On Fri, Jun 24, 2016 at 11:56:19AM -0700, Junio C Hamano wrote:
> Jeff King <peff@xxxxxxxx> 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
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