Date: Wed, 27 May 2020 21:11:02 +1200 From: Fehmi Noyan ISI <fnoyanisi@yahoo.com> To: Baptiste Daroussin <bapt@FreeBSD.org> Cc: Yuri Pankov <ypankov@fastmail.com>, freebsd-hackers@freebsd.org Subject: Re: diff(1) -N behaviour - Bug 233402 Message-ID: <AFA8A27C-D6DC-4B45-9FDC-9D396EE7A268@yahoo.com> In-Reply-To: <20200527090652.dubjpd2y2n5yfbta@ivaldir.net> References: <B380BAF4-2343-4A22-A26D-13437ECC00C2.ref@yahoo.com> <B380BAF4-2343-4A22-A26D-13437ECC00C2@yahoo.com> <94a82a22-b5c9-b797-30cc-0242f6da1c8a@fastmail.com> <4ADEBC26-0F93-45C1-B775-E6E33E95FDC1@yahoo.com> <efe1c596-f99e-5e1e-3c1a-0e4af38e3464@fastmail.com> <0E0FB885-5D64-41F1-9A8B-8CEDB5884762@yahoo.com> <20200527090652.dubjpd2y2n5yfbta@ivaldir.net>
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> On 27/05/2020, at 9:06 PM, Baptiste Daroussin <bapt@FreeBSD.org> wrote: > > On Wed, May 27, 2020 at 08:52:38PM +1200, Fehmi Noyan ISI via freebsd-hackers wrote: >> >> >>> On 23/05/2020, at 11:47 PM, Yuri Pankov <ypankov@fastmail.com> wrote: >>> >>> Fehmi Noyan ISI via freebsd-hackers wrote: >>>>> On 23/05/2020, at 11:21 PM, Yuri Pankov <ypankov@fastmail.com> wrote: >>>>> >>>>> Fehmi Noyan ISI via freebsd-hackers wrote: >>>>>> Hiya >>>>>> Apparently, after we switched from GNU diff to BSD diff, the -N flag no longer assumes absent files as empty. >>>>>> 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 intentional rather than a missing functionality. >>>>>> 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. >>>>>> What’s your take on this? >>>>>> -N --new-file >>>>>> If a file is found in only one directory, act as if it was found >>>>>> in the other directory too but was of zero size. >>>>>> man for GNU diff >>>>>> -N, --new-file >>>>>> treat absent files as empty >>>>> >>>>> I think both descriptions say the same, i.e. "zero size" == "empty”? >>>> Maybe it’s my interpretation, but if you do not supply the second argument to diff(1), it complains >>>> $ echo “test” > a.txt >>>> $ diff -N a.txt nofile >>>> diff: nofile: No such file or directory >>>> $ >>>> GNU diff assumes an empty file for the missing second file and makes the comparison >>>> $ echo “test” > a.txt >>>> $ diff -N a.txt nofile >>>> 1d0 >>>> < test >>>> $ >>> >>> I must admit that I never used -N without -r, so it's probably the only case that needs fixing? >>> >>> $ mkdir a b >>> $ echo bar > a/foo >>> $ diff -ruN a b >>> diff -ruN a/foo b/foo >>> --- a/foo 2020-05-23 14:44:34.525932000 +0300 >>> +++ b/foo 1970-01-01 03:00:00.000000000 +0300 >>> @@ -1 +0,0 @@ >>> -bar >>> >> >> Took me a while to reply… >> With -N, GNU diff does not give an ENOENT >> >> % echo foo > bar >> % diff bar nofile.txt >> diff: nofile.txt no such file or directory >> % diff -N bar nofile.txt >> 1d0 >> < foo >> >> Do we want BSD diff do the same, i.e. match the -N functionality of GNU diff? >> > Yes we do, if you do provide a patch I would be more than happy to review and > apply it. > > Best regards, > Bapt Cheers… I will be working on it and update bug 233402
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