From: Jeff King <peff@peff.net>
To: Junio C Hamano <gitster@pobox.com>
Cc: git@vger.kernel.org, "René Scharfe" <l.s.r@web.de>,
"Robin H. Johnson" <robbat2@gentoo.org>
Subject: Re: [PATCH v3 1/4] t5000: test tar files that overflow ustar headers
Date: Fri, 24 Jun 2016 15:07:44 -0400 [thread overview]
Message-ID: <20160624190744.GA32118@sigill.intra.peff.net> (raw)
In-Reply-To: <xmqq1t3mh0vg.fsf@gitster.mtv.corp.google.com>
On Fri, Jun 24, 2016 at 11:56:19AM -0700, Junio C Hamano wrote:
> Jeff King <peff@peff.net> writes:
>
> > The ustar format only has room for 11 (or 12, depending on
> > some implementations) octal digits for the size and mtime of
> > each file. After this, we have to add pax extended headers
> > to specify the real data, and git does not yet know how to
> > do so.
>
> I am not a native speaker but "After" above made me hiccup. I think
> I am correct to understand that it means "after passing this limit",
> aka "to represent files bigger or newer than these", but still it
> felt somewhat strange.
Yeah, I agree that it reads badly. I'm not sure what I was thinking.
I'll tweak it in the re-roll.
> > +# See if our system tar can handle a tar file with huge sizes and dates far in
> > +# the future, and that we can actually parse its output.
> > +#
> > +# The reference file was generated by GNU tar, and the magic time and size are
> > +# both octal 01000000000001, which overflows normal ustar fields.
> > +#
> > +# When parsing, we'll pull out only the year from the date; that
> > +# avoids any question of timezones impacting the result.
>
> ... as long as the month-day part is not close to the year boundary.
> So this explanation is insuffucient to convince the reader that
> "that avoids any question" is correct, without saying that it is in
> August of year 4147.
I thought that part didn't need to be said, but I can say it
(technically we can include the month, too, but I don't think that level
of accuracy is really important for these tests).
> > +tar_info () {
> > + "$TAR" tvf "$1" | awk '{print $3 " " $4}' | cut -d- -f1
> > +}
>
> A blank after the shell function to make it easier to see the
> boundary.
I was intentionally trying to couple it with prereq below, as the
comment describes both of them.
> Seeing an awk piped into cut always makes me want to suggest a
> single sed/awk/perl invocation.
I want the auto-splitting of awk, but then to auto-split the result
using a different delimiter. Is there a not-painful way to do that in
awk?
I could certainly come up with a regex to do it in sed, but I wanted to
keep the parsing as liberal and generic as possible.
Certainly I could do it in perl, but I had the general impression that
we prefer to keep the dependency on perl to a minimum. Maybe it doesn't
matter.
> > +# We expect git to die with SIGPIPE here (otherwise we
> > +# would generate the whole 64GB).
> > +test_expect_failure BUNZIP 'generate tar with huge size' '
> > + {
> > + git archive HEAD
> > + echo $? >exit-code
> > + } | head -c 4096 >huge.tar &&
> > + echo 141 >expect &&
> > + test_cmp expect exit-code
> > +'
>
> "head -c" is GNU-ism, isn't it?
You're right; for some reason I thought it was in POSIX.
We do have a couple instances of it, but they are all in the valgrind
setup code (which I guess most people don't ever run).
> "dd bs=1 count=4096" is hopefully more portable.
Hmm. I always wonder whether dd is actually very portable, but we do use
it already, at least.
Perhaps the perl monstrosity in t9300 could be replaced with that, too.
> ksh signal death you already know about. I wonder if we want to
> expose something like list_contains as a friend of test_cmp.
>
> list_contains 141,269 $(cat exit-code)
I think we would want something more like:
test_signal_match 13 $(cat exit-code)
Each call site should not have to know about every signal convention
(and in your example, the magic "3" of Windows is left out).
