Re: git-svn failure when symlink added in svn

[Junio C Hamano <junkio@cox.net>]

Eric Wong <normalperson@yhbt.net> writes:

> Junio C Hamano <junkio@cox.net> wrote:
>> diff --git a/git-svn.perl b/git-svn.perl
>> index 4be8576..cef6697 100755
>> --- a/git-svn.perl
>> +++ b/git-svn.perl
>> @@ -2464,15 +2464,15 @@ sub close_file {
>>  	my $hash;
>>  	my $path = $self->git_path($fb->{path});
>>  	if (my $fh = $fb->{fh}) {
>> -		seek($fh, 0, 0) or croak $!;
>> +		sysseek($fh, 0, 0) or croak $!;
>>  		my $md5 = Digest::MD5->new;
>>  		$md5->addfile($fh);
>
> We may want to keep the plain seek() here and do both seek and sysseek,
> I'm not sure if $md5->addfile() uses read or sysread internally.

Ok.  The seek before Digest::MD5 can stay as it has been that
way for a long time without causing problems.  How about this as
an replacement then?

-- >8 --
[PATCH] Fix symlink handling in git-svn, related to PerlIO

After reading the leading contents from a symlink data obtained
from subversion, which we expect to begin with 'link ', the code
forked to hash the remainder (which should match readlink()
result) using git-hash-objects, by redirecting its STDIN from
the filehandle we read that 'link ' from.  This was Ok with Perl
on modern Linux, but on Mac OS, the read in the parent process
slurped more than we asked for in stdio buffer, and the child
did not correctly see the "remainder".

This attempts to fix the issue by using lower level sysseek and
sysread instead of seek and read to bypass the stdio buffer.

Signed-off-by: Junio C Hamano <junkio@cox.net>
---
 git-svn.perl |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/git-svn.perl b/git-svn.perl
index 4be8576..6f509f8 100755
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -2470,9 +2470,9 @@ sub close_file {
 		my $got = $md5->hexdigest;
 		die "Checksum mismatch: $path\n",
 		    "expected: $exp\n    got: $got\n" if ($got ne $exp);
-		seek($fh, 0, 0) or croak $!;
+		sysseek($fh, 0, 0) or croak $!;
 		if ($fb->{mode_b} == 120000) {
-			read($fh, my $buf, 5) == 5 or croak $!;
+			sysread($fh, my $buf, 5) == 5 or croak $!;
 			$buf eq 'link ' or die "$path has mode 120000",
 			                       "but is not a link\n";
 		}
-- 
1.5.2.rc0.781.g5868