Dpkg::Control::HashCore: Do not emit trailing space on field empty first line

This spurious space is unnecessary and takes a non-insignificant amount
of disk space on archive index files for example.

Update dpkg-dev Breaks on devscripts to version << 2.14.4, as previous
versions of debchange expect a trailing space from dpkg-parsechangelog
output.

Closes: #749044

Based-on-patch-by: Johannes Schauer <j.schauer@email.de>

1 files changed, 9 insertions, 6 deletions

diff --git a/scripts/Dpkg/Control/HashCore.pm b/scripts/Dpkg/Control/HashCore.pm
index af41c7e90..05c168978 100644
--- a/scripts/Dpkg/Control/HashCore.pm
+++ b/scripts/Dpkg/Control/HashCore.pm
@@ -349,22 +349,25 @@ sub output {
             # Skip whitespace-only fields
             next if $$self->{drop_empty} and $value !~ m/\S/;
 	    # Escape data to follow control file syntax
-	    my @lines = split(/\n/, $value);
-	    $value = (scalar @lines) ? shift @lines : '';
+	    my ($first_line, @lines) = split /\n/, $value;
+
+	    my $kv = "$key:";
+	    $kv .= ' ' . $first_line if $first_line;
+	    $kv .= "\n";
 	    foreach (@lines) {
 		s/\s+$//;
 		if (/^$/ or /^\.+$/) {
-		    $value .= "\n .$_";
+		    $kv .= " .$_\n";
 		} else {
-		    $value .= "\n $_";
+		    $kv .= " $_\n";
 		}
 	    }
 	    # Print it out
             if ($fh) {
-	        print { $fh } "$key: $value\n"
+	        print { $fh } $kv
 	            or syserr(_g('write error on control data'));
             }
-	    $str .= "$key: $value\n" if defined wantarray;
+	    $str .= $kv if defined wantarray;
 	}
     }
     return $str;