-Peff
next prev parent reply other threads:[~2016-06-24 19:07 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-16 4:35 [PATCH 0/2] friendlier handling of overflows in archive-tar Jeff King
2016-06-16 4:37 ` [PATCH 1/2] archive-tar: write extended headers for file sizes >= 8GB Jeff King
2016-06-20 22:54 ` René Scharfe
2016-06-21 15:59 ` Jeff King
2016-06-21 16:02 ` Jeff King
2016-06-21 20:42 ` René Scharfe
2016-06-21 20:57 ` René Scharfe
2016-06-21 21:04 ` Jeff King
2016-06-22 5:46 ` René Scharfe
2016-06-21 21:02 ` Jeff King
2016-06-22 5:46 ` René Scharfe
2016-06-23 19:21 ` Jeff King
2016-06-21 20:54 ` René Scharfe
2016-06-21 19:44 ` Robin H. Johnson
2016-06-21 20:57 ` Jeff King
2016-06-16 4:37 ` [PATCH 2/2] archive-tar: write extended headers for far-future mtime Jeff King
2016-06-20 22:54 ` René Scharfe
2016-06-22 5:46 ` René Scharfe
2016-06-23 19:22 ` Jeff King
2016-06-23 21:38 ` René Scharfe
2016-06-23 21:39 ` Jeff King
2016-06-16 17:55 ` [PATCH 0/2] friendlier handling of overflows in archive-tar Junio C Hamano
2016-06-21 16:16 ` Jeff King
2016-06-21 16:16 ` [PATCH v2 1/2] archive-tar: write extended headers for file sizes >= 8GB Jeff King
2016-06-21 16:17 ` [PATCH v2 2/2] archive-tar: write extended headers for far-future mtime Jeff King
2016-06-21 18:43 ` [PATCH 0/2] friendlier handling of overflows in archive-tar Junio C Hamano
2016-06-23 23:15 ` [PATCH v3] " Jeff King
2016-06-23 23:20 ` [PATCH v3 1/4] t5000: test tar files that overflow ustar headers Jeff King
2016-06-23 23:31 ` Jeff King
2016-06-24 16:38 ` Johannes Sixt
2016-06-24 16:46 ` Jeff King
2016-06-24 17:05 ` Johannes Sixt
2016-06-24 19:39 ` [PATCH 0/4] portable signal-checking in tests Jeff King
2016-06-24 19:43 ` [PATCH 1/4] tests: factor portable signal check out of t0005 Jeff King
2016-06-24 20:52 ` Johannes Sixt
2016-06-24 21:05 ` Jeff King
2016-06-24 21:32 ` Johannes Sixt
2016-06-24 19:44 ` [PATCH 2/4] t0005: use test_match_signal as appropriate Jeff King
2016-06-24 19:45 ` [PATCH 3/4] test_must_fail: use test_match_signal Jeff King
2016-06-24 19:45 ` [PATCH 4/4] t/lib-git-daemon: " Jeff King
2016-06-24 19:48 ` [PATCH 0/4] portable signal-checking in tests Jeff King
2016-06-24 18:56 ` [PATCH v3 1/4] t5000: test tar files that overflow ustar headers Junio C Hamano
2016-06-24 19:07 ` Jeff King [this message]
2016-06-24 19:44 ` Junio C Hamano
2016-06-24 20:58 ` Jeff King
2016-06-24 22:41 ` Junio C Hamano
2016-06-24 23:22 ` Jeff King
2016-06-24 20:58 ` Eric Sunshine
2016-06-24 21:09 ` Jeff King
2016-06-23 23:21 ` [PATCH v3 2/4] archive-tar: write extended headers for file sizes >= 8GB Jeff King
2016-06-24 19:01 ` Junio C Hamano
2016-06-24 19:10 ` Jeff King
2016-06-24 19:45 ` Junio C Hamano
2016-06-24 19:46 ` Jeff King
2016-06-23 23:21 ` [PATCH v3 3/4] archive-tar: write extended headers for far-future mtime Jeff King
2016-06-24 19:06 ` Junio C Hamano
2016-06-24 19:16 ` Jeff King
2016-06-23 23:21 ` [PATCH v3 4/4] archive-tar: drop return value Jeff King
2016-06-24 11:49 ` Remi Galan Alfonso
2016-06-24 13:13 ` Jeff King
2016-06-24 19:10 ` Junio C Hamano
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