Git::cat_blob: allow using an empty blob to fix git-svn breakage

Recent "git-svn optimization" series introduced Git::cat_blob() subroutine
whose interface was broken in that it returned the size of the blob but
signalled an error by returning 0.  You can never use an empty blob with
such an interface.

This fixes the interface to return a negative value to signal an error.

Reported by Björn Steinbrink.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-svn.perl b/git-svn.perl
index 37976f25057ac5d3c91a13ab8564a4cb40f59f79..3a6eb1cb9da752a3a6fa35d781cade9c886e03b9 100755 (executable)
--- a/git-svn.perl
+++ b/git-svn.perl
@@ -3191,7 +3191,7 @@ sub apply_textdelta {
        if ($fb->{blob}) {
                print $base 'link ' if ($fb->{mode_a} == 120000);
                my $size = $::_repository->cat_blob($fb->{blob}, $base);
-               die "Failed to read object $fb->{blob}" unless $size;
+               die "Failed to read object $fb->{blob}" if ($size < 0);
 
                if (defined $exp) {
                        seek $base, 0, 0 or croak $!;
@@ -3570,7 +3570,7 @@ sub chg_file {
                $self->change_file_prop($fbat,'svn:special',undef);
        }
        my $size = $::_repository->cat_blob($m->{sha1_b}, $fh);
-       croak "Failed to read object $m->{sha1_b}" unless $size;
+       croak "Failed to read object $m->{sha1_b}" if ($size < 0);
        $fh->flush == 0 or croak $!;
        seek $fh, 0, 0 or croak $!;
 

diff --git a/perl/Git.pm b/perl/Git.pm
index 6ba8ee5c0d209704fdf1c9d58f63579d3a7e0836..d05b633b64ac6440f8c86405beb13df281bde989 100644 (file)
--- a/perl/Git.pm
+++ b/perl/Git.pm
@@ -811,12 +811,12 @@ sub cat_blob {
        my $description = <$in>;
        if ($description =~ / missing$/) {
                carp "$sha1 doesn't exist in the repository";
-               return 0;
+               return -1;
        }
 
        if ($description !~ /^[0-9a-fA-F]{40} \S+ (\d+)$/) {
                carp "Unexpected result returned from git cat-file";
-               return 0;
+               return -1;
        }
 
        my $size = $1;