > >> < test > > >> $ > > >=20 > > > I must admit that I never used -N without -r, so it's probably the on= ly > > case that needs fixing? > > >=20 > > > $ mkdir a b > > > $ echo bar > a/foo > > > $ diff -ruN a b > > > diff -ruN a/foo b/foo > > > --- a/foo 2020-05-23 14:44:34=2E525932000 +0300 > > > +++ b/foo 1970-01-01 03:00:00=2E000000000 +0300 > > > @@ -1 +0,0 @@ > > > -bar > > >=20 > >=20 > > Took me a while to reply=E2=80=A6 > > With -N, GNU diff does not give an ENOENT > >=20 > > % echo foo > bar > > % diff bar nofile=2Etxt > > diff: nofile=2Etxt no such file or directory > > % diff -N bar nofile=2Etxt > > 1d0 > > < foo > >=20 > > Do we want BSD diff do the same, i=2Ee=2E match the -N functionality of GNU > > diff? > >=20 > Yes we do, Why? If someone wants a GNU diff=2E Can't they simply install it? If FreeBSD diff is to become like GNU diff, what's the point of having a FreeBSD version=2E Apologies in advance if I'm missing anything here=2E Thanks=2E --Chris > if you do provide a patch I would be more than happy to review > and > apply it=2E >=20 > Best regards, > Bapt
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