On Sat, Aug 22, 2015 at 3:06 PM, René Scharfe <[email protected]> wrote:
> A ZIP file directory has a 16-bit field for the number of entries it
> contains. There are 64-bit extensions to deal with that. Demonstrate
> that git archive --format=zip currently doesn't use them and instead
> overflows the field.
>
> InfoZIP's unzip doesn't care about this field and extracts all files
> anyway. Software that uses the directory for presenting a filesystem
> like view quickly -- notably Windows -- depends on it, but doesn't
> lend itself to an automatic test case easily. Use InfoZIP's zipinfo,
> which probably isn't available everywhere but at least can provides
> *some* way to check this field.
>
> To speed things up a bit create and commit only a subset of the files
> and build a fake tree out of duplicates and pass that to git archive.
>
> Signed-off-by: Rene Scharfe <[email protected]>
> ---
> diff --git a/t/t5004-archive-corner-cases.sh b/t/t5004-archive-corner-cases.sh
> index 654adda..c6bd729 100755
> --- a/t/t5004-archive-corner-cases.sh
> +++ b/t/t5004-archive-corner-cases.sh
> @@ -115,4 +115,44 @@ test_expect_success 'archive empty subtree by direct
> pathspec' '
> check_dir extract sub
> '
>
> +ZIPINFO=zipinfo
> +
> +test_lazy_prereq ZIPINFO '
> + n=$("$ZIPINFO" "$TEST_DIRECTORY"/t5004/empty.zip | sed -n "2s/.* //p")
> + test "x$n" = "x0"
> +'
Unfortunately, this sed expression isn't portable due to dissimilar
output of various zipinfo implementations. On Linux, the output of
zipinfo is:
$ zipinfo t/t5004/empty.zip
Archive: t/t5004/empty.zip
Zip file size: 62 bytes, number of entries: 0
Empty zipfile.
$
however, on Mac OS X:
$ zipinfo t/t5004/empty.zip
Archive: t/t5004/empty.zip 62 bytes 0 files
Empty zipfile.
$
and on FreeBSD, the zipinfo command seems to have been removed
altogether in favor of "unzip -Z" (emulate zipinfo).
One might hope that "unzip -Z" would be a reasonable replacement for
zipinfo, however, it is apparently only partially implemented on
FreeBSD, and requires that -1 be passed, as well. Even with "unzip -Z
-1", there are issues. The output on Linux and Mac OS X is:
$ unzip -Z -1 t/t5004/empty.zip
Empty zipfile.
$
but FreeBSD differs:
$ unzip -Z -1 t/t5004/empty.zip
$
With a non-empty zip file, the output is identical on all platforms:
$ unzip -Z -1 twofiles.zip
file1
file2
$
So, if you combine that with "wc -l" or test_line_count, you may have
a portable and reliable entry counter.
More below...
> +test_expect_failure ZIPINFO 'zip archive with many entries' '
> + # add a directory with 256 files
> + mkdir 00 &&
> + for a in 0 1 2 3 4 5 6 7 8 9 a b c d e f
> + do
> + for b in 0 1 2 3 4 5 6 7 8 9 a b c d e f
> + do
> + : >00/$a$b
> + done
> + done &&
> + git add 00 &&
> + git commit -m "256 files in 1 directory" &&
> +
> + # duplicate it to get 65536 files in 256 directories
> + subtree=$(git write-tree --prefix=00/) &&
> + for c in 0 1 2 3 4 5 6 7 8 9 a b c d e f
> + do
> + for d in 0 1 2 3 4 5 6 7 8 9 a b c d e f
> + do
> + echo "040000 tree $subtree $c$d"
> + done
> + done >tree &&
> + tree=$(git mktree <tree) &&
> +
> + # zip them
> + git archive -o many.zip $tree &&
> +
> + # check the number of entries in the ZIP file directory
> + expr 65536 + 256 >expect &&
> + "$ZIPINFO" many.zip | head -2 | sed -n "2s/.* //p" >actual &&
With these three patches applied, Mac OS X has trouble with 'many.zip':
$ unzip -Z -1 many.zip
warning [many.zip]: 76 extra bytes at beginning or within zipfile
(attempting to process anyway)
error [many.zip]: reported length of central directory is
-76 bytes too long (Atari STZip zipfile? J.H.Holm ZIPSPLIT 1.1
zipfile?). Compensating...
00/
00/00
...
ff/ff
error: expected central file header signature not found (file
#65793). (please check that you have transferred or created the
zipfile in the appropriate BINARY mode and that you have compiled
UnZip properly)
And FreeBSD doesn't like it either:
$ unzip -Z -1 many.zip
unzip: Invalid central directory signature
$
> + test_cmp expect actual
> +'
> +
> test_done
> --
> 2.5.0
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